No abstract

Background: Most of SCLC p are diagnosed with ED stage with a median overall survival (mOS) around 10 months (mo). However, nearly 3-5% of them show a survival > 24 mo. The aim of this study was to identify clinical factors related to LTS with ED-SCLC. Methods:We retrospectively included 161 p with ED-SCLC, treated between 2010-2018 at our institution. Clinical and pathological data were obtained from the electronic medical records. LTS was defined as survival 24 mo from the diagnosis. We compared categorical data between LTS and non-LTS-SCLC p using the Chi-square test. A survival analysis using the Kaplan-Meier method compared median progression free survival (mPFS) and mOS by log-rank test.Results: Median age was 65y, 81% were male and 96% former or current smokers. 90% had stage IV at diagnosis. Most common metastatic sites were liver (37%), bone (33%), adrenal (19%), lung (17%), and brain (13%). 61% had a PS 0-1 and 6% had a paraneoplastic syndrome. 89% of the p received first-line chemotherapy (52% cisplatin-based). Sixty-three p developed some grade 3-4 toxicity. 22% received prophylactic intracranial irradiation and 11% thoracic radiotherapy. Overall response rate (ORR) was 63%, with 7 complete responses and 95 partial responses. mOS and mPFS for the entire cohort was 8.5 and 8.3 mo, respectively. 23(16%) p fit the definition for LTS. mOS was 35 months (95% CI 28.4-41.5 vs 7.4 mo (95% CI 6.3-8.5) (p¼0.002) in the LTS and non-LTS cohorts, respectively. mPFS was 19.5 (95% CI 15.9-23.1) mo vs 7.3 (95% CI 6.3-8.3) mo (p¼0.002) in the LTS and non-LTS cohorts, respectively. A time to progression from the end of first-line treatment >6 mo (p¼0.02), rechallenge with platinum chemotherapy (p¼ 0.002) and immunohistochemical (IHC) positivity in tumor sample of Cam52 (p¼0.015), synaptophysin (p¼0.005) and CD56 (p¼0.015) have showed a significant association with LTS. Other clinical factors such as PS, brain and liver metastases, type of platinum, paraneoplastic syndrome, LDH levels, neutrophils/lymphocytes ratio did not differ between groups. Conclusions:We found interesting clinical associations with LTS phenotype. Nevertheless, molecular understanding will be crucial to elucidate the nature of LTS clinical difference behaviour.Legal entity responsible for the study: The authors.