Efficacy and safety of reduced‐dose chemotherapy plus immunotherapy in patients with lung squamous cell carcinoma: A real‐world observational study

Recently, chemotherapy plus immunotherapy has achieved remarkable efficacy in lung squamous cell carcinoma (LUSC). However, some patients, especially frail people, cannot tolerate full-dose chemotherapy in the real world. To reduce toxicity, appropriate dose reduction in chemotherapy is necessary. Therefore, this study aimed to demonstrate the efficacy and safety of reduced-dose chemotherapy plus immunotherapy in LUSC patients in the real world.A real-world observational study was conducted concerning patients who received chemotherapy plus immunotherapy in our situation. The primary endpoints were objective response rate (ORR) and disease control rate (DCR), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicity.Between December 2018 and January 2022, 110 patients were enrolled, of whom 54 patients were chemotherapy reduced-dose group and 56 patients were chemotherapy standard-dose group. The ORR in the reduced-dose group is similar to standard-dose group (85.19% vs. 71.43%, p = 0.082). Similar DCR were observed (100% vs. 94.64%, p = 0.086). Median PFS was 12 months in the reduced-dose group and standard-dose group, respectively. Median OS was 15 months and 16 months in the reduced-dose group and standard-dose group, respectively. We reported a lower incidence of grade 3-4 toxicity in the reduced-dose group compared with standard-dose group (27.78% vs. 42.86%, p = 0.100). The major toxic reactions were better alleviated in the reduced-dose group than in the standard-dose group, especially in the thrombocytopenia (p = 0.044), peripheral nerve damage (p = 0.001), gastrointestinal reactions (p < 0.0001), and fatigue (p = 0.001).The modified regimen with attenuated doses of chemotherapy in combination with immunotherapy was effective and well tolerated in patients with LUSC. The efficacy of this modified regimen is similar to that of the full-dose regimen.