Effect of acetylsalicylic acid on radiation and cosmetic results after conservative surgery for early breast cancer: a randomized trial.

Background And Purpose: Acetylsalicylic acid (ASA) can reduce the incidence of stroke and myocardial infarction by inhibiting platelet-fibrin thrombi in small blood vessels. To determine if ASA could reduce late effects of radiation therapy mediated by damage to small blood vessels, a prospective, placebo-controlled, double-blind trial was conducted in women with early breast cancer, receiving radiotherapy to the conserved breast.

Materials And Methods: Cosmetic outcome and late radiotherapy effects were recorded prospectively for 186 women with T1 or T2, pathologically node-negative breast cancer treated with breast conservation and randomized to receive ASA (325 mg daily) or placebo for 1 year from the start of radiation therapy. Radiation was a tangent pair to the breast alone delivering a modal dose of 44 Gy in 16 daily fractions in 22-25 days.

Results: Median follow-up is 6.5 years. The use of ASA has not had any effect on the acute (erythema, edema or discomfort) or late (induration, telangiectasia) effects of radiotherapy (all P > 0.10), the patients' or physicians' assessment of the cosmetic outcome (all P > 0.25) or rates of breast recurrence (P > 0.25).

Conclusion: ASA cannot be recommended to improve the outcome of radiotherapy complementing breast conserving surgery.