Abstract P4-07-06: Circulating lipids and breast cancer survival in the Malmö diet and cancer study

Abstract

Abstract Rationale: Overweight and obesity are associated with inferior prognosis in breast cancer. The explanation is considered multifactorial, and dyslipidemia may be a contributing factor. The purpose of this study was to examine the association between circulating lipids and breast cancer outcomes in patients enrolled in the Malmö Diet and Cancer Study (MDCS). Patients and methods: Circulating lipid levels were measured in the blood sampled upon enrollment in the female MDCS cohort (N=17,035). We identified all MDCS participants with incident invasive breast cancer diagnosed between 1991-2014. The follow-up time began at breast cancer diagnosis and continued until the first event of breast cancer recurrence, death, emigration, or five years of follow-up. We estimated the incidence rates of recurrence at five years and fit Cox regression models to compute crude and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CI) of breast cancer recurrence as well as all-cause mortality according to cohort-specific tertiles of apolipoprotein A-1 (Apo A-1) and apolipoprotein B (Apo B). Results: We enrolled 850 eligible patients. During the five years of follow up, 90 invasive recurrences with over 3,807 person-years occurred. In multivariable analyses, high levels of Apo B were associated with an increased rate of recurrence (tertile 3 vs. 1, HR= 2.30 [95% CI: 1.13-4.68]). However, high levels of Apo B were not associated with all-cause mortality (tertile 3 vs. 1, HR= 1.23 [95%CI: 0.68-2.25]). We observed no associations between levels of Apo A-1 and recurrence (tertile 3 vs. 1, HR= 1.34 [95%CI: 0.70-2.58]) or all-cause mortality (tertile 3 vs. 1, HR=1.12 [95%CI: 0.61-2.05]). Conclusion: High pre-diagnostic levels of Apo B were associated with an increased risk of recurrence among breast cancer patients. Circulating Apo A-1 was not associated with breast cancer outcome. These results warrant further investigation into the importance of lipid-regulation in breast cancer patients. Citation Format: Sixten Harborg, Thomas P Ahern, Maria Feldt, Ann H Rosendahl, Deirdre Cronin-Fenton, Olle Melander, Signe Borgquist. Circulating lipids and breast cancer survival in the Malmö diet and cancer study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-07-06.