Risk of perioperative hormonal breast cancer therapy for microvascular flap complications in breast reconstruction.

[BACKGROUND] Hormone therapy with selective estrogen modulators (tamoxifen) and aromatase inhibitors is commonly used in the treatment of breast cancer. While the increased risk for thromboembolic events has been known since their early application, the potential risk in microsurgical breast reconstruction is still debated. This study aimed to evaluate the risk for microvascular flap complications in patients with perioperative hormone therapy.

[METHODS] All patients who underwent microsurgical breast reconstruction with a deep inferior epigastric perforator (DIEP) or transverse myocutaneous gracilis flap at our institution between March 2010 and November 2020 were retrospectively identified in our records. Patients were grouped according to the type and use of perioperative hormone therapy. Flap-related thromboembolic events, flap loss, and revision procedures were compared and analyzed between groups. Risk factors associated with postoperative microsurgical complications were determined.

[RESULTS] A total of 560 patients (656 flaps) were included in our analysis. One hundred ninety-eight patients (224 flaps) received perioperative hormone therapy (35.4%) and 50 (8.9%) postoperative microsurgical events occurred. Tamoxifen and aromatase inhibitors were not associated with postoperative microsurgical events (p = 0.254), full flap loss (p = 0.702), or partial flap loss (p = 0.916). Patients receiving DIEP flaps had a higher risk for postoperative microsurgical complications (OR 2.36, p = 0.004) and partial flap loss (OR 14.66, p < 0.001). A BMI > 30 was associated with an increased risk for partial flap loss (OR 4.2; p < 0.001) CONCLUSION: This article presents one of the largest single-center datasets for the risks of hormone therapy in microsurgical breast reconstruction. Our results show that perioperative hormone therapy does not increase the risk for microsurgical complications. The findings of our study do challenge the common practice of discontinued hormone therapy before microsurgical breast reconstruction.