Resection of residual retroperitoneal masses in testicular cancer: evaluation and improvement of selection criteria. The ReHiT study group. Re-analysis of histology in testicular cancer.

Residual retroperitoneal masses may remain after chemotherapy for metastatic non-seminomatous testicular cancer, which harbour residual tumour or totally benign tissue (necrosis/fibrosis). These residual masses may be effectively removed by a surgical resection. We evaluated current selection criteria and tried to develop alternative criteria in a data set of 544 patients, who had retroperitoneal lymph node dissection of residual masses. Six resection policies were identified from the literature. Two alternative policies were developed with logistic regression analysis. Evaluation of the policies focused on the true-positive rate (resection in case of tumour), and the false-positive rate (resection in case of necrosis). It appeared that most current policies use the size of the residual mass (> or = 10 mm or > or = 20 mm) as the predominant selection criterion. This resulted in high true-positive rates (most > 90%), but false-positive rates between 37% and 87%. The alternative policies included five well-known predictors of necrosis in addition to residual mass size (primary tumour histology, prechemotherapy levels of the three tumour markers alphafetoprotein (AFP), human chorionic gonadotropin (HCG) and lactate dehydrogenase (LDH) and mass shrinkage during chemotherapy). This strategy resulted in improved true- and false-positive rates, even when categories of the predictors were simplified for practical application. We conclude that a simple statistical model, based on a limited number of patient characteristics, provides better guidelines for patient selection than those currently used in clinical practice.