title: Comparison of Adjuvant Radiation Therapy Alone Versus Radiation Therapy and Endocrine Therapy in Elderly Women With Early-Stage, Hormone Receptor-Positive Breast Cancer Treated With Breast-Conserving Surgery.
abstract: BACKGROUND
  Randomized data examining adjuvant radiation therapy (RT) alone in elderly women with low-risk, hormone receptor-positive (HR(+)) breast cancer is lacking. We investigated the outcomes for elderly women treated with adjuvant RT alone versus RT plus endocrine therapy (ET) after breast-conserving surgery.
  
  
  METHODS
  We queried our institutional breast cancer database for the following patients: age > 65 years, stage T1-T2N0, HR(+), and treatment with breast-conserving surgery, including adjuvant RT. The χ(2) analysis identified significant baseline differences between the groups. Cox proportional hazard methods identified predictors of endpoints on multivariate analysis. Kaplan-Meier estimates of survival were compared using the log-rank test.
  
  
  RESULTS
  A total of 504 patients were identified, 311 had undergone RT plus ET (62%) and 193, RT alone (38%). The median follow-up time was 88 months. The RT-alone group versus RT plus ET group had different median age (72 vs.71 years, P < .001), different median tumor size (1 vs. 1.3 cm, P < .001), lower grade (40% vs. 29%, P = .05), and fewer close or positive margins (11% vs. 19%, P = .01). The adherence rate to prescribed ET was 70%. Tumor size predicted an increased risk of distant metastasis (DM) (hazard ratio, 1.96; 95% confidence interval [CI], 1.23-3.13) and worse disease-free survival (DFS) (hazard ratio, 1.86; 95% CI, 1.22-2.86). ET nonadherence versus adherence predicted for risk of DM (hazard ratio, 5.03; 95% CI, 1.98-12.66) and DFS (HR, 4.24; 95% CI, 1.9-10.3). Of the women with DM, 83.8% had tumors > 1 cm in size.
  
  
  CONCLUSIONS
  ET nonadherence and tumor size > 1 cm predicted an increased risk of DM and worse DFS, favoring the addition of ET in this group. However, RT alone for women with tumors less than or equal to 1 cm may be appropriate.
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA. Electronic address: colin.murphy@fccc.edu.
authors: Colin T
authors: CT
authors: Murphy
authors: Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA.
authors: Tianyu
authors: T
authors: Li
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors: Lora S
authors: LS
authors: Wang
authors: Department of Medical Oncology and Clinical Genetics, Fox Chase Cancer Center, Philadelphia, PA.
authors: Elias I
authors: EI
authors: Obeid
authors: Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors: Richard J
authors: RJ
authors: Bleicher
authors: Department of Radiation Oncology, State University of New York Upstate Medical University, Syracuse, NY.
authors: Gary
authors: G
authors: Eastwick
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors: Matthew E
authors: ME
authors: Johnson
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors: Shelly B
authors: SB
authors: Hayes
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors: Stephanie E
authors: SE
authors: Weiss
authors: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors: Penny R
authors: PR
authors: Anderson
mesh_terms: D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D016019:Survival Analysis; D013629:Tamoxifen / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; D013629:Tamoxifen
keywords: Adjuvant radiation alone; Elderly breast cancer; Low risk; Nonadherence; Tumor size less than 1cm