title: Trends in the Application of Postmastectomy Radiotherapy for Breast Cancer With 1 to 3 Positive Axillary Nodes and Tumors ≤5 cm in the Modern Treatment Era: A Retrospective Korean Breast Cancer Society Report.
abstract: Despite high-level evidence, the benefit of postmastectomy RT in these patients in recent years has not been fully elucidated. We investigated postmastectomy radiotherapy (RT) use and evaluated clinicopathologic and treatment factors influencing RT use in Korean women with pT1-2N1 breast cancer.We identified women diagnosed with pT1-2N1 breast cancer between 1994 and 2009 using the Korean Breast Cancer Registry. Factors associated with RT use were evaluated using logistic regression analysis. The median follow-up was 95 months.Of the 6196 women, 11.9% underwent postmastectomy RT. RT was applied more frequently in women with 3 positive lymph nodes (adjusted odds ratio [OR], 2.69) and larger tumors (OR per centimeter, 1.10). RT use was not significantly associated with well-established risk factors (e.g., tumor grade, hormone receptor status, and lymphovascular space invasion). Although RT utilization increased gradually during the study period (OR per year, 1.07), factors associated with RT were similar over time. The estimated 5-year overall survival increased significantly from 84.1% in 1994 to 2000 to 94.6% in 2005 to 2009.This population-based analysis revealed that the indications for postmastectomy RT in pT1-2N1 breast cancer in Korea are based solely on conventional anatomical factors, although their survival has increased significantly in the modern treatment era. There is a significant unmet need for better risk stratification in these patients and for tailored RT with the incorporation of tumor biology-associated factors.
authors.affiliation: From the Department of Radiation Oncology (JSC, YBK), Yonsei University College of Medicine, Seoul; Department of Surgery (JEC), Yeungnam University College of Medicine, Daegu; Department of Surgery (MHP), Chonnam National University Medical School, Gwangju; Department of Surgery (SHJ), Chonbuk National University Medical School, Jeonju, Jeonbuk; Department of Radiation Oncology (BOC), College of Medicine, The Catholic University of Korea, Seoul; Department of Surgery (HSP, SP); and Yonsei Song-Dang Institute for Cancer Research (YBK), Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jee Suk
authors.initials: JS
authors.lastname: Chang
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Choi
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Park
authors.forename: Sung Hoo
authors.initials: SH
authors.lastname: Jung
authors.forename: Byung Ock
authors.initials: BO
authors.lastname: Choi
authors.forename: Hyung Seok
authors.initials: HS
authors.lastname: Park
authors.forename: Seho
authors.initials: S
authors.lastname: Park
authors.forename: Yong Bae
authors.initials: YB
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008408:Mastectomy; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods*; D011878:Radiotherapy / Q000379:methods / Q000639:trends*; D056910:Republic of Korea; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult