Radiation therapy practice patterns for elderly patients with early-stage breast cancer.

82 Background: Controversy exists regarding the benefit of whole breast radiation (RT) after breast conservation surgery (BCS) in elderly early stage breast cancer patients. We investigated the clinical and pathological characteristics that influence referral patterns and consent for RT. Methods: Between 2006 and 2011, 93 women, aged ≥ 70 were treated with BCS at the University of California Davis Medical Center (UCDMC). Electronic medical records were reviewed to identify pathological and clinical tumor characteristics, including stage, nodal involvement, lymphovascular invasion, margin status and molecular subtype. Patient factors including Karnofsky performance status, Charlson comorbidity index, and distance from UCDMC were recorded. Adjuvant therapy recommendations regarding RT, radiation dose and fractionation, hormonal and chemotherapy, and the ultimate treatment plan were noted. Descriptive statistics were used to characterize the referral pattern data. Patient and tumor characteristics were compared between those referred and not referred for RT using chi-square tests for categorical variables and Student’s t tests for continuous variables. Similar comparisons were also conducted for those who consented and declined RT. Results: Of the 93 women eligible for adjuvant whole breast radiation, 79 (85%) were referred to radiation oncology. Sixty five patients had stage I, 16 had stage II, and 4 had stage III breast cancer. Seventy four patients had a luminal A molecular subtype, 11 of whom declined RT. Hormonal therapy was recommended for 78 patients, of which 11 were not referred to RT. The mean age of those referred to RT was significantly less than those not referred, 76 vs. 81 years, P = 0.006. Mean distance to UCDMC was 17.2 miles for those not referred and 34.4 miles for those referred, P = 0.02. There were no significant correlation between stage, molecular subtype, margin status or lymph node involvement and referral to RT. Conclusions: The majority of elderly patients are referred to RT but increased age and comorbidity were associated with non-referral. Patients’ perception of their own comorbidity, previous experience with RT and the decision to pursue hormonal therapy contributed to patients’ decisions to decline RT.