Advanced germ cell tumor patients undergoing post-chemotherapy retroperitoneal lymph node dissection: Impact of residual teratoma on prognosis.

OBJECTIVES

To evaluate the histologic findings and clinical outcomes of post-chemotherapy retroperitoneal lymph node dissection for advanced germ cell tumor.

METHODS

We analyzed the medical records of 66 patients who underwent post-chemotherapy retroperitoneal lymph node dissection between 2005 and 2019 at Tsukuba University Hospital.

RESULTS

The proportions of necrosis, teratoma, and viable germ cell tumor in the specimens were 62.1%, 36.4%, and 1.5%, respectively. The 5-year progression-free and overall survival rates were 82.3% and 91.3%, respectively. The 5-year overall survival rate of patients with residual teratoma was significantly worse than that of patients with necrosis only (74.1% vs 100%). Overall, three patients died: one from cancer and two from teratoma with somatic-type malignancy. Of these, two patients relapsed after incomplete resection of residual teratoma. When limited to patients with completely resected teratoma, the 5-year overall survival rate was 91.7%, which did not differ from that for patients with necrosis only. Multivariate analysis showed that presence of teratoma in the primary site and decrease in retroperitoneal lymph node mass to less than 50% of the initial tumor size were independent factors for residual teratoma. However, the absence of these factors could not reliably predict necrosis only in retroperitoneal lymph node dissection specimens.

CONCLUSIONS

In our series, 98% of post-chemotherapy retroperitoneal lymph node dissection pathology was either necrosis or teratoma, with viable germ cell tumor only found in 2% of patients. Residual teratoma was associated with poorer prognosis, especially in cases of incomplete resection.