Cervical Cancer Cases
Understanding the Tumor Doubling Defense

The growth of a tumor mass inevitably results in the mass doubling in size over time. Experts defending delay in diagnosis of cancer cases have used this seemingly innocent and logically necessary, though irrelevant, observation over the last twenty years to lead juries to ignore common sense and find that the negligent failure to have earlier diagnosed cancer was meaningless because the death or morbidity was inevitable. It is the object of this article to examine this defense and demonstrate its fallibilities.

A primary tumor starts from a single cell. This first tumor cell multiplies geometrically over time. Assuming the cell and its progeny survive, the number of cells present increases by a factor of two, between generation from 1 to 2-4-8-16-32, and so forth.

In fact, the increase in the number of cells present in a given tumor depends on the percentage of cells proliferating, the cell cycle time of those cells that do proliferate and the fraction of tumor cells that do not survive. The net growth of the tumor volume will remain reasonably exponential only if one presumes that these factors remain constant.1 This presumption is demonstrably false with respect to metastases and at different parts of the growth cycle.

In virtually every trial where the tumor doubling time defense is raised, an exhibit in the form depicted in figure 1 is presented:

Such an exhibit hopes to persuade jurors to think of a very small tumor of, for example, .2 cm. to 1 cm. in diameter as having great malignant potential far out of proportion to its size. For example, a 1 cm. tumor contains 109 (1 billion) cells. Figure 1 presupposes that the tumor cells having a diameter of 10 µm require 32 cell divisions to acquire a 1 cubic cm. mass containing 109 cells. Note, that if one assumes the tumor cells are 25 µm in diameter, 26 doublings would be required to reach the same volume but would contain 1/64th as many cells or about 15,000,000 as opposed to 1,000,000,000.

Of course, the difference between 15,000,000 and 1,000,000,000 cells is not particularly relevant unless the number of cells present impacts upon the clinical treatment of the cancer and its prognosis, if earlier treated. As early as 1981, Spratt, a leading proponent of the tumor-doubling defense, urged that cancer therapy could make no difference once a tumor has reached 9 doublings.2 That is, Spratt would have a jury believe a tumor containing 512 cells had metastasized with unavoidable fatal consequences.

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