Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a highly malignant tumor with rapid proliferation rate. It has a high propensity for nodal metastases and to bone, liver, and brain. Majority present in advanced or metastatic stage at presentation. It has been classified into limited or extensive stage in routine clinical practice depending on whether the disease can be encompassed into a safe radiation portal. TNM staging can also prognosticate between different stages of disease and is recommended for clinical use. SCLC is highly sensitive to both chemotherapy and radiation therapy. Surgery has a very limited role to play because of high nodal metastases. Platinum-based regimen like cisplatin and etoposide is the regimen of choice for chemotherapeutic management of SCLC. Chemotherapy for four to six cycles along with early concurrent radiation therapy is the standard treatment for SCLC with no visceral metastases and results in 5-year overall survival (OS) rate of 20–25%. Prophylactic cranial irradiation (PCI) reduces the risk of intracranial metastases and improves OS. In metastatic disease or disease not feasible for concurrent radiation, four to six cycles of carboplatin and etoposide is the preferred chemotherapy regimen. Consolidative radiation to chest reduces the risk of symptomatic intrathoracic recurrences but does not provide a significant OS advantage. PCI is recommended after any response to initial chemotherapy; however, its use is debated as OS benefit has not been shown in extensive disease. SCLC is notorious for relapse in majority of patients and often does not respond to second-line therapy. Immune checkpoint inhibitors have recently showed improvement in OS and is the most significant advancement in the last three decades, in the management of SCLC.