A comparison of the outcomes of pulmonary versus extrapulmonary extensive-stage small cell carcinoma.

BACKGROUND: Extrapulmonary small cell carcinomas (EPSCCs) are rare cancers, comprising 0.1-0.4% of all cancers. The scarcity of EPSCC studies has led current treatment strategies to be extrapolated from small cell lung cancer (SCLC), justified by analogous histological and clinical features. AIMS: We conducted a retrospective cohort study comparing the outcomes of extensive-stage (ES) SCLC and EPSCC. METHODS: Patients diagnosed with ES SCLC or EPSCC between 2010 and 2020 from four hospitals in Sydney were identified. Patients who received active treatment and best supportive care were included. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS) and overall response rates (ORRs). RESULTS: Three hundred and eighty-four patients were included (43 EPSCC vs. 340 SCLC). EPSCC were of genitourinary (n = 15), unknown primary (n = 13) and gastrointestinal (n = 12) origin. Treatment modalities for EPSCC compared to SCLC included palliative chemotherapy (56% vs 73%), palliative radiotherapy (47% vs 59%) and consolidation chest radiotherapy (10% of SCLC). Overall, median OS was 6.4 versus 7 months for EPSCC versus SCLC respectively, but highest in prostate EPSCC (25.6 months). Of those who received chemotherapy (22 EPSCC vs 233 SCLC), median OS was 10.4 versus 8.4 months (HR OS 0.81, 95% confidence interval (CI): 0.5-1.31, P = 0.38); PFS was 5.4 versus 5.5 months (HR PFS 0.93, 95% CI: 0.58-1.46, P = 0.74) and ORR were 73% versus 68%. CONCLUSIONS: EPSCC and SCLC appeared to have comparable OS and treatment outcomes. However, the wide range of OS in EPSCC highlights the need for an improved understanding of its genomics to explore alternative therapeutics.

Outcomes of extensive stage extrapulmonary small cell cancer.

BACKGROUND: Extrapulmonary small cell cancer (EPSCC) is a rare malignancy with an incidence of approximately 0.1%-0.4% of all cancers. Treatment of this disease is often based on small cell lung cancer. AIMS: We aimed to investigate real-world clinical outcomes of patients with extensive-stage (ES) ESPCC. METHODS: Patients diagnosed with ES EPSCC between 2010 and 2020 from multiple centres in New South Wales were identified. Patient, disease and treatment characteristics were collected and presented using descriptive statistics. Survival was analysed using the Kaplan-Meier method. Univariate and multivariate Cox regression hazard models were used to identify potential prognostic factors. RESULTS: Sixty eligible ES EPSCC patients were identified, including 65% male and 35% female. The mean age was 69 years (range 37-88). Forty-five per cent were never smokers, 42% ex-smokers and 13% current smokers, and 17% of patients had limited-stage disease prior to development of ES disease. The most common primary sites were genitourinary (42%; mainly prostate (n = 14) and bladder (n = 10)), gastrointestinal (28%; mainly oesophagus (n = 5) and colon (n = 4)) and unknown primary (22%). Treatments received included palliative chemotherapy (67%), palliative radiotherapy (53%), palliative surgery (13%) and best supportive care alone (13%). The median overall survival (OS) was 8.0 months. The median progression-free survival was 5.4 months, and response rate to first-line chemotherapy was 65%. Platinum-based chemotherapy was prognostic of longer OS (HR 0.27, CI 0.12-0.60, P = 0.001). CONCLUSIONS: Patients with ES EPSCC had good response to palliative chemotherapy, but OS remained poor. Further research is required to improve the prognosis in this population.