Role of postmastectomy radiation therapy in breast cancer patients with T1–2 and 1–3 positive lymph nodes

OBJECTIVE: To evaluate the role of radiotherapy (RT) in overall survival (OS) and disease-free survival in postmastectomy breast cancer patients with tumor size <5 cm, with 1–3 involved axillary lymph nodes (T1–2N1). PATIENTS AND METHODS: We conducted a retrospective study of 89 postmastectomy patients with T1–2N1 disease between 2005 and 2015 at the Radiation Oncology Clinic of Kayseri Training and Research Hospital. Clinicopathologic, demographic, and laboratory findings, as well as treatment regimens were investigated. OS and disease-free survival as well as factors that can be valuable in the prognosis were evaluated. RESULTS: A total of 89 female patients with an average age of 53 years (range: 30–81 years) were included in the assessment. Five-year and 10-year local recurrence rates were found to be 6.6% in the RT group and 7.1% in the non-RT group. In the RT group, the mean OS was 110.3 months and progression-free survival was 104.4 months. In the non-RT group, the corresponding figures were 104.3 months and 92.1 months, respectively. Statistically significant correlation was observed between RT and the American Joint Committee on Cancer stage (P<0.001), histological type (P=0.013), tumor size (P<0.001), and lymph node metastasis (P<0.001). During the assessment, locoregional recurrence and/or distant metastasis occurred in nine patients (10%). Locoregional recurrence was observed mostly in patients with invasive ductal carcinoma, tumor >3.0 cm in size, grade II tumors, and perinodal invasion, and who were premenopausal at the time of diagnosis. CONCLUSION: In T1–2N1 breast cancer patients who underwent modified radical mastectomy, when the effects of postmastectomy RT were evaluated, there were no differences in terms of OS and progression-free survival. In addition, when subgroup analysis was made, in patients with invasive ductal carcinoma, tumor diameter >2 cm, three lymph node metastasis, and stage 2b, postmastectomy RT was seen to be useful.