Evaluation of body posture after unilateral mastectomy in patients with breast cancer: A retrospective single-center study

Objective: Every breast surgery carries a risk of complications. Patients with unilateral mastectomy tend to adopt a shoulder elevation posture on the opposite side to compensate for the weight loss caused by the mastectomy. The postural change resulting from this is considered one of these complications. This postural change can affect spinal alignment in the long term and lead to serious deformities that may cause scoliosis in the spine. The aim of this study is to evaluate the effect of unilateral mastectomy on postural changes and contribute to the literature. Materials and Methods: This is a retrospective study involving patients diagnosed with breast cancer between January 2, 2020, and September 30, 2024, at Ordu University Education and Research Hospital's General Surgery and Breast Clinic. Patients who underwent unilateral simple mastectomy and modified radical mastectomy due to histopathologically proven breast cancer, with preoperative and postoperative positron emission tomography (PET-CT) images, and a follow-up of at least 12 months after surgery, were included. The Cobb angles of the patients were measured before surgery and 12 months after surgery using vertebra images from the PET-CT scans. An angle value of 10° or greater was considered scoliosis. Results: A total of 29 patients who underwent unilateral mastectomy were examined in this study. Of these patients, 11 had a right-side mastectomy, and 18 had a left-side mastectomy. It was determined that 51.8% (n=15) of the patients had a right vertebral angle, 37.9% (n=11) had a left vertebral angle, and 10.3% (n=3) had a neutral angle. In 27.6% (n=8) of the patients, the curvature was ipsilateral, in 62.1% (n=18) it was contralateral, and in 10.3% (n=3) it was neutral. In 5 patients, the postoperative Cobb angle decreased compared to the preoperative Cobb angle, in 21 patients, the postoperative Cobb angle increased, and in 3 patients, the values remained the same. A statistically significant difference was found when comparing preoperative and postoperative Cobb angles (z=3.353, p=0.001). The average preoperative Cobb angle was 7.16±7.05, and the average postoperative Cobb angle was 9.03±6.23. A statistically significant difference was found between the curvature angle differences based on the side of the curvature (z=9.505, p=0.009). A larger curvature angle difference was found in patients with contralateral curvature. Conclusion: This study shows that the increase in the Cobb angle after unilateral mastectomy can lead to long-term changes in spinal alignment. Monitoring the Cobb angle and initiating physical rehabilitation early is important to prevent these changes.