Does adjuvant radiation therapy benefit women with small mammography-detected breast cancers?

[摘要] BackgroundWomen with small nonpalpable breast tumours have an excellent prognosis. The benefit of radiotherapy in this group of low-risk women is unknown. MethodsA cohort of 1595 women with stages i–iii invasive breast cancer treated with breast-conserving surgery were followed for local recurrence. Using t-tests, baseline demographic data and tumour characteristics were compared forthe women who had palpable ( n= 1023) and mammography-detected ( n= 572) breast cancers. The 15-year actuarial risk of local recurrence was estimated using a Kaplan–Meier method, stratified for adjuvant radiation therapy (yes or no), tumour palpability (palpable or not), and tumour size (≤1 cm or >1 cm). Hazard ratios (hrs) and 95% confidence intervals (95% cis) were calculated using a multivariate Cox regression model. Results were considered statistically significant if 2-tailedpvalues were less than 0.05. ResultsAmong women with a nonpalpable tumour, the 15-year actuarial rates of local recurrence were, respectively, 13.9% and 18.3% for those treated and not treated with adjuvant radiation therapy (hr: 0.65; 95%ci: 0.40 to 1.06;p= 0.08). Among women with small nonpalpable breast cancers (≤1.0 cm), the rates were 14.6% and 13.4% respectively ( p= 0.67). The absolute reduction in 15-year local recurrence was 11.0% for women with palpable tumours. ConclusionsOur results suggest that women with small (<1 cm) screen-detected nonpalpable breast cancers likely derive little benefit from adjuvant radiotherapy; however, an adequately powered randomized trial would be required to make definitive conclusions.

[学科分类] 肿瘤学

[关键词] Breast cancer;radiation therapy;palpable breast tumours