Rapid Fire Best of the Best Poster Oral Clinical Oncology Society of Australia Annual Scientific Meeting 2021

Outcomes of Extensive-Stage Extrapulmonary Small Cell Cancer (#227)

Geovanny Gandy 1 , Po Yee Yip 1 2 , Annette Tognela 1 2 , Peey Sei Kok 1 3
  1. Western Sydney University, Campbelltown, New South Wales, Australia
  2. Macarthur Cancer Therapy Centre, Campbelltown Hospital, Campbelltown, New South Wales, Australia
  3. National Health and Medical Research Council Clinical Trials Centre, The University of Sydney, Camperdown, New South Wales, Australia

Aims: Extrapulmonary small cell cancer (EPSCC) is a rare malignancy with incidence approximately 0.1% – 0.4% of all cancers1. Treatment of this disease is often based on small cell lung cancer. We aimed to investigate real-world clinical outcomes of patients with extensive stage (ES) ESPCC.

Methods: Patients diagnosed with ES-EPSCC in 2010-2020 from South West Sydney Local Health District 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: Forty-four eligible ES-EPSCC patients were identified, including 64% male and 36% female. The mean age was 69 years old (range 37-88). There were 50% non-smokers, 43% ex-smokers and 7% current smokers. 14% of patients had limited-stage disease prior to development of ES disease. The most common primary sites were genitourinary (39%; mainly bladder [n=9] and prostate [n=8]), gastrointestinal (27%; mainly colon [n=5] and oesophagus [n=4]) and unknown primary (27%). Treatments received included palliative chemotherapy (59%), palliative radiotherapy (48%), palliative surgery (11%) and best supportive care alone (14%). The median overall survival (OS) was 7.0 months.  The median progression-free survival (PFS) was 5.4 months and response rate to first-line chemotherapy was 67%. Platinum-based chemotherapy was a positive prognostic factor for OS in both univariate (hazard ratio [HR] 0.25; 95% confidence interval [CI] 0.12-0.54; P < 0.001) and multivariate analyses (HR 0.28, CI 0.10-0.73, P = 0.01).

Conclusion: Patients with extensive stage EPSCC had good response to palliative chemotherapy but associated with poor overall survival, which is likely due to development of drug resistance. Further research is required to improve prognosis in this population.

  1. Brennan SM, Gregory DL, Stillie A, Herschtal A, Mac Manus M, Ball DL. Should extrapulmonary small cell cancer be managed like small cell lung cancer? Cancer. 2010;116(4):888-95.