Retrospective analysis on association of body mass index and immune checkpoint inhibitor response.

e14536 Background: The relationship between Body Mass Index (BMI) and cancer is a complex. We aim to study the impact of BMI on the response to immunotherapy in cancer patients. Methods: We did a retrospective observational study to investigate the influence of different BMI groups on patients receiving Immune Checkpoint Inhibitors (ICIs) at the University of Vermont Cancer Centre. We examined the medical records of people who received ICIs between January 2017 and June 2022 and collected demographic data, including age, sex, ethnicity, cancer stage, BMI, type and metastasis. We looked at Hazard Ratio (HR) in BMI subcategories compared to normal. The occurrence of immune-related adverse events (irAEs), metastasis and receipt of chemotherapy in different BMI subgroups was evaluated with relative risks (RRs). Results: A total of 288 cases were identified, out of which 269 had documented BMI, including 58% males, 94.8% whites with 64.17 years mean age. Lung cancer was most common at 41.3%, 46.5% were and 63.2% were stage 4. Total 71.4% of people received Pembrolizumab and 42.8% had concomitant chemotherapy. The median ECOG was 1 and the Charlson comorbidity index was 6. irAEs observed in 33% of cases, whereas mortality in 36%. The BMI distribution had 36.1% normal, 27.1% overweight, 16.5% obese, 14.5% extremely obese and 5.6% underweight. The HR in underweight subgroup was significant at 5.223 (p <0.001; 95CI: 2.2 to 12.4) compared to normal. The HR of overweight, obese and extremely obese decreased with HR of 1.15, 0.77 and 0.18 respectively but wasn’t significant as seen in Table 1. Table also shows that relative risk of irAEs, cancer stage, metastasis and concomitant chemotherapy were not significant. Conclusions: Clinically significant association was found between being underweight and mortality in cancer patients receiving immunotherapy. Table: see text