ED14.01 Chemotherapy of Small Cell Lung Cancer

Abstract

Small cell lung cancer, which accounts for 10-15% of all lung cancers, is a biologically and clinically virulent malignancy that has a propensity to disseminate systemically and therefore is often initially diagnosed at an advanced incurable stage. Although typically associated with heavy tobacco use, there have been recent clinical observations of histologic evolution from adenocarcinoma to a SCLC phenotype, particularly in tumors harboring activating mutations in the epidermal growth factor receptor (EGFR) gene that had been treated with EGFR inhibitors. Due to its high proliferative rate, SCLC is known to be highly responsive – at least initially - to cytotoxic chemotherapy. Tumor response rates of 50-70% following platinum-based chemotherapy are usually expected. Intracranial metastases, a common feature of ES-SCLC, have been also shown to respond at a similar rate to cytotoxic therapy as that of metastases to other visceral organs. The standard frontline chemotherapy for ES-SCLC, unchanged for the past three decades, has been platinum (either cisplatin or carboplatin) plus etoposide. No other regimen has convincingly been demonstrated to be superior to platinum-etoposide in the frontline setting. Neither dose intensification approaches nor the incorporation of other cytotoxic agents into the platinum backbone have yielded any palpable or tangible survival benefits. In recent years, only prophylactic cranial irradiation and (in highly selected patients) consolidative thoracic irradiation have been shown to marginally improve survival outcomes. Furthermore, despite the high initial response rates to chemotherapy, drug resistance and subsequent tumor progression are universal events. Following failure of frontline platinum-based therapy, therapeutic options are limited and generally are of very modest clinical benefit. Current investigations into optimizing cytotoxic therapy include the development of novel cytotoxics (e.g., alisertib), sequential/combination strategies that involve novel “targeted” therapies and immunotherapeutics such as checkpoint inhibitors, or conjugating a cytotoxic payload onto a monoclonal antibody directed against an antigen expressed on SCLC, among others. A critical appraisal of the current status and future directions of cytotoxic therapy in ES-SCLC will be presented. sclc, small cell, neuroendodrine