Subclinical ductal carcinoma in situ of the breast. Treatment by local excision and surveillance alone.

BACKGROUND. Mammography has led to earlier detection of subclinical ductal carcinoma in situ (DCIS) of the breast either as nonpalpable calcifications or as an incidental finding in a biopsy performed for another reason. Many women in whom DCIS was detected early may not be destined to have an invasive carcinoma. How should subclinical DCIS be treated if that is the case? What is the role of excision and surveillance only as an alternative to mastectomy or irradiation? METHODS. All patients with DCIS detected as nonpalpable calcifications or as an incidental finding were eligible for this study. Diagnosis was confirmed, and the histologic subtype was determined. Results of postbiopsy mammography confirmed excision of calcifications; wide local reexcision and assessment of margins was also performed in most patients. The maximum diameter of calcifications considered suitable for this treatment was 25 mm. RESULTS. Between 1978 and 1990, 70 women (72 breasts) were entered into this study (mean follow-up time, 49 months; median follow-up time, 47 months). Of this group, 66% were detected as calcifications and 33% were detected as incidental findings. The recurrence rate was 15.3%. All but one of the patients who experienced a recurrence had the comedo type of DCIS as the initial lesion. Each of the recurrences was of the comedo type. All but one recurrence was at the same site as the primary lesion. None of the patients with DCIS as an incidental finding experienced a recurrence. CONCLUSIONS. Excision and surveillance is a reasonable alternative to mastectomy or irradiation for selected women with DCIS that presents as nonpalpable calcifications or as an incidental finding.