Long-term mortality from cardiac causes after adjuvant hypofractionated vs. conventional radiotherapy for localized left-sided breast cancer

• Published in: Radiotherapy and oncology 2015-01, Vol.114 (1), p.73-78
• Main Authors: Chan, Elisa K, Woods, Ryan, Virani, Sean, Speers, Caroline, Wai, Elaine S, Nichol, Alan, McBride, Mary L, Tyldesley, Scott
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Breast cancer; Breast Neoplasms - mortality; Breast Neoplasms - pathology; Breast Neoplasms - radiotherapy; Cardiac mortality; Female; Heart - radiation effects; Heart Diseases - etiology; Heart Diseases - mortality; Hematology, Oncology and Palliative Medicine; Humans; Hypofractionation; Middle Aged; Radiation Injuries - etiology; Radiation Injuries - mortality; Radiotherapy, Adjuvant - adverse effects; Radiotherapy, Adjuvant - mortality; Risk Factors; Thoracic Wall; Young Adult
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2014.08.021

Abstract Background and purpose Ongoing concern remains regarding cardiac injury with hypofractionated whole breast/chest-wall radiotherapy (HF-WBI) compared to conventional radiotherapy (CF-WBI) in left-sided breast cancer patients. The purpose was to determine if cardiac mortality increases with HF-WBI relative to CF-WBI. Materials and methods Between 1990 and 1998, 5334 women with early-stage breast cancer received post-operative radiotherapy to the breast/chest wall alone. A population-based database recorded baseline patient, tumor and treatment factors. Baseline cardiovascular risk factors were identified from hospital administrative records. A propensity-score model balanced risk factors between radiotherapy groups. Cause of death was coded as breast cancer, cardiac or other cause. Cumulative mortality from each cause after radiotherapy was estimated using a competing risk approach. Results For left-sided cases, median follow-up was 14.2 years. 485 women received CF-WBI, 2221 women received HF-WBI. There was no difference in 15-year mortality from cardiac causes: 4.8% with HF-WBI and 4.2% with CF-WBI ( p = 0.74), even after propensity-score adjustment ( p = 0.45). There was no difference in breast cancer mortality or other cause mortality. For right-sided cases, there was no difference in mortality for the three causes of death. Conclusions At 15-years follow-up, cardiac mortality is not statistically different among left-sided breast cancer patients treated with HF-WBI or CF-WBI.