Nodule Size After Chemotherapy and Primary-Tumor Teratoma Components Predict Malignancy of Residual Pulmonary Nodules in Metastatic Nonseminomatous Germ Cell Tumor.

BACKGROUND: The treatment goal for visceral metastatic nonseminomatous germ cell tumor (NSGCT) is to remove any residual teratoma or viable NSGCT after chemotherapy. However, this provides no therapeutic benefit to patients whose metastases necrotize on their own. This study therefore analyzed NSGCTs with pulmonary metastases to determine preoperative factors that predict necrosis and could help identify patients who might be treated with monitoring rather than surgery.

METHODS: The study retrospectively analyzed 41 patients (135 metastatic pulmonary nodules) treated from 1997 to 2016 for NSGCT who showed tumor marker normalization after chemotherapy. Relationships between clinicopathologic characteristics and necrosis in resected pulmonary specimens were analyzed.

RESULTS: Receiver operating characteristic analysis of the pulmonary nodules showed 9 mm to be the optimal cutoff length for predicting necrosis. The logistic regression model showed that absence of teratoma components in the primary tumor and all pulmonary nodules shorter than 10 mm after chemotherapy both were independent predictors of pathologic necrosis in pulmonary specimens. No patients experienced late recurrence (i.e., > 2 years afterward).

CONCLUSIONS: The presence of teratoma components in primary tumors and nodular size after chemotherapy predict the pathology of residual pulmonary nodules. Patients whose residual nodules all are shorter than 10 mm and who have no primary-tumor teratoma components might be candidates for careful monitoring before pulmonary resection.