Extrapulmonary small cell carcinoma: Prognostic factors, patterns of care, and overall survival

Abstract

Background: Extrapulmonary small cell carcinoma is a rare malignancy with scarce data. Treatment paradigms extrapolate from pulmonary small cell carcinoma and single institution studies. We analyzed the epidemiology, patterns of care, prognostic factors, and overall survival (OS) of EPSCC patients.

Methods: The cohort included EPSCC. Patients with <2 months follow-up, unknown demographic/treatment variables were excluded. Descriptive statistics were performed to characterize the cohort. Kaplan-Meier methods were used to estimate OS. Cox proportional hazard modeling was done to analyze the influence of prognostic variables on OS.

Results: 5747 patients were included. Median OS was 1.2 years. Head and neck (HR: 0.60, 95% CI 0.53-0.67, p < 0.0001) and breast (HR: 0.69, 95% CI 0.53-0.89, p = .0046) were associated with improved OS; gastrointestinal (HR: 1.19, 95% CI 1.09-1.29, p < .0001) worse OS; and gynecologic (HR: 1.04, 95% CI 0.92-1.17, p = .5660) showing no difference, all compared to genitourinary (reference). Surgery was associated with improved overall survival (HR: 0.84, 95% CI 0.79-0.91, p=<.0001). Chemoradiation showed a decreased HR (HR: 0.91, 95% CI 0.83-0.99, p = .0363) when compared to chemotherapy alone (reference).

Conclusion: EPSCC occurs throughout the body with poor survival. Anatomic subsite was predictive for survival. Surgical resection may improve survival. Concurrent chemoradiation appears to improve survival over chemotherapy alone.

Keywords: Chemotherapy; Extrapulmonary small cell; Overall survival; Radiation; Surgery; Treatment paradigms.