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.