Pre-Existing Diabetes in Early Stage Breast Cancer Patients is Associated with Lack of Improvement in Quality of Life 2 Years After Diagnosis

Purpose: Type 2 diabetes is a common comorbidity among breast cancer survivors. Our aim was to assess the association between diabetes and quality of life (QOL) in newly diagnosed early stage (0-IIA) breast cancer patients over a 2-year follow-up. Methods: We used data from a longitudinal study of 549 breast cancer patients, aged ≥40 years. During four telephone interviews administered 4–6 weeks and 6, 12, and 24 months after definitive surgical treatment, we measured QOL using the Functional Assessment of Cancer Therapy-Breast (FACT-B) scale; higher scores indicate better QOL. Repeated measures analysis of variance was used to test the change over time in total FACT-B and each of the five subscales (physical, social, emotional and functional well-being, and breast cancer concerns), comparing patients with and without diabetes at baseline. Results: After adjusting for covariates (age, race, body mass index, education, marital status, cancer staging, and surgical side effects), patients with (vs. without) diabetes reported lower QOL over time on the total FACT-B (least-squares mean [standard error] 106.2 [2.1] vs. 112.0 [1.1]; p = 0.0038) and on physical, social, emotional, and functional well-being subscales (each p < 0.05). Over the 2-year follow-up, QOL improved significantly for the emotional well-being (p < 0.0001) and breast cancer concern subscales (p = 0.0282) among patients without diabetes, but not among patients with diabetes. Conclusion: Early stage breast cancer patients with diabetes may need additional care considerations to improve QOL.