843 A.2d 1042 (2004) 179 N.J. 1

Kathleen VERDICCHIO and Vincent Verdicchio, Individually and as Executors of the Estate of Stephen Verdicchio, Plaintiffs-Appellants and Cross-Respondents,
v.
Anthony RICCA, M.D. and Hazlet Health Care, Defendants-Respondents and Cross-Appellants.

Supreme Court of New Jersey.

Argued October 7, 2003. Decided March 15, 2004.

*1045 Philip G. Auerbach, Red Bank, argued the cause for appellants and cross respondents (Auerbach & Ryan, attorneys).

Richard A. Grossman, Brick, argued the cause for respondents and cross appellants (Grossman, Kruttschnitt, Heavey & Jacob, attorneys; Mr. Grossman and Thomas J. Heavey, on the briefs). *1043

*1044 Justice LONG delivered the opinion of the Court.

On appeal in this medical malpractice case, we revisit the thorny problem of assessing proximate cause in the context of harm generated by concurrent forces. More particularly, we are called on to apply the increased risk doctrine in a case alleging failure to diagnose cancer. On the facts before us, it is not known whether the cancer had metastasized at the time of the deviation. As a result, the trial court set aside a substantial verdict in plaintiffs' favor and the Appellate Division affirmed, essentially holding that the absence of proof regarding metastasis was a fatal flaw in plaintiffs' increased risk analysis. We now reverse, on the ground that those courts too narrowly characterized the notion of increased risk and required quantification that is not necessary under our jurisprudence.

I

The matter arose when plaintiffs Kathleen and Vincent Verdicchio, individually *1046 and as executors of the estate of their son, Stephen Verdicchio, filed a wrongful death and survivorship action against defendant, Dr. Anthony Ricca, alleging malpractice in connection with Dr. Ricca's failure to timely diagnose Stephen's cancer. Dr. Ricca answered, denying the allegations of the complaint. The matter was tried over eight days. At the end of the Verdicchios' case and again at the conclusion of the trial, Dr. Ricca moved to dismiss the complaint. The trial court reserved decision on both motions.

The jury returned a verdict declaring that Dr. Ricca had been negligent in his treatment of Stephen; that the negligence "increased the risk" of a bad outcome; and that that increased risk was a "substantial factor" in bringing about the ultimate harm that befell Stephen. It awarded the estate $6,500,000.00 in the survival action and $1,500,000.00 in the wrongful death action. Because the jury concluded that the underlying disease, osteosarcoma, was responsible for 45% of the outcome and Dr. Ricca for 55%, the total judgment of $8,000,000 was molded to $4,400,000.00. Dr. Ricca then moved for a judgment nothwithstanding the verdict.

The trial court granted that motion along with the previous dismissal motions on the ground that:

In my opinion the plaintiffs must prove that a chance of avoiding the harm existed. Plaintiff must have shown this by proving that Stephen's cancer had not metastasized in January of 1994. However, plaintiffs took the stance that Stephens's cancer had not metastasized to his lungs by January of 1994.

But plaintiffs ... did not prove that fact. In fact, plaintiffs' expert was unable to render any opinion regarding the metastasis of Stephen's cancer. Thus, plaintiffs did not meet the burden of proving an element of the modified proximate causation test.

The Appellate Division affirmed the trial court's decision concluding that "plaintiffs failed to establish by expert testimony that Stephen was suffering from non-metastasized cancer at the time of the alleged deviation by defendant, and thus, failed to meet their burden of proof in an `increased risk' case under the modified proximate causation test enunciated in Evers v. Dollinger, 95 N.J. 399, 471 A.2d 405 (1984), Scafidi v. Seiler, [119] N.J. 93, 574 A.2d 398 (1990), and Gardner v. Pawliw, 150 N.J. 359, 696 A.2d 599 (1997)." The panel held that the jury was left with no proof, other than speculation, that Stephen's condition was such that, had the defendant diagnosed it as of January 1994, Stephen's chance of survival would have been increased.

The Verdicchios filed a petition for certification and Dr. Ricca, a cross-petition. We granted both, Verdicchio v. Ricca, 175 N.J. 79, 812 A.2d 1111 (2002), and now reverse.

II

The relevant facts established at trial are as follows: Dr. Ricca, a board certified internist, became Stephen Verdicchio's primary care physician on May 22, 1993, when Stephen was seventeen years old. Dr Ricca was selected by the Verdicchio family from a list of eligible physicians associated with the family's insurance carrier, Oxford Health. On that visit, Dr. Ricca recorded that Stephen was generally healthy but experienced some lethargy and difficulty running track at school. He also reported bowel movements after each meal.

Stephen saw Dr. Ricca again on August 3, 1993, to obtain medical clearance to compete on his high school track team. According to Mrs. Verdicchio, during that visit, she told the doctor that Stephen continued to have bowel problems and some *1047 difficulty breathing. Dr. Ricca ordered blood tests, a chest x-ray, and an electrocardiogram that all proved to be normal.^[1] According to Dr. Ricca, neither Mrs. Verdicchio nor Stephen mentioned any stomach pains, bowel problems or diarrhea. Dr. Ricca also examined Stephen's legs and knees and did not record any evidence of pain or deficits in range of joint motion.

Dr. Ricca again saw Stephen on October 2, 1993, when he administered a flu shot. Mrs. Verdicchio testified she made that appointment because Stephen was not feeling well, was still tired and lifeless, and continued to have bowel problems. He also continued to lose weight. Dr. Ricca denied that those symptoms were even mentioned during the visit. His records merely indicate that Stephen went in for a flu shot. In that connection, Mrs. Verdicchio testified as follows:

A: I went there because he wasn't feeling good. He wasn't getting better. He was tired. He was lifeless. He was losing weight. I kept watching this young man who would eat and I should be buying him larger size shirts or bigger pants or what have you and it wasn't coming to that.... So I took him to the doctor.

Q. Now, did you take him merely to get a flu shot?

A. The flu shot never entered my mind. Why would you give a high school student a flu shot?

Q. Okay. Now, in Dr. Ricca's records he says, "Allergies, many environmental allergies," he says. Did you tell him that he had allergies or did you tell him about these complaints?

A. I told him about the complaints and probably what used the word, his allergies coming off of going into a season again up there. But I know that every time we walked in I felt like a broken record. Every time I walked in, I was saying the same things.

Mrs. Verdicchio testified that in response to her expressed concerns during that visit about Stephen's bowel problems, Dr. Ricca told her she was a paranoid mother not ready to let go of her son, and that that was adding stress for Stephen. She also testified that the doctor told her the bowel movements could be a sign of anorexia, which is found many times in runners, and that Stephen could also be using laxatives or other drugs. Dr. Ricca denied making any of those statements.

Mrs. Verdicchio recounted that in the late fall of 1993 to early January 1994, Stephen continued to complain of pain in his left leg and continued to lose weight. On January 25, 1994, Stephen and Mrs. Verdicchio went to see Dr. Ricca. Mrs. Verdicchio recounted that Stephen complained of problems with bowel movements, diarrhea, weight loss and specifically with pain in his left leg. Dr. Ricca denied that Stephen or his mother raised the issue of leg pain. He recorded in his computerized "Patient Chart Notes" that Stephen "appears seriously ill." The chart also indicated under "Current Complaint"—"diarrhea, constipation, and stomach pains." The patient history further described:

Otherwise healthy 17 year old male presents with several month history of diarrhea. The patient states that he has had periods of normal bowel movements followed by days of watery diarrhea. The patient states that he has never seen blood in the stool. The stool has never been black. He states that after a few mouthfuls of food he has to evacuate his bowels. He has occasional crampy abnormal pain. No fever, sweats, chills. Some arthralgias of the knees but the *1048 patient is a track runner. He is not yet sexually active. No vomiting. The patient states that he has periods of constipation. Actually, the patient has lost 17 pounds over the last 5 months.

[Emphasis added.]

Mrs. Verdicchio testified that Dr. Ricca never suggested even indirectly that Stephen was seriously ill:

A. No, no. He never told me that. If he would have told me that,—don't you think I would have went to another doctor? No mother, no parent has a doctor say to you, your child is seriously ill, when you know in your heart there is already something wrong and ignore it. No mother would do that. I'm sorry.

Mrs. Verdicchio stated in regard to the leg pain that Dr. Ricca told them that track runners generally have aches and pains in the legs, and that if Stephen was going to be a track runner he would have to accept the pain. Dr. Ricca testified that he asked Stephen if he was having any joint pain, and Stephen indicated achiness in both knees. The doctor acknowledged that he did not examine Stephen's legs or knees, attributing the complaint of pain to Stephen's running:

Q. You have been criticized for not examining Stephen's legs that day when you elicited this response to your question about joint pain.

A. Yes.

Q. Why didn't you examine his knees or legs that day?

A. This was a directed examination. We were looking for the cause of his diarrhea. The arthralgias related to the knees were an incidental to what was going on. The question of the arthralgias was dedicated to finding out what the cause of the diarrhea was. I would also say that in examining the patient, you would take an overview of the patient. And even though it's not marked down that the knees were specifically examined, I couldn't attest that they weren't examined.

Dr. Ricca ordered laboratory tests that revealed an elevated white blood count, as well as elevated neutriphils, and uric acid levels. Dr. Ricca also recommended that Stephen see a gastroenterologist and authorized a referral to Dr. Kern who examined Stephen on February 4, 9 and 22, 1994.

Dr. Kern reported to Dr. Ricca on March 7, 1994, that he had not found evidence of suspected inflammatory bowel disease, and that Stephen had "improved significantly on just Imodium [an over-the-counter drug that stops diarrhea by preventing the bowel muscles from contracting] having gained ten pounds in two weeks." Dr. Kern indicated that he discussed with Mrs. Verdicchio that Stephen's symptoms could be related to irritable bowel syndrome secondary to emotional distress relating to his relationship with her. He also recommended that if Stephen's symptoms should recur or not continue to improve, Stephen should receive a D-Xylose test to determine if he had malabsorption syndrome.

On February 12, 1994, Stephen called Dr. Ricca regarding the results of tests administered by Dr. Kern. Dr. Ricca testified that although he was not sure whether his office had received those results yet, he called Stephen back that same day but that no one answered. Thereafter, according to Dr. Ricca, there was no further contact between him and Stephen until May 3, 1994.

Mrs. Verdicchio testified regarding Stephen's condition after the visit with the gastroenterologist:

A. It seemed like for a few weeks he was getting better .... and then all of a sudden, almost like the turning of a television channel, he was starting to lose weight again, he was getting up and *1049 going to the bathroom, complaining. He had always complained of the leg, but he was back complaining of it severely. The knee.

Q. What did you do as a result?

A. I called Dr. Ricca's office.

Q. And did you speak to him personally?

A. Yes.

Q. And tell us—

Court: Can we fix a time frame?

Q: Can we fix a time frame? When was this? Do you have any idea of when it was?

A. I have an idea, because Stephen was still, it was spring track. It was probably the end of April, in the beginning of May, because we were still, he was finishing another track season and I was really concerned.

Q. And what did—tell us about the conversation.

A. The conversation, I can't give it word to word, but the concept was that the track season was ending and to give Stephen a break, but that pressure was going to come on more because he was going to be applying to colleges and all. But to see, again, the same thing he had said the season before, see how it is after he rests it awhile and see how he feels after being out of school and not having the pressures of the school.

Dr. Ricca examined Stephen again on May 3, 1994, after Stephen collapsed during a track meet and was experiencing pain in his left leg. Dr. Ricca's "Patient Chart Notes" indicated that Stephen complained of pain before and after, but not during running, from his left hip down to the anterior shin. Dr. Ricca recorded that no known trauma existed but that there was "tenderness over left thigh at the lateral aspect with muscle edema." He recommended rest for several days and then ice followed by heat after running, along with Tylenol for the pain and an Ace bandage for support. Dr. Ricca did not weigh Stephen on that visit and did not ask about his bowel problems. He also did not order an x-ray. With respect to the x-ray, Stephen called Mrs. Verdicchio from Dr. Ricca's office. She testified:

A. On May 3rd, 1994, Stephen ran a track meet ... He fell on the field ... I never got up there, because Stephen called me from Dr. Ricca's office and said, I remember the first thing he said to me is, I can run. And I thought, oh God. And he said, it's okay. I'm okay. And I said, are you going for an x-ray and he said, no and I asked him to put Dr. Ricca on. And Dr. Ricca said, I keep telling you, it's a sprain, he'll be okay. And I said, and he's got a big meet in two days. If he rests it and he puts ice on it, there is no reason he can't participate.

On May 5, 1994, Stephen returned to Dr. Ricca's office and was seen by an associate, Dr. Stillwell.^[2] Stephen reported that he had applied ice and heat as directed but had continued to run, and had again collapsed during a track meet. Dr. Stillwell recommended that Stephen continue the same treatment ordered by Dr. Ricca. Mrs. Verdicchio testified that she called Dr. Ricca's office on May 9, 1994, because Stephen continued to experience pain, but that the doctor did not return her call. Dr. Ricca testified that a member of his office staff told Mrs. Verdicchio to call back when Stephen got home from school, but that Mrs. Verdicchio never did so.

In June 1994, the Verdicchio family went on a cruise to Bermuda. During that time, *1050 Stephen appeared to be in great discomfort, crying in the night from the pain in his leg. On July 2, 1994, immediately after returning from vacation, Mrs. Verdicchio took Stephen to Dr. Ricca's office. The examination revealed swelling and firmness in the leg that felt "abnormal." Dr. Ricca told Stephen and Mrs. Verdicchio that he would order x-rays of Stephen's leg, and that he would wait for those results to decide how to proceed. He weighed Stephen at Mrs. Verdicchio's request, and found that the boy had lost five to seven pounds on the trip.

Mrs. Verdicchio testified that she insisted that Dr. Ricca give her the referral for the orthopedist so that she could at least make an appointment while they waited for the x-ray results. She told her husband that she "had to literally fight," ... "scream" ..., for a referral to an orthopedist. Mrs. Verdicchio ultimately obtained a referral from Dr. Ricca to see Dr. Bernard P. Murphy.

On July 7 Stephen was examined by Dr. Murphy, who reviewed the x-rays and found they revealed calcification in the quadriceps musculature as well as some calcification of the femur. Dr. Murphy ordered an MRI that was conducted on July 13, 1994, and revealed a mass in Stephen's leg. The doctor immediately advised the Verdicchios to take Stephen to the Thomas Jefferson Medical Center in Philadelphia for a biopsy. Stephen was first seen at Thomas Jefferson the next day and was diagnosed with osteosarcoma (a malignant tumor) of his left femur. It was also determined that the cancer had metastasized to Stephen's lungs.

Mrs. Verdicchio testified, over Dr. Ricca's objection, that on July 18, 1994, she called him and informed him that Stephen had been diagnosed with cancer and that the doctors at Thomas Jefferson needed Stephen's records, especially the most recent x-rays:

When I was talking to Dr. Ricca on the phone, his comment was that he had the x-ray and he had a copy of the tests and Stephen did not have cancer and I was to get him out of the hospital in Philadelphia and bring him home and he would deal with it at home.

Dr. Ricca acknowledged speaking with Mrs. Verdicchio that day but unequivocally denied that he made any of those statements. Maureen (Ginger) Mulligan, a co-worker of Mrs. Verdicchio, was permitted to testify that Mrs. Verdicchio called her, "hysterical," "sobbing" and "crying," and related the conversation in which she claimed Dr. Ricca denied that Stephen had cancer.

Stephen was hospitalized from July 14 to August 3, 1994. On July 17, a CAT scan was taken of Stephen's chest that revealed multiple metastatic nodules. Another CAT scan of his abdomen and pelvis taken on July 30 revealed further metastasis to his lungs and abdomen beyond that revealed on July 17. Stephen underwent surgical procedures to insert an intrafemoral artery catheter from his right leg to his left groin and into the cancer spot for the administration of chemotherapy, and was immobilized for about 14 to 20 days while he received treatment.

In November 1994, Stephen was hospitalized for six days and underwent a thoracotomy in an effort to arrest the spread of the cancer. In that surgical procedure, surgeons opened his chest and removed thirteen "wedge resections" containing metastatic tumors from many parts of the lung. In January 1995, Stephen was hospitalized for ten days and his left leg was amputated at the hip because he was suffering intractable pain secondary to the cancerous tumor that was unresponsive to medication.

In March of 1995, Stephen was admitted to Thomas Jefferson for the final time, *1051 with complaints of increased pain and voice change. Nothing more could be done for him medically, so he was discharged to his home on March 21, 1995. He died at home on May 3, 1995, believing that had his cancer been diagnosed earlier by Dr. Ricca, he might have been saved.

During trial plaintiffs offered Dr. Robert Morrow, a certified family physician, as an expert. Family medicine is a primary care specialty in which the physician serves as the first doctor of recourse when patients come with nonspecific or specific complaints for treatment or referral. Dr. Morrow reviewed the medical records maintained by Dr. Ricca from Stephen's visits during the period of time he was under Dr. Ricca's care, and noted that during the January 25, 1994, visit, Stephen indicated that he suffered some arthralgias—which means painful joints—of the knees. Dr. Morrow opined that Dr. Ricca deviated from the standard of accepted medical care on January 25, 1994, when he failed to examine the "extremities of a child who is complaining of pain in the knees, who is an athlete, who is ill. And Dr. Ricca should have done that at that time." Dr. Morrow explained,

when a young adult describes arthralgias of the knees they are describing pain below the waist. And the physical examination involves evaluation of those areas particularly where they say the pain is, in this case the knee. But usually in all the joints and structures connected with the knee.

Dr. Morrow further explained that such an examination is necessary because "it is very difficult for anyone, and in particular a child, to tell you precisely where discomfort is coming from. And they will give you usually a direction rather than a particular spot." Dr. Morrow continued:

[W]hen you mention knee arthralgias you're really talking about pain that is discerned as coming from that extremity. So, a proper examination involves looking at the patient.

....

You'll look at the relation of the joints to each other. You'll look at their back to see if there's any scoliosis. You'll examine the area of particular pain that you ask that patient to point to.

And you see whether there's any swelling, redness, heat or other abnormalities of that area. You'll check the joint to make sure the joint [sic] of the hip, the knee, the ankle are stable.

....

And that usually is a fairly, although it sounds like a long examination, is a fairly brief examination that takes about five minutes at the most, depending on the thoroughness.

When asked if such an examination would be relevant in a situation in which it appeared that many of the patient's problems were gastrointestinal, Dr. Morrow replied that in the context of a sick child who has lost

a tremendous amount of weight it is vitally important to pursue any lead that would explain the illness and the loss of weight. And in this particular case when the patient appears to be `seriously ill' to quote Dr. Ricca, it becomes vitally important to pursue the symptoms because they might provide an important clue as to the cause of a seriously ill child.

Dr. Morrow also testified that the white blood count could be associated with, among other things, cancer of the bloodline. He found elevated neutriphils levels and testified that that can result from stress or inflammation. He also testified that the uric acid level was "markedly elevated" and that that is "also found in tissue breakdown from tumors either of *1052 the bloodline like lymphoma or a leukemia or from solid tumors."

Dr. Morrow determined that Dr. Ricca should have followed up with Stephen after receiving Dr. Kern's report in March 1994:

Q: What should the primary care physician Dr. Ricca have done at that point in getting that letter?

A: The primary care physician is obligated to reevaluate the patient to find out why he is sick.

Q: Why is that doctor?

A: We have a profoundly ill child who presents with a weight loss of a substantial portion of his body mass but we do not have a diagnostic explanation for that. So, we must now proceed and find out why this is going on.

Dr. Morrow stated that at the May 3 visit, the standard of care required that Dr. Ricca order an x-ray or otherwise image the leg to determine the cause of the swelling, and possibly make a referral to an orthopedist if he did not have the expertise to evaluate the problem:

Q: What should have been done at this point?

A: The standard of care would be to delineate why the muscle was swollen and to determine the cause of that swelling.

....

Q: What do you do specifically?

A: You image the area in whatever technique will elucidate it. The simplest technique might be only a plain x-ray which might reveal the problem. Ordinarily one needs to do some more sophisticated imaging ... such as magnetic resonance imaging. Or they can refer it to a specialty to make that decision. But it is imperative that the area be diagnosed in terms of its cause or that close follow-up be entertained over a very short period.

....

Q: And in terms of referring to a specialist, tell us what you said about that.

A: If the primary care provider does not feel it's within their expertise to evaluate this kind of problem and to come to a conclusion as to its proper diagnosis and treatment then they should refer it to a specialist. And usually in bone which would be an orthopedist or a muscle specialist which is frequently also an orthopedist. But someone who has the sophistication to be able to establish a diagnosis and make a plan of treatment.

Later during direct examination, Dr. Morrow testified concerning Stephen's July 14, 1994, admission to the hospital and the ultimate diagnosis of his condition. Dr. Morrow stated that the diagnosis of Stephen's condition was "`Osteosarcoma, chondroblastic and osteoblastic high grade'.... Chondroblastic meaning it's chewing up the cartilage. And osteoblastic high grade meaning it's chewing up the bone.... It means a very malignant osteosarcoma which is a cancer." In addition, Dr. Morrow testified that during Stephen's stay at the hospital a CAT scan was taken of his chest and his abdomen, which revealed "multiple metastatic lesions, a cancer that had spread to the lung, in many places of the lung. And a few lymph nodes that were swollen and presumed to be also cancer spread in the abdomen."

Dr. Morrow was asked if he knew, within a reasonable degree of medical probability, when the cancer had metastasized to the lung, and he responded, "no, I do not." He indicated that there was no medical evidence that he had seen that could pinpoint when the cancer had spread to Stephen's lungs. Thereafter, the following colloquy took place:

Q: Now, we talked about the deviation in January of 1994. If the doctor *1053 had done what you say he should have done based upon good medical standards would Stephen be alive today?

A: The chances of him being alive at five years with the treatments available at that time were eighty-five percent (85%).

Q: What do you mean by eighty-five percent (85%)?

A: In large samples looked at in various countries including the United States the more current treatments for osteosarcoma have been remarkably successful in nonmetastatic disease.

Q: And by nonmetastatic you mean what?

A: Disease that's localized to its point of origin.

Q: And in this case what do you mean by that?

A: If his disease was diagnosed when it was localized to its point of origin his chances of survival by the most current studies, which looked at the cohort which would have included him, were eighty-five percent (85%).

Q: Do you have any opinion in terms of how long that mass had existed on his body?

A: I am confident from a review of the medical record and the laboratory studies that it was present in January in 1994.

On cross-examination, Dr. Morrow was asked what, in his opinion, Dr. Ricca would have found if he had examined Stephen's knees during the January 25, 1994, visit. Dr. Morrow concluded,

[s]ince Stephen was as described an asthenic child, he was tall and thin, he would have discovered an area on his leg of firmness and tenderness because of his muscles being so close to the skin. Without a big fat pad it would have been very easy to uncover at that point a mass.... On his lateral thigh.

Next, Dr. Morrow was questioned about the metastasis of Stephen's cancer. He conceded that at his deposition he testified that he had no opinion whether Stephen's cancer had metastasized as of May 1994 or as of January 1994. The following extended dialogue then took place:

Q: Now, you were asked some questions by Mr. Auerbach as to what you thought the percentage of possibility or probability was of Stephen having a cure if his osteosarcoma had been diagnosed in January of 1994. And I think you said eighty-five (85%) percent likelihood of a cure?

A: Of a five year survival.

Q: Yes. So let me see if we all understand that. You're not saying that if the osteosarcoma had been detected and treated in January of 1994 that Stephen would be cured for life, are you?

A: There's never a guarantee of that.

Q: Doctors talk in terms of five years. Am I correct?

A: That's the most accepted way of comparing studies.

Q: So, that the eighty-five percent (85%) means that he had an eighty-five percent (85%) chance of no recurrence of that cancer over a five year period.

A: Yes.

Q: Beyond that the percentages change, don't they?

A: The cohort that came through in the `90 to `94 time and has been analyzed, we're up to 1999, is as far as we've gone with this cohort. We won't know about 10 years for another four or five years.

Q: Okay. That opinion of yours and that estimate of percentages does not consider what would have happened if Stephen had metastasis, that is spread of the cancer, as of January 1994. Am I correct?

A: That is correct. At any point, yes.

*1054 Q: Or certainly May of 1994. You are not considering what chance of survival Stephen would have had if he had been diagnosed in May of 1994 had there been metastasis as of that time.

A: That question has not been posed to me.

Q: Well, if I pose it to you now do you have an opinion?

A: Yes.

Q: As to what the likelihood of his survival would have been in May of 1994 had there been spread of the cancer in May.

A: The numbers that I reviewed seemed to be over between 20 and 30 percent five years survival, perhaps a little higher.

Q: And would that depend upon where the cancer had spread to? That is what other part of the body?

A: There are a number or factors and that is one of them, yes.

Q: Cancer of the lung is a particularly grim situation for prognosis, isn't it?

A: Compared to?

Q: Cancer in some other part of the body?

A: Well, I would say bone marrow or brain would be worse. But it's not good.

At the conclusion of cross-examination, Dr. Morrow was asked when, in his estimation, Stephen first developed the osteosarcoma. Dr. Morrow responded,

Judging by the usual time to lung metastasis of 12 to 18 months I would postulate that when the weight loss began was probably the time when his body was responding to tumor and that was probably in the fall [of 1993]. It's also the cardinal manifestation of osteosarcoma that leads to diagnosis is pain. And so that's apparently when that pain was initiated, [in the fall of 1993].

On the defense case, as described above, Dr. Ricca testified to a starkly different version of his interactions with the Verdicchios than did Mrs. Verdicchio. He denied ever refusing or delaying referrals; denigrating Mrs. Verdicchio's relationship with her son; attributing Stephen's condition to anorexia or drugs; insisting that, as a runner, Stephen had to endure pain; refusing to accept the cancer diagnosis; or having any preconceived notions about Stephen's complaints. He also denied that he deviated in any way from the appropriate standard of medical care in his treatment of Stephen. On cross-examination the Verdicchios' lawyer was permitted to inquire of Dr. Ricca whether the Oxford Health Plan provided him with a financial incentive to minimize the number of referrals he made. Dr. Ricca denied any knowledge of such a bonus incentive at the time he was treating Stephen.

Dr. Stan Parman, a specialist in family and emergency medicine, testified on Dr. Ricca's behalf that Dr. Ricca had not deviated from the standard of care. Specifically he testified that because certain gastrointestinal problems can result in joint pain, it was not unreasonable for Dr. Ricca not to examine Stephen's knees given that his primary complaint was intestinal problems. Dr. Parman testified that Stephen's white blood count in January 1994, while suggestive of some type of infection, was nonspecific and neither the white blood count nor the slightly elevated neutriphils would be indicative of a tumor. He also testified that the uric acid level was within normal limits. On cross-examination, Dr. Parman acknowledged that in his report he stated that "one could postulate that Stephen could have been saved if only the diagnosis had been made earlier." When further questioned, he explained that that was a generic argument that could be made for all diseases; the sooner it is found, the better the chance of survival.

*1055 Dr. Arnold Rubin, a board certified specialist in internal medicine and hematology with a subspecialty in oncology also testified on behalf of Dr. Ricca. He conceded that Dr. Ricca should have examined Stephen's knee during the January 25, 1994, visit and that not doing so was a deviation. Dr. Rubin indicated that Stephen's uric acid level in January 1994 was normal and had no connection to Stephen's osteosarcoma. Dr. Rubin stated that as between diagnosis in May or July 1994, Stephen's "care and treatment" would have been the same. However, Dr. Rubin could only state that, had the cancer been discovered in January 1994, Stephen's "ultimate outcome" would have been no different. Dr. Rubin acknowledged that in order for Stephen to have developed "an extensive disease such as that was observed in July of 1994 it would have taken probably about six months to a year."

III

The Verdicchios' fundamental argument is that the holdings of the trial court and the Appellate Division that "it was incumbent upon plaintiff to prove through expert testimony that the osteosarcoma had not metastasized by January 25th" violate the principles established in Evers, Scafidi and Gardner.

Dr. Ricca counters that the Verdicchios failed to elicit competent medical evidence to support the conclusion that the deviation increased Stephen's risk of harm from the preexisting condition or that that increased risk was a substantial factor in bringing about the results complained of. Dr. Ricca also contends that it was the Verdicchios' burden to establish which pain and suffering damages were caused by his negligence and which resulted from the underlying disease and that they failed to do so.

Dr. Ricca's cross-petition seeks to avoid reinstatement of the verdict in the event of a reversal and urges a new trial because of what he characterizes as prejudicial and inflammatory evidence that poisoned the verdict. He also repeats his claim that the verdict cannot stand because the Verdicchios failed to prove which of their damages resulted from Dr. Ricca's negligence and which were consequences of the underlying disease.

The Verdicchios respond that the issues raised in the cross-petition procedurally are barred because, although they were fully briefed in the Appellate Division, they were not the basis of a protective cross-appeal. On the merits, they argue that the challenged evidence properly was admitted as shedding light on Dr. Ricca's attitude toward the case and on the parties' dramatically different versions of their interactions. At most, the Verdicchios claim the evidence was harmless error. The Verdicchios also counter that Dr. Ricca's damages apportionment argument is meritless because it was his obligation to prove that apportionment was possible— an obligation that he failed to meet.

IV

The issue in the case is precisely focused. Both the trial court and the Appellate Division concluded that because plaintiffs failed to "prove" that Stephen's cancer had not metastasized in January of 1994, the initial point of alleged malpractice, they could not sustain the burden in an "increased risk case" under Evers, Scafidi and Gardner. To assess that conclusion, the relevant legal principles require disquisition.

A.

A medical malpractice case is a kind of tort action in which the traditional negligence elements are refined to reflect the professional setting of a physician-patient relationship. Thus, a plaintiff in a *1056 malpractice action must prove the applicable standard of care, Rosenberg v. Cahill, 99 N.J. 318, 492 A.2d 371 (1985); that a deviation has occurred, Clark v. Wichman, 72 N.J.Super. 486, 179 A.2d 38 (App.Div. 1962); and that the deviation proximately caused the injury, Germann v. Matriss, 55 N.J. 193, 260 A.2d 825 (1970).

As a general rule, it is the causation element that is the most complex. There are different tests for determining proximate cause. For example, the traditional "but for" test that applies in most negligence settings "allow[s] recovery only when the injury is one that would not have occurred `but for' the wrongful act." J.D. Lee & Barry A. Lindahl, Modern Tort Law: Liability & Litigation § 4.03 (West Group 2002); Conklin v. Hannoch Weisman, 145 N.J. 395, 417, 678 A.2d 1060 (1996); Evers v. Dollinger, 95 N.J. 399, 415, 471 A.2d 405 (1984); Vuocolo v. Diamond Shamrock Chemicals Co., 240 N.J.Super. 289, 295, 573 A.2d 196 (App. Div.), certif. denied, 122 N.J. 333, 585 A.2d 349 (1990). However, the "but for" test has its limitations in situations where two or more forces operate to bring about a certain result and "any one of them operating alone would be sufficient." Modern Tort Law § 4.03. Indeed, the "but for" test has been characterized as a potentially "insurmountable obstacle" for a plaintiff in a case in which "unrelated factors may have contributed to the same injury." Diane Schmauder, An Analysis of New Jersey's Increased Risk Doctrine, 25 Rutgers L.J. 893, 895 (1994).

In response to the apparent limitation of the "but for" test in concurrent causation cases, New Jersey, like many jurisdictions, has adopted a modified standard—the substantial factor standard—"limited to that class of cases in which a defendant's negligence combines with a preexistent condition to cause harm—as distinguished from cases in which the deviation alone is the cause of harm." Battenfeld v. Gregory, 247 N.J.Super. 538, 549, 589 A.2d 1059 (App.Div.1991)(citing Scafidi, supra, 119 N.J. at 108-09, 574 A.2d 398).^[3]

The substantial factor test allows the plaintiff to submit to the jury not whether "but for" defendant's negligence the injury would not have occurred but "whether the defendant's deviation from standard medical practice increased a patient's risk of harm or diminished a patient's chance of survival and whether such increased risk was a substantial factor in producing the ultimate harm." Gardner v. Pawliw, supra, 150 N.J. at 376, 696 A.2d 599. Once the plaintiff demonstrates that the defendant's negligence actually increased the risk of an injury that later occurs, that conduct is deemed to be a cause "in fact" of the injury and the jury must then determine the proximate cause question: whether the increased risk was a substantial factor in bringing about the harm that occurred. Conduct is a substantial factor if it would

lead the trier of fact, as a reasonable person, to regard it as a cause, using that word in the popular sense. Under the "substantial factor" test, the defendant's negligence need not be the sole or primary factor producing the injury; it need only be a substantial factor. Thus the test covers the situation where there may be several substantial factors contributing to the same result.

[Modern Tort Law § 4.03, 4-4 (citations and internal quotations omitted) ]

The Restatement of Torts § 431 explains that

[t]he word "substantial" is used to denote the fact that the defendant's conduct *1057 has such an effect in producing the harm as to lead reasonable men to regard it as a cause, using that word in the popular sense, in which there always lurks the idea of responsibility, rather than in the so-called "philosophic sense," which includes every one of the great number of events without which any happening would not have occurred.

[Restatement § 431 (comment a).]

In other words, merely establishing that a defendant's negligent conduct had some effect in producing the harm does not automatically satisfy the burden of proving it was a substantial factor:

Some other event which is a contributing factor in producing the harm may have such a predominant effect in bringing it about as to make the effect of the actor's negligence insignificant and, therefore, to prevent it from being a substantial factor. So too, although no one of the contributing factors may have such a predominant effect, their combined effect may, as it were, so dilute the effects of the actor's negligence as to prevent it from being a substantial factor.

[Restatement § 433 (comment d).]

Our model jury charge reflects the same notions. Model Jury Charges (Civil) § 5.36E (2002).

B.

A review of our case law reveals the way in which the substantial factor test has been applied in increased risk cases. In Evers, supra, plaintiff alleged that her physician neglected to perform appropriate diagnostic tests on a lump and bleeding sore in her breast that would have revealed breast cancer. At the time of trial, Mrs. Evers had taken no medication and had received no chemotherapy or radiotherapy, nor had she experienced a recurrence of the cancer. She claimed that the seven-month delay in diagnosis caused her "both physical and emotional injury" and increased the risk that the cancer would recur. 95 N.J. at 404, 471 A.2d 405.

The trial court did not allow Mrs. Evers' experts' testimony into evidence because the experts "were unable to quantify the increased risk of recurrence of cancer" and thus entered a judgment for the physician. Id. at 405,