Responses

Extract

I thank Dr. Atkins for his response to my editorial (1) on the value of margins as one tries to completely excise ductal carcinoma in situ (DCIS). Dr. Atkins correctly comments that we do not know what proportion of DCIS lesions (if untreated or left behind) will ultimately progress to invasive breast cancer.

Page et al. (2) reported long-term follow-up on 28 patients with low-grade, non-comedo lesions considered benign on original evaluation. None of the patients received any treatment other than biopsy. These patients were accrued during the 1950s and 1960s, at a time when margins were not routinely marked. Some of the lesions may have been excised completely, and others were likely transected. There is really no way to tell. After an average follow-up of almost 30 years, 42% of the patients developed invasive breast cancer, and 22% died of breast cancer (KaplanMeier analysis). When I first looked at these figures, I thought they were quite high. An epidemiologist told me that, considering the long follow-up period, they were relatively low. Regardless of which position one takes, the study by Page et al. clearly shows that not all patients with untreated DCIS go on to develop invasive breast cancer. If these patients had had high-grade lesions, one would expect the percentage of invasive breast cancer and the breast cancerspecific mortality rate to be greater than those reported in this study, which consisted of only patients with low-grade DCIS (3, 4), but it would certainly not reach 100%.