Comparison between concurrent and sequential chemoradiation for non-small cell lung cancer in vitro

Current practice guidelines recommend the combination of chemotherapy and thoracic radiation for locally advanced non-small cell lung cancer (NSCLC). Previous meta-analyses have shown that concurrent chemoradiation (CCRT) may be superior to sequential chemoradiation (SCRT). However, few previous in vitro studies have analyzed these two treatment schedules. In the current study, four lung cancer cell lines harboring wild-type epidermal growth factor receptor, comprising two squamous and two non-squamous cell lines, were used. The IC₁₀ concentrations of three platinum-based regimens were combined with radiation treatment. Cells were irradiated at 0, 2, 4, 6 and 8 Gy using a ¹³⁷Cs irradiator concurrently or sequentially. Surviving fractions (SFs) were plotted as a function of the radiation dose. In A549 cells, only the docetaxel (Doc) and carboplatin (Carbo) combination showed a significant radiosensitizing effect with CCRT treatment. For the other three cell lines, no difference was identified in the SFs between CCRT and SCRT. An in vitro method of comparing CCRT with SCRT was established using lung cancer cell lines. Overall, no significant difference was detected in the radiosensitizing effect of the two treatment schedules, with the exception of the A549 cell lines treated with Doc/Carbo.