Post-treatment Residual Clinicopathological Outcomes in Testicular Germ Cell Tumours.

Surgical resection is a generally accepted treatment for residual masses after chemotherapy for metastatic testicular germ cell tumour (GCT). About half the patients have necrosis in post-chemotherapy residual masses, whereas rest have viable tumour and teratoma. The likelihood of leaving behind teratoma with its subsequent complications such as growing teratoma syndrome necessitates resection outweighing its surgical complications. Ours is a retrospective observational study and aims at assessing post-chemotherapy residual masses in testicular GCTs and to predict importance of teratomatous and non-seminomatous components. A total of 62 cases of testicular GCTs resected after chemotherapy between January 2012 and June 2019 were included. Demographic, clinical, biochemical and imageological findings were noted and categorised according to WHO classification (2016). They were divided into two groups - those who underwent retroperitoneal lymph node dissection (RPLND) post-high inguinal orchidectomy (HIO) and chemotherapy (CT) as group 1 ( = 40) and those who underwent HIO and/or RPLND post-chemotherapy as group 2 ( = 22). The gross and microscopic examination was carried out to assess response to chemotherapy in terms of residual viable tumour, necrosis and teratoma. Viable tumour, necrosis and teratoma were 10%, 62.5% and 35% respectively in group 1 and in group 2, the same were 15%, 70% and 25% respectively in HIO specimen and 7%, 50% and 21% respectively in RPLND specimen. All the cases with viable tumour were proven to be yolk sac tumours (YST) based on morphology and immunohistochemistry (IHC).Twenty cases had teratoma in the post-CT residual masses out of which 11 cases had teratoma despite reduction in size. At a median follow-up of 47.85 months, 5 cases in group 1 and 2 cases in group 2 showed relapse and it was observed that group 1 had a prolonged relapse-free survival over group 2. Our study re-emphasises the importance of performing resection of residual mass post-CT irrespective of the size, imageological or biochemical evidence of tumour regression. There does not appear to be reliable predictors of post-chemotherapy histology of residual masses indicating the continued need for surgical resection in specialised centres.