Does locoregional radiation therapy improve survival in breast cancer? A meta-analysis

Purpose: Recent randomized trials in women with node-positive breast cancer who received systemic treatment report that locoregional radiation therapy improves survival. Previous trials failed to detect a difference in surviv al that results from its use. A systematic review of randomized trials that examine the effectiveness of locoregional radiation therapy in patients tr eated by definitive surgery and adjuvant systemic therapy was conducted. Methods: Randomized trials published between 1967 and 1999 were identified through MEDLINE database, CancerLit database, and reference lists of releva nt articles. Relevant data was abstracted. The results of randomized trials were pooled using meta-analyses to estimate the effect of treatment on any recurrence, locoregional recurrence, and mortality. Results: Eighteen trials that involved ct total of 6,367 patients were iden tified. Most trials included both pre- and postmenopausal women with node-p ositive breast cancer treated with modified radical mastectomy. The type of systemic therapy received, sites irradiated, techniques used, and doses of radiation delivered varied between trials. Data on toxicity were infrequen tly reported. Radiation was shown to reduce the risk of any recurrence (odd s ratio, 0.69; 95% confidence interval [CI], 0.58 to 0.83), local recurrenc e (odds ratio, 0.25; 95% CI, 0.19 to 0.34), and mortality (odds ratio, 0.83 ; 95% CI, 0.74 to 0.94). Conclusion: Locoregional radiation after surgery in patients treated with s ystemic therapy reduced mortality. Several questions remain on how these re sults should be translated into current-day clinical practice. (C) 2000 by American Society of Clinical Oncology.