BACKGROUND - The stratification of ductal carcinoma in situ (DCIS) of the human breast into prognostically relevant categories by size and histologic pattern is a current concern. Few studies have been able to follow women after the identification of any type of DCIS when they have had biopsy only.
METHODS - This is an extension of a follow-up study of a group of 28 women with small, noncomedo ductal carcinomas in situ that were excised by biopsy only, published in 1982. All these women have now been successfully followed for an average of almost 30 years.
RESULTS - The overall risk of development of invasive carcinoma for these women over almost 30 years is nine times that of the general population (95% confidence interval, 4.7-17). This is similar to the 11-fold elevation in relative risk that was determined after about 15 years of follow-up. All invasive carcinomas have developed in the same area in the same breast. There were two women in whom invasive carcinoma developed between 20 and 30 years after initial biopsy. One other woman had an extensive noncomedo DCIS that was identified 25 years after her initial biopsy, but had no evidence of invasive disease.
CONCLUSIONS - The natural history of small, noncomedo DCIS can last over at least 2 decades, with invasive carcinoma developing at the same site in which DCIS was previously discovered in a significant percentage of women (broadly, between 25%-50%). This is quite different from the natural history of comedo DCIS or any type of DCIS treated purposefully by surgery alone.