On the growth rates of human malignant tumors: Implications for medical decision making

Abstract

Testicular carcinomas, pediatric tumors, and some mesenchymal tumors are examples of rapidly proliferating cell populations, for which the tumor volume doubling time (TVDT) can be counted in days. Cancers from the breast, prostate, and colon are frequently slow‐growing, displaying a TVDT of months or years. Irrespective of their growth rates, most human tumors have been found: to start from one single cell, to have a long subclinical period, to grow at constant rates for long periods of time, to start to metastasize often even before the primary is detected, and to have metastases that often grow at approximately the same rate as the primary tumor. The recognition of basic facts in tumor cell kinetics is essential in the evaluation of important present‐day strategies in oncology. Among the facts emphasized in this review are: (1) Screening programs. Most tumors are several years old when detectable by present‐day diagnostic methods. This makes the term “early detection” questionable. (2) Legal trials. The importance of so‐called doctor's delay is often discussed, but the prognostic value of “early” detection is overestimated. (3) Analyses of clinical trials. Such analysis may be differentiated depending on the growth rates of the type of tumor studied. Furthermore, uncritical analysis of survival data may be misleading if the TVDT is not taken into consideration. (4) Analyses of epidemiological data. If causes of malignant tumors in humans are searched for, the time of exposure must be extended far back in the subject's history. (5) Risk estimations by insurance companies. For the majority of human cancers, the 5‐year survival rate is not a valid measurement for cure. Thus, basic knowledge of tumor kinetics may have important implications for political health programs, legal trials, medical science, and insurance policies. J. Surg. Oncol. 1997;65:284–297. © 1997 Wiley‐Liss, Inc.

Cancer metabolism and the dynamics of metastasis

“…2, we consider here the case of prostate cancer, whose specific characteristic parameters are well documented in the literature [18] and have been employed in [19] (10) Assuming for the prostate a metabolic power of 0.2 W (17000 J/day), we find that metastasis starts at a critical time of about two or three weeks after a malignant transformation of the parental tumor. However, since t* depends on P 0 ( ) 1 3 , its dependence on the intrinsic metabolic power of the organ is rather weak.…”

“…corresponding to the preclinical phase, the threshold of clinical diagnostics [18], and the clinical phase where the evolution of the tumor should be studied (since the preclinical evolution is simply a matter of extrapolation).…”

“…There are tumors that develop over a long time frame, with years between diagnosis and lethal stage (among them some types of lung cancer [18]), (see Fig. 3).…”

High rates of tumor growth and disease progression detected on serial pretreatment fluorodeoxyglucose‐positron emission tomography/computed tomography scans in radical radiotherapy candidates with nonsmall cell lung cancer

“…If treatment is delayed the probability of survival may be reduced. 4,7,[10][11][12][13] A limited number of serial pretreatment imaging studies have been undertaken in NSCLC patients who are candidates for potentially curative therapy. In a significant study, O'Rourke and Edwards reported that 21% of 29 candidates for radical RT developed incurable disease progression (median 54 days) between diagnostic/ staging and RT planning computed tomography (CT) scans.…”

Screening computed tomography

“…15 In a case series of 40 incidentally detected primary solid renal tumors that were monitored with serial CT, most tu- ca: carcinoma. a The three tested incidence rates are those of the U.S. population of ages 60-64 years, 65-69 years, and 70-74 years adjusted for the gender distribution of the study population.…”