Residual tumor resection (RTR) in advanced testicular cancer: Indication, outcome and prediction of histology

Abstract

4645 Background: RTR following inductive chemotherapy for advanced testicular cancer is an essential part of the interdisciplinary multimodality treatment. Since RTR is a challenging surgical procedure, aim of our study was to develop a clinically reliable model for identification of a low risk group in which RTR could be safely omitted. Methods: RTR was performed in 85 pts after first-line chemotherapy with all pts showing normalized tumor markers. In a retrospective analysis > 15 pre-RTR parameters including immunohistochemical expression of mdr-1 in the orchiectomy specimens were assessed to predict necrosis/fibrosis or teratoma in residual tumors. Statistical analysis was performed by uni- and multivariate analysis, parameters were statistically significant if p<0.05. Results: 56 pts (67.5%) had necrosis/fibrosis, 17 (20.5%) and 10 pts (12%) had mature teratoma and vital cancer in the RTR specimens, resp. After multivariate analysis only pre-chemotherapeutic AFP levels and tumor size before RTR were independent predictors of necrosis. However, positive predictive values were only 74% and 76%, resp., sensitivity was 81% and 52.8%, resp., specificity was 59% and 79.3%, resp. Of pts with <2cm residual masses 6 had vital cancer /mature teratoma, of pts with < 15ng/ml AFP 9 had vital cancer/mature teratoma. Mature teratoma in the orchiectomy specimen was associated with a 86% risk for teratoma in the residual mass whereas non-teratomatous components in the primary cancer had a 47% risk to harbour teratoma in the RTR specimen p<0.001). High mdr-1 expression in the orchiectomy specimen correlated with vital cancer/teratoma in the RTR specimen or with recurrences in pts with necrosis in the RTR specimen. Conclusions: Although pre-chemotherapy AFP levels < 15ng/ml and a residual mass < 2cm are associated with a favourable histology in the RTR specimen, an individual histology cannot be predicted. All pts with nonseminomatous germ cell tumors and residual masses need to undergo RTR. Mdr-1 expression in the orchiectomy specimen might turn out to be a valid clinical marker for unfavourable histology or early recurrences. No significant financial relationships to disclose.