The natural history of low-grade ductal carcinoma in situ of the breast in women treated by biopsy only revealed over 30 years of long-term follow-up.

Background: Opportunities to study the natural history of ductal carcinoma in situ (DCIS) are rare. A few studies of incompletely excised lesions in the premammographic era now recognized as DCIS have provided critical insights into its proclivity for local recurrence in the original site. At the time the biopsies in the current study were originally examined, small DCIS was not diagnosed and, by default, these women were treated by biopsy only.

Methods: The authors report the latest results from a follow-up study, which was published originally in 1982, of 28 women with low-grade DCIS who were treated by biopsy only. These women were from a large, prospectively identified, completely characterized cohort.

Results: Eleven of 28 women developed invasive breast carcinoma (IBC), all in the same breast and quadrant from which their low-grade DCIS biopsy was taken. Seven IBCs were diagnosed within 10 years of the DCIS biopsy, 1 was diagnosed within 12 years of the DCIS biopsy, and the remaining 3 IBCs were diagnosed over 23-42 years. Five of these women, including 1 woman who developed IBC 29 years after her DCIS biopsy, developed distant metastasis, which resulted in death 1-7 years after the diagnosis of IBC.

Conclusions: The natural history of low-grade DCIS can extend greater than 4 decades, with IBC developing at the same site as the previous DCIS in the majority of women. This natural history differs markedly from that of patients with high-grade DCIS and from the outcome of patients with any completely delimited DCIS excised to negative margins.