Purpose: It has been hypothesized that wide excision alone with margins > or = 1 cm may be adequate treatment for small, grade 1 or 2 ductal carcinoma in situ (DCIS). To test this hypothesis, we conducted a prospective, single-arm trial.
Methods: Entry criteria included DCIS of predominant grade 1 or 2 with a mammographic extent of < or = 2.5 cm treated with wide excision with final margins of > or = 1 cm or a re-excision without residual DCIS. Tamoxifen was not permitted. The accrual goal was 200 patients.
Results: In July 2002, the study closed to accrual at 158 patients because the number of local recurrences met the predetermined stopping rules. The median age was 51 and the median follow-up time was 40 months. Thirteen patients developed local recurrence as the first site of treatment failure 7 to 63 months after study entry. The rate of ipsilateral local recurrence as first site of treatment failure was 2.4% per patient-year, corresponding to a 5-year rate of 12%. Nine patients (69%) experienced recurrence of DCIS and four (31%) experienced recurrence with invasive disease. Twelve recurrences were detected mammographically and one was palpable. Ten were in the same quadrant as the initial DCIS and three were elsewhere within the ipsilateral breast. No patient had positive axillary nodes at recurrence or subsequent metastatic disease.
Conclusion: Despite margins of > or = 1 cm, the local recurrence rate is substantial when patients with small, grade 1 or 2 DCIS are treated with wide excision alone. This risk should be considered in assessing the possible use of radiation therapy with or without tamoxifen in these patients.