Detection of retroperitoneal metastases in early-stage nonseminomatous testicular cancer: analysis of different CT criteria.

To determine the predictive values of using different sizes on CT as criteria for the detection of retroperitoneal lymph-node metastases in patients with early-stage (nodes 5 cm or less in diameter) primary nonseminomatous testicular cancer, we performed a retrospective analysis of 51 patients. Measurements of lymph-node transaxial diameters on CT were correlated with histologic findings at lymph-node dissection or with response to initial chemotherapy. All patients had normal serum markers (alpha-fetoprotein, human chorionic gonadotropin) after orchiectomy. The frequency of lymph-node metastases in this population was 51%. When a CT criterion of 5 mm was used, the negative predictive value was 79%; the positive predictive value, 62%; the specificity, 44%; and the sensitivity, 88%. With a criterion of 15 mm, the negative predictive value was 63%; the positive predictive value, 71%; the specificity, 76%; and the sensitivity, 58%. Metastases in retroperitoneal lymph nodes that appeared within normal limits (i.e., had normal transaxial diameters) on CT were the limiting factor in the ability of CT to exclude the presence of metastases. We conclude that using smaller sizes on CT scans as the criteria for detection of lymph-node metastases cannot replace dissection of nodes in patients who have normal-sized nodes but may be helpful in identifying a subgroup of patients who are at lower risk of harboring metastases when treatment by orchiectomy alone is considered.