Patients with poor-prognosis testicular cancer have a better chance of surviving if they are treated at an institution that cares for five or more such patients during an approximate 4-year period than if treated at an institution that sees fewer than five patients during the same period. The study was published by Laurence Collette, msc, of the European Organization for Research and Treatment of Cancer (EORTC), and colleagues, in the May 19th issue of the Journal of the National Cancer Institute.
Investigators analyzed data on 380 patients treated between 1990 and 1994 in a randomized, phase III trial conducted by the EORTC and the Medical Research Council of the United Kingdom. The 380 patients received treatment at one of 49 participating institutions in 11 countries. These institutions were classified according to the total number of patients that they entered into the studyfewer than 5 (26 institutions), 5 to 9 (7 institutions), 10 to 19 (12 institutions), or 20 and more (4 institutions). The main end point for analyzing the effect of the treating institution was overall survival.
Risk of Death Almost Double
The risk of death among patients treated at the 26 institutions enrolling fewer than five patients was almost double the risk observed in the 23 institutions treating five or more patients (hazard ratio, 1.85; 95% confidence interval, 1.16 to 3.03). In addition, 13% of the patients treated in centers enrolling fewer than five patients died of treatment-related causes, compared with 6% of patients treated in institutions that entered larger numbers of patients.
According to the authors, the poorer results at centers enrolling fewer than five patients stem from a combination of factors. These include a greater tendency to reduce the dose of chemotherapy and to delay treatment cycles, and the greater possibility that surgery to remove residual lesions would not be performed at these institutions. The combined impact of these factors is clinically important, and in this analysis, the treating institution appears to be as strong a predictor of survival as the patients disease status at study entry. However, a prospective study is needed to confirm these results.
Results Characterized as Discouraging
In an editorial, Eric Feuer, PhD, of the National Cancer Institute, and Joel Sheinfeld, MD, and George Bosl, MD, both of Memorial Sloan-Kettering Cancer Center, note that the results of this study are discouraging given the high cure rate for testicular cancer and the widespread knowledge of treatment success. They cite other studies that have also shown a positive association between patient outcome and number of patients treated, and they describe some cautions necessary in interpreting these studies.
The editorialists conclude that, in the case of relatively rare cancers, such as germ cell tumors, it is difficult for centers to accrue the critical mass of patients needed to allow physicians to become expert in managing the disease, and that patients should be treated by experts to ensure the highest cure rate.