Marie-France Savard1, Mark Clemons2, Brian Hutton3, Meshari Jemaan Alzahrani4, Jean-Michel Caudrelier5, Lisa Vandermeer6, Michelle Liu6, Deanna Saunders6, Marta Sienkiewicz6, Carol Stober6, Katherine Cole4, Risa Shorr7, Angel Arnaout8, Lynn Chang5. 1. Department of Medicine, Division of Medical Oncology, The Ottawa Hospital and the University of Ottawa, Ottawa, Canada; Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada. Electronic address: msavard@toh.ca. 2. Department of Medicine, Division of Medical Oncology, The Ottawa Hospital and the University of Ottawa, Ottawa, Canada; Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada. 3. Clinical Epidemiology Program, The Ottawa Hospital Research Institute and University of Ottawa, Ottawa, Canada. 4. Department of Medicine, Division of Medical Oncology, The Ottawa Hospital and the University of Ottawa, Ottawa, Canada. 5. Department of Radiology, Division of Radiation Oncology, The Ottawa Hospital Cancer Centre and the University of Ottawa, Ottawa, Canada. 6. Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada. 7. The Ottawa Hospital, Ottawa, ON, Canada. 8. Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Canada; Department of Surgery, Division of General Surgery, The Ottawa Hospital and the University of Ottawa, Ottawa, Canada.
Abstract
PURPOSE: Radiation therapy (RT) and endocrine therapy (ET) are standard treatments for hormone receptor-positive (HR+) breast cancer after breast-conserving surgery (BCS). However, many older patients are at greater risk of treatment-related toxicities and non-cancer related death, and less likely to benefit from these standard treatments. A systematic review was performed evaluating outcomes of omitting RT or ET in older patients aged ≥50 treated with BCS for lower-risk breast cancer. METHODS: Medline, Embase, and the Cochrane Register of Controlled Trials were queried from 1980 to April 30th, 2020 for randomized controlled studies (RCTs) and prospective cohort studies (PCSs) evaluating omission of RT and/or ET compared to RT plus ET in patients. Meta-analysis was performed using random-effects models with findings reported as risk ratios (RR) with 95% confidence intervals (CI). RESULTS: From 3860 citations, 10 prospective studies met eligibility criteria. Omission of RT alone was evaluated in 7 RCTs (n = 4604) and one PCS (n = 667); omission of ET alone was assessed in 1 PCS (n = 271); and omission of either ET or RT was compared to ET plus RT in 1 RCT (n = 495). Adjuvant RT compared to no RT reduced 5- and 10-year in-breast tumor recurrence [5-year: RR 0.16, 95 %CI 0.09-0.27 l 10-year: 0.28, 95 %CI 0.16-0.5], but had no effect on survival [5-year: RR 0.94, 95 %CI 0.77-1.15; 10-year: 1.01, 95 %CI 0.9-1.12]. CONCLUSION: The current body of evidence suggests that RT can be omitted in older patients with lower-risk disease. However, more trials on the omission of ET are required to better inform treatment decisions.
PURPOSE: Radiation therapy (RT) and endocrine therapy (ET) are standard treatments for hormone receptor-positive (HR+) breast cancer after breast-conserving surgery (BCS). However, many older patients are at greater risk of treatment-related toxicities and non-cancer related death, and less likely to benefit from these standard treatments. A systematic review was performed evaluating outcomes of omitting RT or ET in older patients aged ≥50 treated with BCS for lower-risk breast cancer. METHODS: Medline, Embase, and the Cochrane Register of Controlled Trials were queried from 1980 to April 30th, 2020 for randomized controlled studies (RCTs) and prospective cohort studies (PCSs) evaluating omission of RT and/or ET compared to RT plus ET in patients. Meta-analysis was performed using random-effects models with findings reported as risk ratios (RR) with 95% confidence intervals (CI). RESULTS: From 3860 citations, 10 prospective studies met eligibility criteria. Omission of RT alone was evaluated in 7 RCTs (n = 4604) and one PCS (n = 667); omission of ET alone was assessed in 1 PCS (n = 271); and omission of either ET or RT was compared to ET plus RT in 1 RCT (n = 495). Adjuvant RT compared to no RT reduced 5- and 10-year in-breast tumor recurrence [5-year: RR 0.16, 95 %CI 0.09-0.27 l 10-year: 0.28, 95 %CI 0.16-0.5], but had no effect on survival [5-year: RR 0.94, 95 %CI 0.77-1.15; 10-year: 1.01, 95 %CI 0.9-1.12]. CONCLUSION: The current body of evidence suggests that RT can be omitted in older patients with lower-risk disease. However, more trials on the omission of ET are required to better inform treatment decisions.