Purpose: To determine preoperative parameters that predict the histology of specimens obtained by retroperitoneal lymph node dissection (RPLND) in patients with nonseminomatous germ cell cancer (NSGCT) whose residual mass was </= 20 mm in diameter after modern cisplatin-based induction chemotherapy.
Patients and methods: Eighty-seven patients with metastatic NSGCT underwent RPLND after having received cisplatin- or carboplatin-based induction chemotherapy. In all patients, the largest diameter of the residual mass on the transaxial plane was </= 20 mm, as assessed by abdominal computed tomography (CT) immediately before RPLND.
Results: Complete fibrosis or necrosis was found in 58 patients (67%), teratoma was found in 23 patients (26%), and vital malignant germ cell tumor was found in six patients (7%), including one patient with rhabdomyosarcoma in the RPLND specimen. In five of the six latter patients, the residual lesion was </= 10 mm at pre-RPLND CT. No pre- or postchemotherapy clinical or radiologic parameter was identified that significantly predicted the histology of the residual mass.
Conclusion: One third of retroperitoneal postchemotherapy lesions </= 20 mm contained residual vital tumor tissue, despite modern chemotherapy regimens. Therefore, postchemotherapy RPLND remains necessary in patients with minimal-size residual lesions to facilitate easy and safe follow-up and initiate additional therapy as early as possible, thus avoiding recurrences.