Abstract 2206: Obesity and cancer outcomes among patients with lung cancer and cutaneous melanoma treated with immune checkpoint inhibitors and EGFR inhibitors

Abstract Background: Obesity is a causal factor in cancer risk and progression. Immune checkpoint inhibitors (ICI) and EGFR inhibitors (EGFRi) are indicated for the treatment of several cancers, including non-small-cell lung cancer (NSCLC) and cutaneous melanoma (CM). Improved outcomes was observed with ICI in preclinical studies. We aimed to determine the association of obesity with progression-free survival (PFS) or overall survival (OS) among patients with NSCLC and CM treated with ICI or EGFRi. Methods: This was a retrospective study utilizing 2011-2019 SEER-Medicare data of Medicare Parts A and B enrolled patients ≥66 years diagnosed with NSCLC or CM who received ICI or EGFRi (NSCLC only) within 1-year post-diagnosis. Patients were followed from treatment commencement until death, loss to follow-up, or end of study. Descriptive statistics and survival analysis were used to achieve study objectives. Results: Among 2393 NSCLC patients receiving ICI, obese patients (N=281, 11. 7%) were younger (73. 4±5. 2 yrs vs 74. 4±5. 9 yrs, p0. 01) with higher CCI scores (2 (IQR=1-4) vs 1 (IQR=0-2), p0. 0001) compared to non-obese patients (N=2, 311, 89. 2%). Time to progression (TTP) was 41% faster among obese patients (392 days (95% CI=330-468) vs 493 days (95% CI=464-525), p0. 01; HR=1. 41 (1. 13-1. 76), p0. 01) with no significant difference in time to death (TTD) (443 days (404-488) vs 491 days (462-524), p=0. 35). Among 880 CM patients, those with obesity (N=91, 10. 3%) ) were significantly younger (74. 7±6. 1 yrs vs 76. 3±7. 3 yrs, p=0. 02) with higher CCI scores (2 (IQR=0-4) vs 0 (IQR=0-2), p0. 0001). TTP was 343 days (320-400). TTD was 1, 409 days (1, 107-2, 136) with no association between obesity status and PFS or OS. Among 2, 524 NSCLC patients receiving EGFRi, obese patients (126, 5. 0%) were younger (73. 7±6. 1 yrs) vs 75. 6±6. 5 yrs, p0. 01), had higher CCI scores (2 (IQR=1-3) vs 0 (IQR=0-1), p0. 0001), and longer time to treatment (3 mths (IQR=1-7) vs 2 mths (IQR=1-6), p=0. 02). A higher proportion were White (76. 2% vs 61. 3%, p0. 001). Risk of progression was 48% higher among obese patients (664 dys (496-778) vs 1, 231 dys (1, 127-1, 379), p0. 0001; HR=1. 48, 95% CI=1. 11-1. 97, p0. 01) with no significant difference in TTD (559 dys (440-763) vs 673 dys (639-707), p=0. 35). Conclusion: Obesity with associated with PFS but not OS among patients with NSCLC with no association observed among patients with CM. Given that the link between obesity and NSCLC risk remains controversial, the observed association with PFS may be linked to the absence of the paradoxical effect of improve outcomes that may be seen with cancers caused by obesity such as CM. Citation Format: Sabina O. Nduaguba, Lori Hazlehurst. Obesity and cancer outcomes among patients with lung cancer and cutaneous melanoma treated with immune checkpoint inhibitors and EGFR inhibitors abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 2206.