Forensic, General & Medical
Expert Witnesses

Extremism in Defense of Physicians is No Vice, Just Junk Science


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In nearly every meritorious missed cancer case there comes a time when the defendant’s attorney, losing on the facts, considers use of The Doubling Time Defense. By that time, the Plaintiff has already shown beyond doubt that the defendant physician had a Duty to take care of the patient and that there probably was a Breach of the Standard.

The patient, dying, is eloquent about their predicament and communicates well and strongly to the Jury in her video deposition. In all - a fairly strong set of facts for the Plaintiff.

Making matters worse, the Insurance Company has a new directive and it is disinclined to settle suits; they want all Defendants to opt for Trial. Faced with a long delay in the diagnosis of this cancer and, with a seeming change in the Stage of the cancer during that delay, Defendant’s recourse is to find a medical expert who will present the Doubling Time Defense to convince the Jury that the delay made no difference in outcome for the patient. The expert will opine that the number of lymph nodes involved with cancer, or the metastasis later found, were already present at the time of the alleged Breach of the Standard of Care. Therefore, the patient’s stage didn’t change and no harm flowed from the delay. As a basis for their argument they employ The Doubling Time Defense, an example of “junk science” promoted by very well credentialed physicians for the defense. As all false testimony in court, it can change the outcome of litigation and therefore should be strictly prohibited.

Lawsuits, despite some detours, are rather orderly affairs. The rules are very strictly set, largely unchanging or unchangeable. Yet, medical malpractice lawsuits can be very volatile procedures. There are many physicians who will only assist a physician-defendant and never a worthy Plaintiff. Indeed, hospital credentials’ committees and medical boards have considered censuring physicians for daring to help a patient (now a plaintiff) who has been, in the doctor’s opinion, subjected to inferior and harmful care.


Unlike the Defense, cases brought by Plaintiff’s are discretionary, that is, they go forward based on the merits of the case. If the case satisfies the four required elements of the Tort of Medical Malpractice: The (1) Duty of the Defendant to be responsible for the care of the patient (now Plaintiff or Decedent), (2) an act or omission outside the accepted Standard of Care, (3) a Damage that occurs and (4) a legal connection (called “Causation”) between the Breach of the Standard and the Damages claimed, then the case has “merit.” In practical terms, a “good” case that should be winnable based on the material presented.

Presumably, the Plaintiff’s attorney should know very early in their inquiry into the matter if they can pass the Four Tests of the Tort of Medical Malpractice.

On the other side, the defendants’ involvement in a case is not discretionary but mandatory; their attorneys MUST defend them regardless of the situation. This, of course, leads to some problems. A Defendant, faced with a meritorious case is presumably fighting a battle that they should lose. Incredulously, attorneys do defend these cases and, mirabile dictu, find expert physicians who are willing to go to bat for the Defendant, despite the factual reality.

Although defense attorneys present their cases as representing the best science, in missed cancer cases the appearance of science may replace good science. This is Junk Science, and if the Jury relies on this to make decisions, justice isn’t served.

As an illustration, let’s take a closer look at a meritorious missed cancer diagnosis case to demonstrate this problem with expert testimony.

In July of 1990, a 48-year-old woman sees her physician because of breast tenderness. Physical examination is not helpful and a mammogram is done. Although showing abnormalities on later review, it is deemed “Normal” by the mammographer. In January of 1992, the patient is diagnosed with breast cancer in the same area complained about in 1990. A new mammogram shows progression of the non-diagnosed abnormality present in 1990. A modified radical mastectomy is done with the finding of about a 3 cm. primary lesion with a positive node about 1 cm. Because of the 18-month delay of diagnosis, the patient sues her physician(s).

The defense employs a medical expert who mounts the Doubling Time Defense to “prove” that the life-limiting metastasis had occurred long before any breach of the standard. By so doing they free the physician of any responsibility for the outcome. The expert’s testimony is summed up in Figure 1. The defendant’s expert uses published growth rates for clinically visible tumors, and calculates the number of “doublings” of the first and subsequent cancer cells to achieve the size of the primary and/or the lymph node metastasis. In our example, the ”expert” uses a 90-day doubling time and plots this on the graph extrapolating back from the size of the primary. Multiplying the number of doublings of the original cancer cell needed to make a lump of the size found by the doubling time, the expert retrospectively fixes a “date certain” for the time of the life-limiting event (here, lymph node involvement). If the defendant can prove that the metastasis was present before the time of the alleged negligent act or omission then no damages can attach to the defendant. A straight line on a graph is a simple to understand solution that is easily accepted by jurors. Here the expert “proves” that the primary tumor started in December of 1982, the lymph node metastasis occurred in March of 1984. [This expert also calculates that the mastectomy site recurrence to have occurred in June of 1987, about five years before the mastectomy was done!]

The Doubling Time argument used by Defendant’s experts is so seemingly certain that it is difficult to disbelieve the defendant’s experts testimony unless you have more information than the expert is willing to share. Because the jury knows nothing about cancer growth, the expert can give fictional testimony and be convincing because of the factors of impressive credentials along with carefully crafted testimony and the seeming security of a straight line drawn on a graph. It is an explanation of science that is understandable and easily remembered by jurors.

Nonetheless, it is well established in cancer literature that cancers do NOT grow as a straight line, but rather by Gompertzian kinetics. (Named after an actuary of the late 19th Century who devised these curves for purposes of population analysis). Gompertzian growth is a universal “constant” that applies to all biologic systems. (See Figure 2). First, there is a period of exponential growth and later, because of problems with oxygenation, nutrition, genetic heterogeneity and other factors, growth constantly slows. The asymptotic (retarded growth rate) portion of the growth curve occurs during the clinically visible phase of cancer. These are the growth rates that can be found in the literature (although most doubling time defense experts use about a 100-day doubling time). Some data is available that may indicate that t growth is not strictly Gompertzian, but “sporadic” or ”intermittent”. In any case it is not linear. For instance, Figure 3 demonstrates the growth and turbidity curves for an in vitro bacterial culture showing the same retardation of growth rate as the culture grows larger.

Almost all cancers are in a retarded growth phase by the time they are visible and therefore the calculation is not representative of the entire growth of the cancer. Note in Figure 2 that if the slope (e.g., growth) of the curve from “A” to ”B” is extrapolated retrospectively it leads to unscientific conclusions about the time of origin of the tumor, metastasis or other life-limiting event.

Figure 4 demonstrates the growth of an implanted tumor. Note how the same shaped curve is obtained. Here, we know the exact date of the implantation. Yet employing the measured rate of growth (doubling time) in the visible phase and applying it to the entire growth of the cancer it can be “calculated” that the cancer started long before the experiment commenced.

An obvious example of Gompertzian growth is pregnancy as shown in Figure 5. Note the doubling time of the fetus during the last trimester. Applying this growth rate to the fetus and calculating the number of doublings of the fertilized ovum (more than 30) to attain this size leads to unphysiologic conclusions about the date of conception.

Indeed, a Gompertzian curve describes all growth and has been published (see Figure 6).

Doubling time calculations lead to bizarre results: for example, calculate your “doubling time” as a child: choose any two convenient points in your history, such as when you weighed 50 and then 100 pounds (or 25 and 50, or any other weights during your growth). A 100-pound person is the result of more than 40 divisions of the fertilized ovum. The average “doubling time” from 50 to 100 pounds takes about five+ years. Multiplying 40 divisions times 5 years per “doubling” we reach the ridiculous conclusion that the 100-pound child is more than 200 years old!

Use of the Doubling Time Defense is roughly equivalent to clocking a car driving down the street and using its current speed to determine when it left its garage.

Unfortunately, Gompertzian kinetics, although applicable to tumor growth cannot be extrapolated retrospectively either! ”Doubling Time Defense” cannot be used because a straight line does not describe growth. Gompertzian calculations cannot be used because an infinite number of Gompertzian curves can be drawn through a point.

Defense experts conveniently “forget” about Gompertzian growth or disavow its relevance. The straight-line calculation of tumor growth, used to fix the time of origin of a tumor or metastasis, is inaccurate, misleading and false.

Current literature is consistent in ignoring or refuting the use of doubling time for this purpose: DeVita, et al. in early editions (up to the 4th) of Cancer: Principles and Practice of Oncology had an entry for ”doubling time” in the index - it has been removed in the last few editions of this classic text. In the second edition (1985) at page 7 Doubling Time is discussed: ”It is important when the physician attempts to extrapolate from doubling times in the clinic to preclinical circumstances in order to estimate the time the tumor growth started. Such extrapolations are almost certainly erroneous and tend to overestimate the tumor lifespan in the preclinical period. In the extreme case, it may be calculated that tumors begin before conception.”

DeVita, et al. in its latest edition (7th) states at p. 301: ” . . . . .the growth of most solid tumors follows a pattern of gompertzian kinetics. In this setting, the growth of cells is significantly faster in the early part of the growth curve than at any other stage in the growth kinetics.”

Cancer Medicine 6 (Holland & Frei) mentions Gompertzian growth with approval (Chapter 43 - Cytokinetics at p. 659).

The American Cancer Society Textbook of Oncology (1991) at p.50 notes: “Calculations made using tumor-doubling times obtained from measurements in patients would lead to the conclusion that the tumor must have started 10 to 20 years prior to its detection. Such calculations are fundamentally flawed.”

J. Spratt, who has spent much time and research effort on the issue of cancer growth concludes: ”Growth rates in the pre-detectable period are estimated to be much faster than those that occur with grossly measurable breast cancers in keeping with the prediction of Gompertzian growth.” In a further paper he wrote: ”The current analysis provides evidence that breast cancer growth can be modeled better by decelerating growth laws than by the exponential equation.” Spratt’s Cancer of the Breast in its second (1979 at p. 217) and 4th editions (1995 at p. 343) notes: ”Multiple events occur continuously in the life of a cancer, and the net effect reflects the interaction of these variables. The slopes [sic] of the growth curve mirror the net effect of many variables; they also reflect the changing relationship that may occur among these variables with the growth of cancer. Therefore, if attempts are made to extrapolate growth curves beyond the extent of observed data, the extrapolator is in an unknown realm and his interpretations are subject to serious error.” [Emphasis added]

The Doubling Time Defense is not generally accepted in the medical community, and there are no generally accepted competing models to Gompertzian. Among Medical Oncologists, doubling time is not accepted, used or calculated and, in a survey, 98% of oncologists do not use doubling time.


Harris stated: ”There are deficiencies, however, in the concept of exponential tumor growth. In fact, for breast cancer and other epithelial malignancies, tumor growth is better described by a Gompertzian rather than exponential (straight-line) model. In the Gompertzian model, the growth constant is exponentially slowing. Therefore, while the tumor mass increases in size, its doubling time becomes progressively longer. In vitro and in vivo studies have indicated that the human tumor cell cycle time is on the order of two days, not 100 days.”

Legal Considerations

At law there are two cases that define admissibility of expert testimony: Frye [D.C. Cir. 1923. 293 F 1013] and Daubert v. Dow [113 S.Ct. 2786, 1993]. Each of the States follows one or the other rule. Frye requires that expert testimony be ”generally accepted” by the medical community. Daubert includes ”general acceptance” but adds and expands this rule with three more ”tests”: (1) has the opinion been, or can it be, tested? (2) Has the technique or theory been subjected to peer review and publication? (3) Is the rate of error known and are there standards controlling the operation of the calculations?

Given the overwhelming biologic evidence for Gompertzian growth the Doubling Time Defense cannot pass the tests of Daubert and does not meet the Frye standard. Yet, the Doubling Time Defense is regularly employed in missed cancer cases across the USA with hardly any legal or scientific objections from Plaintiffs. What is more unsettling is that the purveyors of this ”Junk Science” are prominent physicians, including some holding named chairs at major medical centers.

The biologic import of defendant’s experts’ testimony means that there can never be early diagnosis of cancer. The expert finds, in all cases, that metastasis, local or distant, occurred before the physician arrived on the scene.

Juries are easily swayed by this argument. Therefore, it is essential that a motion to exclude the ”Doubling Time Defense” should be heard by the Judge. A clear presentation and a Jurist who listens and analyzes can banish this Junk Science from the Courts. Recently a Judge in Florida granted such a motion.

The ”Doubling Time Defense” is in opposition to the recommendations of the American Cancer Society, the National Institutes of Health, the National Cancer Institute and other reputable bodies who have stated opinions of the value of early diagnosis of cancer. The Doubling Time Defense contradicts this underlying public policy recommendation for the early detection of cancer. Early diagnosis of most cancers means a higher cure rate. In contrast, the proponents of Doubling Time find that cancer is always diagnosed too late and is never curable. Simple examination of the voluminous cancer literature shows this to be untrue. Indeed, these expert opinions are only given during a legal proceeding and never voiced in the clinic, hospital, or at the bedside.

There is a standard of care for physician-experts in and out of the courtroom and that is, to tell the truth. If an expert opines falsities or obfuscations, they should be held accountable for their intentional acts. The scientific and legal records are clear. Experts should be considered aware of the latest scientific data. Therefore, the proponents of the Doubling Time Defense must be held to the presumption that they know their testimony is false.

In 1998, the AMA House of Delegates voted that medical-legal testimony should be considered part of the ”practice of medicine” and therefore should be subject to peer review. I agree, it’s time to clean up the mess in medical-legal testimony by fairly and evenhandedly examining ALL testimony be it for Plaintiffs or Defendants and carefully identifying, isolating, exposing, and correcting those who breach the “Standard of Care” in the practice of Legal Medicine.

Figure 1: Work sheet used by Doubling Time Defense Expert. Note that the calculations show that the mastectomy site recurrence occurred over four years before the operation was done.

Figure 2: The Gompertzian growth curve. During the early stages of its development, a tumor’s growth is exponential. However, as a tumor enlarges, the growth slows. By the time a tumor becomes large enough to cause symptoms and be clinically detectable, the majority of its growth has already occurred and is no longer exponential.

Figure 3: Growth curves as determined by turbidity and viable counts. Broth cultures of E. Coli for viable counts (Curve A) and at the same time, turbidities were determined at 530 nm (Curve B) [Source - World Health Organization]

Figure 4: Growth Curve of Experimentally Implanted Tumor Cells

Figure 5: Growth Curve of fetus and its’ instantaneous doubling time calculated from known data. [Also showing two other growth curves: - children and leukemia.]

Figure 6: The Universal Growth Curve




Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.For specific technical or legal advice on the information provided and related topics, please contact the author.

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