Abstract P4-11-02: Worse breast cancer prognosis in insulin treated diabetic patients - A population based registry study in Sweden

Abstract

Abstract Background. Diabetes may be linked to incidence of different tumor diseases and prognosis through various mechanisms such as the disease itself, hyperglycemia, obesity and anti-diabetes therapy. Material and methods. The study includes all women with BC diagnosed in Sweden between 2000 through 2008 (n=54406). The women had no previous cancer diagnosis during the period of 1958-1999. Dates of birth, BC diagnosis and TNM-stage where directly extracted from the cancer registry. The women’s anti-diabetes therapy was gathered from the Swedish Prescribed Drug Registry. Information regarding the cause of death and date of death was obtained from the Cause of Death Registry and tbe Swedish Population Register up until the 31st of December 2012 and 31st of December 2013 respectively. Analyses have been restricted to patients receiving insulin therapy (n=2463) and their breast cancer prognosis has been calculated in comparison with breast cancer patients without diabetes. All analyses were adjusted for TNM-stage and age at diagnosis. Results. Patients with insulin treated diabetes had a worse prognosis compared with other women with breast cancer (HR 1.7, 95%CI 1.5-2.0). The worse prognosis could be seen both for patients with ER+ and ER- tumors. The worst prognosis was seen for patients treated with NPH insulins (HR 2.8, 95% CI 2.4-3.3) while patients treated with long-acting insulin analogs had an intermediate prognosis (HR 1.6, 95% CI 1.2-2.2). Those women treated with NPH insulins and metformin had a slightly worse prognosis (HR 1.4, 95% CI 1.0-1.8). The results for breast cancer specific survival and total survival were similar. Conclusion. Our results imply that insulin treated breast cancer patients have a worse survival compared with other women with breast cancer regardless of tumor stage. Metformin therapy may partially counteract the association. Citation Format: Håkan Olsson, Rickard Einefors, Per Broberg, Mona Landin Olsson. Worse breast cancer prognosis in insulin treated diabetic patients - A population based registry study in Sweden [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-11-02.