Optimal timing of thoracic irradiation for limited stage small cell lung cancer: Current evidence and future prospects

Abstract

Lung cancer is a global health concern as the leading cause of cancer related mortality worldwide. Small cell lung cancer (SCLC) poses a formidable challenge to the treating physicians with the worst prognosis among all lung cancers. However, limited stage SCLC (LS-SCLC) has a relatively better outcome with multimodality management. Efforts have been focused on optimal integration of treatment modalities to achieve an improved therapeutic ratio for patients with LS-SCLC. While chemotherapy and thoracic radiation therapy (TRT) are primary components of initial management for LS-SCLC, there is no consensus on optimal timing of TRT. Within this context, we herein provide a concise overview of current evidence and future prospects regarding the optimal timing of thoracic irradiation for LS-SCLC in light of the literature.

Keywords: Small cell lung cancer; Thoracic irradiation; Limited stage small cell lung cancer; Timing of thoracic radiation therapy; Thoracic radiation therapy

Core Tip: There has been extensive effort to establish optimal timing of thoracic radiation therapy (TRT) in limited stage small cell lung cancer (LS-SCLC) management. While late TRT may have utility for management of LS-SCLC patients who may not tolerate curative-intent upfront chest irradiation due to excessive tumor burden at the outset, early TRT allows for exploiting the synergistic effect of chemoradiotherapy to eradicate as many tumor cells as possible in a shorter timeframe. Admittedly, differences in trial designs, definition of early and late TRT, patient selection criteria, administered chemotherapy regimens, treatment compliance, TRT dose and fractionation may affect treatment outcomes.