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

Background: Because metastatic nonseminomatous germ cell cancer is a rare b ut treatable cancer, we have explored whether there is an association betwe en the experience of the treating institution with this disease and the lon g-term clinical outcome of the patients, particularly patients with a poor prognosis. Methods: We analyzed data on 380 patients treated in one of 49 i nstitutions participating in the European Organization for Research and Tre atment of Cancer/ Medical Research Council randomized trial of four cycles of bleomycin-etoposide-cisplatin followed by two cycles of etoposide-cispla tin versus three cycles of bleomyein-vincristine-cisplatin followed by thre e cycles of etoposide-ifosfamide-cisplatin-bleomycin, both treatment regime ns given with or without filgrastim (granulocyte colony-stimulating factor) . Institutions were divided into four groups based on the total number of p atients entered in the trial, The groups were compared by use of the Cox pr oportional hazards model stratified for treatment with filgrastim and for p atient prognosis as defined by the International Germ Cell Consensus Classi fication Group. With the use of this classification, only 65% of the patien ts had a poor prognosis. Results: Patients treated in the 26 institutions t hat entered fewer than five patients into the trial had an overall survival that was statistically significantly morse (two-sided P = .010; hazard rat io = 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 surviva l 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 s urgery for residual masses, although only the differences in dose intensity achieved statistical significance. Conclusions: Patients treated in instit utions that entered fewer than five patients into the trial appeared to hav e poorer survival than those treated in institutions that entered a larger number of patients with "poor-prognosis" nonseminoma.