Impact of the treating institution on survival of patients with "poor-prognosis" metastatic nonseminoma

Background: Because metastatic nonseminomatous germ cell cancer is a rare but treatable cancer, we have explored whether there is an association between the experience of the treating institution with this disease and the long-term clinical outcome of the patients, particularly patients with a poor prognosis. Methods: We analyzed data on 380 patients treated in one of 49 institutions participating in the European Organization for Research and Treatment of Cancer/ Medical Research Council randomized trial of four cycles of bleomycin-etoposide-cisplatin followed by two cycles of etoposide-cisplatin versus three cycles of bleomyein-vincristine-cisplatin followed by three cycles of etoposide-ifosfamide-cisplatin-bleomycin, both treatment regimens given with or without filgrastim (granulocyte colony-stimulating factor). Institutions were divided into four groups based on the total number of patients entered in the trial, The groups were compared by use of the Cox proportional hazards model stratified for treatment with filgrastim and for patient prognosis as defined by the International Germ Cell Consensus Classification Group. With the use of this classification, only 65% of the patients had a poor prognosis. Results: Patients treated in the 26 institutions that entered fewer than five patients into the trial had an overall survival that was statistically significantly morse (two-sided P = .010; hazard ratio = 1.85; 95% confidence interval 1.16-3.03) than that of patients treated in the 23 institutions that entered five patients or more. Overall survival and failure-free survival were similar among institutions that entered at least five patients. The observed effect may be related to differences in adherence to the chemotherapy protocol and in the frequency and extent of surgery for residual masses, although only the differences in dose intensity achieved statistical significance. Conclusions: Patients treated in institutions that entered fewer than five patients into the trial appeared to have poorer survival than those treated in institutions that entered a larger number of patients with "poor-prognosis" nonseminoma.