Evaluating the Role of Adjuvant Radiation Therapy in Node-Positive Male Breast Cancer Patients Using the NCDB

Abstract

<h3>Purpose/Objective(s)</h3> The survival benefit associated with adjuvant external beam radiation therapy (EBRT), following mastectomy and breast conserving surgery, in the treatment of female patients with lymph node-positive (LN+) breast cancer is well established. Treatment of LN+ male breast cancer is largely extrapolated from randomized clinical trials and meta-analyses including females only. This study retrospectively examines the impact of adjuvant EBRT, after either mastectomy or breast conserving surgery, in LN+ male breast cancer patients using data from the National Cancer Database (NCDB). We hypothesize that a survival benefit will also be seen in LN+ male breast cancer patients receiving adjuvant EBRT. <h3>Materials/Methods</h3> The NCDB was queried for male patients with a diagnosis of invasive breast cancer who were pathologically node positive from 2004 to 2017. Patients were excluded if they had metastatic disease at time of diagnosis or pathologically node negative disease. We included males irrespective of type of surgery performed, including mastectomy, lumpectomy, sentinel lymph node biopsy, and/or axillary lymph node dissection. Cohorts were separated based upon treatment with or without EBRT. Cox regression was used for multivariate survival analyses taking into account patient's insurance, Charlson-Deyo-Comorbidity score, hormone receptor status, age at diagnosis, number of LNs involved, and if adjuvant chemotherapy and/or hormone therapy were delivered. <h3>Results</h3> A total of 7,558 men were identified, with 3,852 (51%) having received EBRT (cohort 1a) and 3,706 who did not receive EBRT (cohort 1b). See the table below for some of the patient characteristics. Numbers listed in the table represent the total number of patients with percentages of each cohort in parenthesis. Five-year overall survival was 72.3% for those who received EBRT in comparison to 64.6% for those who did not receive EBRT. When using multi-variate survival analysis, the hazard ratio for cohort 1b as compared to cohort 1a was 1.30 (p <0.01), signifying that those who did not receive EBRT were 30% more likely to die in comparison to those who did receive EBRT. <h3>Conclusion</h3> There appears to be an overall survival benefit associated with adjuvant EBRT in LN+ male breast cancer patients, despite those patients presenting with higher stage. Consideration for adjuvant radiation therapy in LN+ male breast cancer patients should be discussed.