Effect of Adjuvant Treatments on Recipient Vessel Diameter for Free Flap Breast Reconstruction Using Computed Tomographic Angiography Analysis.

: The quality of recipient vessels is critical for successful microsurgical breast reconstruction, and iatrogenic damage should be minimized. Adjuvant radiotherapy (RTx) and chemotherapy (CTx) are widely used for breast cancer and may induce structural changes in recipient vessels. This study aimed to evaluate changes in recipient vessel diameters for breast reconstruction after adjuvant treatment in patients with breast cancer. : A total of 167 patients with unilateral breast cancer who underwent surgical resection between 2017 and 2021 were retrospectively reviewed. Patients were classified into four groups: mastectomy only without adjuvant treatment (group A, = 33), adjuvant RTx only (group B, = 44), adjuvant CTx only (group C, = 43), and combined adjuvant CTx and RTx (group D, = 47). Preoperative and postoperative computed tomography angiography was used to measure the diameters of the thoracodorsal artery (TDA) and internal mammary artery (IMA) on the affected and unaffected sides. Differences in vessel diameters between sides and among groups were analyzed. : In groups B and D, the diameters of the affected TDA and IMA were significantly decreased compared with the changes observed on the unaffected side ( < 0.001). In contrast, there were no significant differences in vessel diameters between the affected and unaffected sides in groups A and C (group A: = 0.644; group C: = 0.367). : Recipient vessel diameters for microsurgical breast reconstruction significantly decreased in patients who received postoperative RTx, with or without CTx. Plastic surgeons planning delayed breast reconstruction should be aware of these adjuvant therapy-related changes in recipient vessels and consider preoperative imaging assessment to accurately counsel patients regarding surgical risks and to support informed decision-making.