Impact of losing adipose tissue on outcomes from PD‐1/PD‐L1 inhibitor monotherapy in non‐small cell lung cancer

BACKGROUND: Adipose tissue induces inflammation, which desensitizes the efficacy of immunotherapy. However, several reports show that the therapeutic effect of programed cell death 1 (PD‐1)/programed death‐ligand 1 (PD‐L1) inhibitor(s) monotherapy is significantly better in obese patients. Therefore, the effect of adipose tissue on immunotherapy is unclear. METHODS: In this study, we retrospectively reviewed patients with advanced non‐small cell lung cancer (NSCLC) who received PD‐1/PD‐L1 inhibitor monotherapy between May 2016 and December 2018. We classified patients into total adipose tissue maintenance or loss groups according to adipose tissue change during the 6 months before treatment and compared the therapeutic effect of PD‐1/PD‐L1 inhibitors between these groups along with the presence or absence of cachexia, a poor prognostic factor. RESULTS: Of the 74 patients, 40 (54.1%) were cachexic. Among cachexic patients, we found no clear difference in the overall response rate (ORR) and progression‐free survival (PFS) between the total adipose tissue maintenance and loss group. However, among noncachexic patients, the total adipose tissue loss group had a higher ORR (64.7% vs. 23.5%, p < 0.05) and longer PFS (18.5 months vs. 2.86 months, p = 0.037) than the maintenance group. CONCLUSIONS: This study showed that decreasing adipose tissue without cachexia might favor the therapeutic effects of immunotherapy.