Worse breast cancer prognosis in insulin treated diabetic patients - A population based registry study in Sweden

• 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.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

Nyckelord

insulin

insulin derivative

metformin

isophane insulin

long acting insulin

breast cancer

cancer prognosis

human

register

diabetic patient

population

Sweden

prognosis

female

diabetes mellitus

patient

therapy

neoplasm

cancer staging

cancer patient

survival

cause of death

diagnosis

obesity

cancer specific survival

hyperglycemia

insulin treatment

death

cancer registry

cancer diagnosis

diseases

Publikations- och innehållstyp

kon (ämneskategori)

ref (ämneskategori)