Diabetes self-care declined among patients undergoing adjuvant breast cancer treatment, alongside reduced monitoring, challenges in maintaining glycemic control, and increased emotional distress, according to a systematic review published in Diabetes & Metabolic Syndrome: Clinical Research & Reviews.
Across nine included studies, breast cancer treatment was frequently prioritized over diabetes management, contributing to reduced adherence to diet, physical activity, glucose monitoring, and medication use. Patients reported that treatment-related symptoms—including fatigue, nausea, and appetite loss—disrupted established diabetes routines and made consistent self-management more difficult.
Evidence from both qualitative and quantitative studies suggested challenges in maintaining diabetes control during treatment. In a cohort study of 11,878 patients with breast cancer, glycated hemoglobin testing declined more following cancer diagnosis compared with matched controls, with a 2% greater reduction over 24 months and a 5% greater decline within 6 months. In qualitative findings, 60% of patients reported that their glucose levels were out of control during treatment, and nearly half reported levels exceeding 200 mg/dL. Across studies, glycated hemoglobin values generally ranged from about 7% to 8%, consistent with suboptimal glycemic management.
Some patients also reported difficulty distinguishing symptoms related to cancer treatment from those related to diabetes, complicating day-to-day management.
Mental health burden was also a consistent finding. Cancer-related post-traumatic stress was associated with 6.6 times the odds of poorer perceived control over diabetes and 3.7 times the odds of greater emotional impact from the condition. Patients with both breast cancer and diabetes also experienced greater cancer-related fatigue before and throughout chemotherapy, with higher fatigue levels observed among those receiving anthracycline-based regimens.
The review highlighted persistent gaps in care coordination. Patients described uncertainty about which clinician was responsible for managing diabetes during cancer treatment, and oncology care often took precedence. Several studies reported reductions in diabetes monitoring and limited guidance on how to manage both conditions concurrently.
In one cross-sectional study, higher symptom burden was associated with poorer diabetes self-management and reduced physical function, underscoring the complexity of managing both conditions simultaneously.
One quasi-experimental study evaluated a potential intervention. A personalized diabetes care model with monthly virtual visits was associated with lower diabetes distress scores and higher treatment satisfaction over 3 months, suggesting a potential approach that warrants further study.
Researchers conducted the systematic review following Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, evaluating studies published from 2000 to 2025. Of 438 records identified, nine studies met inclusion criteria, including qualitative, cohort, cross-sectional, and quasi-experimental designs.
The evidence base was limited by variation in study design, sample size, and outcome measures. Most studies were conducted in the US, and several included small sample sizes. The quasi-experimental study did not include a control group, and cross-sectional findings did not allow causal relationships to be established.
“Diabetes self-care declined during breast cancer treatment, increasing the risk of poorer health outcomes, emotional distress and the progression of diabetes-related complications,” wrote lead study author Nicola Murfet of Deakin University in Australia, and colleagues.
Murfet was supported by a Deakin University PhD scholarship, and the researchers reported no competing interests.
Source: Diabetes & Metabolic Syndrome: Clinical Research & Reviews
