One Decade Later: Trends and Disparities in the Application of Post-Mastectomy Radiotherapy Since the Release of the American Society of Clinical Oncology Clinical Practice Guidelines

Purpose In 2001 ASCO published practice guidelines for post mastectomy radiotherapy (PMRT). We analyzed factors that influence the receipt of radiotherapy therapy and trends over time. Methods and Materials We analyzed 8889 women who underwent mastectomy as primary surgical treatment for stage II or III breast cancer between 1995 and 2008 using data from the Kentucky Cancer Registry. We categorized patients according to ASCO group: group 1, PMRT not routinely recommended (T2, N0); group 2, PMRT controversial/evidence insufficient (T1-2, N1); group 3, PMRT recommended or suggested (T3-4 or N2-3). Probability of receiving PMRT was assessed using logistic regression. Results Overall, 24.0% of women received PMRT over the study period. The rates of PMRT for group 1, 2, and 3 were 7.5%, 19.5%, and 47.3%, respectively. Since 2001, there was an increase in the use of PMRT (from 21.1%-26.5%, P