The Impact of Hypofractionated Whole Breast Radiotherapy on Local Relapse in Patients With Grade 3 Early Breast Cancer: A Population-Based Cohort Study

• Published in: International journal of radiation oncology, biology, physics Vol. 82; no. 5; pp. 2086 - 2092
• Main Authors: Herbert, Christopher, F.R.C.R, Nichol, Alan, F.R.C.P.C, Olivotto, Ivo, F.R.C.P.C, Weir, Lorna, F.R.C.P.C, Woods, Ryan, M.Sc, Speers, Caroline, B.A, Truong, Pauline, F.R.C.P.C, Tyldesley, Scott, F.R.C.P.C
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.04.2012; Elsevier
• Subjects: Adult; Aged; Analysis of Variance; Biological and medical sciences; Breast cancer; Breast Neoplasms - drug therapy; Breast Neoplasms - epidemiology; Breast Neoplasms - pathology; Breast Neoplasms - radiotherapy; Dose Fractionation; Female; Follow-Up Studies; FRACTIONATED IRRADIATION; FRACTIONATION; Gynecology. Andrology. Obstetrics; HAZARDS; Hematology, Oncology and Palliative Medicine; Humans; Mammary gland diseases; MAMMARY GLANDS; Medical sciences; Middle Aged; MULTIVARIATE ANALYSIS; Neoplasm Grading; Neoplasm Recurrence, Local - epidemiology; Neoplasm Staging; NEOPLASMS; PATIENTS; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Dosage; Retrospective Studies; Risk Assessment; SCHEDULES; Tumors; WOMEN; Radiotherapy; Breast cancer; Dose fractionation; Human; Relapse; Breast disease; Malignant tumor; Fractionated dose; Mammary gland diseases; Cancerology; Treatment; Cohort study; Breast; Early; Mammary gland; Cancer
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2011.01.055

Purpose To determine whether patients with Grade 3 early breast cancer have an inferior rate of local disease control at 10 years with hypofractionated radiotherapy compared with more conventionally fractionated schedules. Methods and Materials Local relapse rates were compared between patients receiving hypofractionated radiotherapy or conventionally fractionated radiotherapy to the whole breast in a population-based cohort of women with early-stage (T1-T2, N0, M0) Grade 3 breast cancers diagnosed between 1990 and 2000 and referred to the British Columbia Cancer Agency. Cumulative rates of local relapse were estimated using a competing risk method, and factors significant on univariate analysis were included with fractionation group in a multivariate model. The primary end point was local control at 10 years. Results A total of 1,335 patients with Grade 3 tumors were treated with adjuvant radiotherapy, 252 with conventional fractionation, and 1,083 with a hypofractionated schedule. The 10-year cumulative incidence of local relapse was 6.9% in the hypofractionated group and 6.2% in the conventionally fractionated group ( p  = 0.99). Conclusions There is no evidence that hypofractionation is inferior to conventional fractionation for breast conserving therapy in patients with Grade 3 breast cancer in this large population-based series after 10 years of follow-up.