Cancer cachexia complicates advanced non-small cell lung cancer (NSCLC); however, it remains unclear how often cachexia occurs and how it affects the course of chemotherapy in patients receiving first-line systemic therapy. We conducted a multicentre, prospective observational study and enrolled previously untreated NSCLC patients with Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-2 and cachexia between September 2020 and September 2021.

The primary outcome measure was the trends in the Functional Assessment of Anorexia/Cachexia Treatment and Anorexia/Cachexia Subscale [FAACT (A/CS)] scores by cohort. Secondary outcome measures included the incidence of cachexia before the initiation of first-line systemic therapy, quality of life (QOL) measures, body weight (BW) changes, and efficacy and safety of first-line systemic therapy.

A total of 887 consecutive patients with previously untreated advanced NSCLC and ECOG PS of 0-2 who were initiated on first-line systemic therapy were evaluated. A total of 281 patients (31.7%) experienced BW loss consistent with the criteria of cachexia, and 186 were evaluated for QOL, BW and outcome measurements.

Overall, 180/186 patients received first-line systemic therapy. Cohort 1 (targeted therapy), cohort 2 [cytotoxic chemotherapy (CTx) ± immune checkpoint inhibitors (ICIs)] and cohort 3 (ICIs) included 42, 98 and 40 patients, respectively.

There were significant variations in QOL trends by cohort, with chemotherapy-associated emesis affecting early appetite-related QOL. The change in the FAACT (A/CS) score at 1 week from baseline was worse in cohort 2 (the least square mean change ± standard error: -3.0 ± 0.9) than in cohorts 1 (1.6 ± 1.2, p = 0.003) and 3 (1.8 ± 1.0, p = 0.002); meanwhile, the change at 6 weeks was worse in cohort 1 (-1.5 ± 1.2) than in cohorts 2 (3.6 ± 0.9, p = 0.001) and 3 (3.5 ± 1.1, p = 0.004).

BW reduction was observed in all cohorts within 6 weeks of therapy initiation. The targeted therapy cohort demonstrated superior progression-free survival (PFS) and overall survival (OS) to CTx ± ICIs cohort or ICIs cohort (median PFS was 9.7 months, 6.3 months, 3.1 months, in cohort 1, 2, 3, respectively (cohort 1 vs.

cohort 2: HR, 0.58, p = 0.018; cohort 1 vs. cohort 3: HR, 0.41, p = 0.001); median OS was not reached, 15.8 months, 9.9 months, respectively (cohort 1 vs.

cohort 2: HR, 0.52, p = 0.033; cohort 1 vs. cohort 3: HR, 0.37, p = 0.003).

Approximately 1/3 patients with previously untreated advanced NSCLC have cachexia. Appetite-related QOL trends vary based on the type of first-line systemic therapy in cachectic NSCLC patients, and the PFS and OS of these patients seemed to be shorter.