Impact of pre-diagnostic triglycerides and HDL-cholesterol on breast cancer recurrence and survival by breast cancer subtypes

• Published in: BMC Cancer
• Main Authors: Trygve Lofterød, Elin S. Mortensen, Hawa Nalwoga, Tom Wilsgaard, Hanne Frydenberg, Terje Risberg, Anne Elise Eggen, Anne McTiernan, Sura Aziz, Erik A. Wist, Andreas Stensvold, Jon B. Reitan, Lars A. Akslen, Inger Thune
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2018
• Subjects: Breast cancer; Lipids; Molecular subtype; Triple negative breast cancer; Survival; Neoplasms. Tumors. Oncology. Including cancer and carcinogens; RC254-282; Tromsø
• Online Access: https://doi.org/10.1186/s12885-018-4568-2; https://doaj.org/article/76f1e9d55e5641e5a4e31b1716510d28

Abstract Background High triglycerides and low levels of high density lipoprotein (HDL)-cholesterol are observed to promote tumor growth. However, whether breast cancer heterogeneity may explain the contradictory influence of triglycerides and cholesterol observed on breast cancer prognosis remains unclear. Methods A population-based survival study among 464 breast cancer cases identified within the Tromsø study was conducted. Pre-diagnostic triglycerides, total-cholesterol and HDL-cholesterol were measured, and detailed clinical and histopathological data were obtained. Using tissue microarray, all breast cancer cases were reclassified into the following subtypes: Luminal A, Luminal B, HER2-enriched, and triple negative breast cancer (TNBC). Multivariable Cox proportional hazards regression models were used to study the associations between pre-diagnostic lipids and breast cancer recurrence, mortality, and survival. Results A total of 464 breast cancer patients, with mean age at diagnosis of 57.9 years, were followed for a mean 8.4 years. TNBC patients in the highest tertile of triglycerides (≥ 1.23 mmol/l) had 3 times higher overall mortality compared to TNBC patients in the lowest tertile (≤ 0.82 mmol/l) (HR 2.99, 95% CI 1.17–7.63), and the 5-year overall survival was 19% lower for TNBC patients in the highest vs. lowest tertile of triglycerides (65% vs. 84%). TNBC patients in the highest tertile of the HDL-cholesterol/total-cholesterol ratio (≥0.35), compared to those in the lowest tertile (≤0.27), had a 67% reduced overall mortality risk (HR 0.33, 95% CI 0.12–0.89). No associations were observed between lipids and prognostic outcome among breast cancer patients overall, or among patients with luminal A and luminal B subtypes. Among HER2-enriched patients, pre-diagnostic triglyceride level was inversely associated with overall mortality. Conclusion Our study suggests that pre-diagnostic triglycerides and the HDL-cholesterol/total-cholesterol ratio may independently provide unique information regarding ...