(255) The Impact of Type 2 Diabetes on Complications After Primary Breast Cancer Surgery: A Danish Population-Based Cohort Study

Saturday, August 27, 2022

8:00 AM – 6:00 PM CEST

Location: Hall C

Publication Number: 929

Presenting Author(s)

Kasper Kj�rgaard
– Department of clinical epidemiology, Aarhus University & Aarhus University Hospital, Aarhus N, Midtjylland, Denmark

Co-Author(s)

Jannik Wheler
– Department of clinical epidemiology, Aarhus University & Aarhus University Hospital, Aarhus N, Midtjylland, Denmark
Looket Dihge
– Department of Plastic and Reconstructive Surgery, Department of Clinical Sciences, Surgery, Lund University, Skåne University Hospital, Sweden
Peer Christiansen
– Department of Plastic and Breast Surgery, Aarhus University Hospital, Denmark
Signe Borgquist
– Department of Oncology, Aarhus University Hospital, Aarhus, Denmark, Denmark
Deirdre Cronin-Fenton
– Department of Clinical Epidemiology, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark, Denmark

Background: Type 2 diabetes (T2D) is associated with obesity and other comorbidities involving multiple organ systems, which may increase the risk of postsurgical complications. Knowledge is sparse on the impact of T2D on the postsurgical outcome after breast cancer (BC) surgery in primary BC.

Objectives: To investigate the association of T2D and risk of complications after primary BC surgery, and according to neoadjuvant chemotherapy.

Methods: In May 2022, we gained access to the newest available data on a cohort of all Danish women diagnosed with early-stage operable BC during 1996-2018 registered in the Danish Breast Cancer Group clinical database. All patients had primary surgical treatment—mastectomy or breast conserving surgery. Information on prevalent T2D was collected from Danish medical and prescription registries, defining T2D via diagnostic codes or redemption of ≥2 prescriptions for glucose-lowering drugs. We defined postoperative complications as hospital admissions for medical or surgical complications (re-operations (excluding seromas), bleeding, infection, thrombosis, kidney or arterial cardiovascular disease) up to 30 days after primary BC surgery. We calculated the 30-day cumulative incidence function (CIF) of postoperative complications and used Cox regression to estimate hazard ratios (HR) and associated 95% confidence intervals (95% CI) overall, and stratified by the receipt of neoadjuvant chemotherapy, adjusting for potential confounders.

Results: Among 84,491 women with operable BC, 4,669 (5.5%) had prevalent T2D at time of BC surgery. Overall, 800 (17.1%) and 8,621 (10.8%) of BC patients with and without T2D developed postoperative complications corresponding to CIFs of 17% (95%CI: 16% - 18%) and 11% (95%CI: 10% - 11%), respectively, and a HR of 1.44 (95%CI: 1.34-1.56). 173 (3.7%) BC patients with T2D and 2,805 (3.5%) without T2D received neoadjuvant chemotherapy. Among those who did not receive neoadjuvant chemotherapy, the CIFs of postoperative complications was 17% (95% CI: 16% - 18%) and 11% (95% CI: 10% - 11%) for women with and without T2D, respectively, with a corresponding HR of 1.42 (95% CI: 1.31-1.53). For those with and without T2D who received neoadjuvant chemotherapy, the CIFs were 24% (95% CI: 18% - 30%) and 10% (95% CI: 9% - 11%), respectively, and with a corresponding HR of 2.08 (95% CI: 1.49-2.91).

Conclusions: Women with BC and prevalent T2D have higher risk of postoperative complications after primary BC surgery compared with BC patients without T2D, particularly those who receive neoadjuvant chemotherapy.