Predictors of residual mass histology following chemotherapy for metastatic non-seminomatous testicular cancer: a quantitative overview of 996 resections.

Following chemotherapy for metastatic non-seminomatous testicular cancer, surgical resection may demonstrate that residual masses contain purely benign tissue (necrosis), or potentially malignant tissues (histologically viable cancer cells or mature teratoma). The morbidity, mortality and costs of resection demand that resection is based on empirical data rather than on subjective judgements. We reviewed 996 resections from 19 studies to quantify predictors of the histology at resection. Predictors were analysed for each study and combined in a pooled odds ratio (OR). Predictors of necrosis were: (1) a teratoma-negative primary tumour (OR = 5.1); (2) normal tumour markers before chemotherapy [alpha-fetoprotein (AFP): OR = 2.8; human chorionic gonadotrophin (HCG): OR = 1.9; both AFP and HCG: OR = 5.7]; (3) a smaller postchemotherapy abdominal mass (e.g. < or = 20 mm: OR = 3.7); (4) a large shrinkage (> or = 90%: OR = 3.1); (5) lung resections versus abdominal resections (OR = 1.7). Cancer was found in only 4% of residual retroperitoneal masses < or = 20 mm. Further research may combine the primary tumour histology, marker level and mass size to improve clinical guidelines, which define subgroups of patients for whom the benefits of resection do not outweigh the risks.