Patterns of relapse in extrapulmonary small cell carcinoma: retrospective analysis of outcomes from two cancer centres

Objectives: We conducted a retrospective review of patients with extrapulmonary small cell carcinomas (EPSCCs) to explore the distribution, treatments, patterns of relapse and outcomes by primary site. Setting: We have reviewed the outcomes of one of the largest data sets of consecutive patients with EPSCC identified from two major cancer centres. Participants: Consecutive patients with a histopathological diagnosis of EPSCC from the two institutions were retrospectively identified. Primary and secondary outcome measures: Outcomes were evaluated including stage at presentation, treatments given, sites of relapse, time to distant relapse, progression-free survival and overall survival (OS). Results: From a total 159 patients, 114 received first-line chemotherapy, 80.5% being platinum-based. Response rate was 48%. Commonest primary sites were genitourinary and gynaecological. 44% of patients presented with metastatic disease. 55.9% relapsed with liver the commonest site, whereas only 2.5% developed brain metastases. Median OS was 13.4 months for all patients, 7.6 months and 19.5 months for those with metastatic and non-metastatic disease, respectively. Gynaecological and head and neck patients had significantly better OS compared to gastrointestinal patients. Conclusions: EPSCCs demonstrate high response rates to chemotherapy and high rates of distant metastases. Primary sites may influence prognosis, and survival is optimal with a radical strategy. Brain metastases are rare and we therefore do not recommend prophylactic cranial irradiation.