The prognostic impact of obesity on breast cancer patients according to molecular subtype

Objective To analyze the effect of obesity on the risk of breast cancer death in patients with different molecular subtypes.Methods The information of breast cancer patients who were first diagnosed between 2016 and 2017 from Liaoning province were collected retrospectively. A total of 2340 primary and invasive female breast cancer patients were included in the analysis and followed up until June 30, 2023. A Cox proportional risk model was used to analyze the risk of breast cancer death of obesity in different molecular subtypes.Results Among 2340 breast cancer patients, 343 were obese women, accounting for 14.7% of all the patients. Obese patients had a higher proportion of Luminal A and triple-negative breast cancer compared to non-obese patients(p=0.005).170 patients death from breast cancer(7.3%). Obese women had a higher risk of breast cancer death compared to non-obese women, with an HR of 1.629 (95%CI 1.118-2.375). Compared with Luminal A, patients with Luminal B, HER2 overexpression, and triple-negative breast cancer had a higher risk of death, HR was 1.917 (95%CI 1.235-2.974), 2.116 (95%CI 1.370-3.267) and 2.112 (95%CI 1.337-3.336), respectively. After adjusting for confounders, obesity was associated with an increased risk of breast cancer death in Luminal A patients, HR was 2.255 (95%CI 1.338-3.802).Conclusions Obesity is an independent risk factor for the prognosis of LuminalA breast cancer patients, but no significant effect are observed on the other molecular subtypes of breast cancer.