ObjectiveTo explore the application and effectiveness of three-pedicle reduction mammoplasty in breast cancer patients with moderate or greater breast hypertrophy and/or moderate-to-severe breast ptosis. Methods The clinical data of 15 breast cancer female patients with hypertrophy and/or moderate-to-severe breast ptosis treated by three-pedicle reduction mammaplasty with inverted T incision between January 2019 and March 2021 were retrospectively analysed. The patients were aged 31-58 years, with a median age of 39 years. The disease duration ranged from 10 days to 9 months (median, 3.4 months). All patients had unifocal tumor, with a maximum diameter of primary tumor of 0.5-3.9 cm (mean, 2.0 cm), of which 12 were diagnosed with invasive carcinoma and 3 carcinoma in situ. Tumor stage: TisN0M0 in 3 cases, T1N0M0 in 4 cases, T1N2M0 in 2 cases, T2N0M0 in 4 cases, and T2N1M0 in 2 cases. The preoperative cup sizes of patients were D cup in 3 cases, DD cup in 1 case, E cup in 2 cases, EE cup in 2 cases, F cup in 2 cases, FF cup in 1 case, and ≥G cup in 4 cases. The distance from nipple to inframammary fold was 8-18 cm (mean, 12.2 cm) before operation. The patients were followed up regularly after operation to evaluate the breast reduction effect and complications; Breast cancer reporting outcome scale (BREAST-Q) was used to assess patients’ satisfaction and quality of life; and ultrasound, chest and abdominal CT, whole-body bone scan were performed to assess local tumor recurrence or distant metastasis. Results The postoperative nipple position was slightly higher than inframammary fold in all patients. Postoperative cup sizes were A cup in 3 cases, B cup in 6, C cup in 4, D cup in 1, and DD cup in 1, which showing significant difference when compared with preoperative cup sizes (Z=3.420, P=0.001). The median follow-up time was 9 months (range, 6-33 months). Postoperatively, 2 cases (13.3%) had wound-site cellulitis, 1 (6.7%) had mild fat liquefaction, 2 (13.3%) had nipple and areola hypoesthesia but recovered after 3 months. No complication such as fat necrosis, papillary areola complex, or flap necrosis occurred. All patients had undergone adjuvant radiotherapy, of which 1 (6.7%) showed mild skin color change after radiotherapy, but no radiotherapy-related complication occurred in all patients. No patient was readmitted, received reoperation, or delayed to adjuvant therapy due to complications. In the BREAST-Q score, breast satisfaction and quality of life scores at 3 and 6 months after operation were significantly better than those before operation and at 1 month after operation (P<0.05); no significant difference was found between at 1 month after operation and before operation (P>0.05). Nipple satisfaction scores at 1, 3, and 6 months after operation were 15.6±2.2, 18.5±1.4, 19.3±0.7, respectively. At discharge after operation, the patient’s satisfaction with the outcome of the operation was scored 84.7±11.4. The score of adverse events of radiotherapy at 6 months after operation was 6.5±0.8. During the follow-up, patient had no local recurrence, distant metastasis, or breast cancer related death. Conclusion For breast cancer patients with moderate or greater breast hypertrophy and/or moderate-to-severe breast ptosis, three-pedicle reduction mammoplasty can not only remove the lesions, but also reduce hypertrophic breasts, accomplish the mammoplasty, reduce the radiotherapy complications, and improve the satisfaction and quality of life of patients.