Mastectomy rates remain high in Singapore and are not associated with poorer survival after adjusting for age

Patrick M. Y. Chan, Bok Ai Choo, Tianjiao Zhang, Melanie D. W. Seah, Juliana J. C. Chen, Sarah Q. H. Lu, Ern Yu Tan

Recent reports have suggested that women undergoing mastectomy, instead of wide local excision (WLE) for Stage I and II breast cancers have poorer overall survival. This is particularly important in our setting where mastectomy rates are high. In this study, we evaluated the trends in mastectomy and WLE over a 10-year period at a single institute, identified factors more common among women who underwent mastectomy and specifically examined the effect of surgery on outcome. Retrospective review was performed of 2244 women who underwent curative surgery for non-metastatic breast cancer at our institute from 1st January 2001 to 31st December 2010. Mastectomy rates remained high over the 10 years, ranging from 43 to 59 %. Older women, those with symptoms, larger tumours and clinical nodal involvement were more likely to receive mastectomy (P < 0.05). The type of surgery (mastectomy or WLE) did not affect survival in women with ductal carcinoma-in situ, while women with invasive cancer appeared to survive longer when treated with WLE (P < 0.01). Surgery type was not an independent predictor of overall survival and the survival advantage with WLE did not remain after adjusting for age, implying that the effect on survival had been confounded by the fact that older women tended to undergo mastectomy. Mastectomy remains common among our local women, with further studies being needed to evaluate factors involved in decision-making. Older women and those with significant co-morbidities were more likely to undergo mastectomy and this contributed to an apparent survival advantage following WLE.