Can intraductal breast carcinoma be excised completely by local excision? Clinical and pathologic predictors

Microscopic evaluation of excised intraductal breast carcinoma (DCIS) specimens using a serial subgross technique reveals that in many patients the lesion is larger than expected, often making complete excision impossible with less than a true quadrantectomy. Data is presented on 181 patients with DCIS in whom the initial biopsy was performed using a more cosmetic wide local excision rather than a true quadrantectomy.

Clear margins were defined as no tumor within 1 mm of any inked or dyed margin. All of these patients subsequently underwent mastectomy or reexcision of the initial biopsy site. This allowed pathologic evaluation for residual disease.

At mastectomy or reexcision, 76% of patients with initially involved margins had residual DCIS, as did 43% of patients with initially clear margins (P < 0.0001). Larger tumor size was a statistically significant predictor of initial margin involvement and residual DCIS (P < 0.05). Patients with comedo-DCIS had a greater tendency toward positive initial histologic margins and residual DCIS, but this trend was not statistically significant (P < 0.1).

DCIS presents major problems to both surgeons and pathologists. It is difficult to excise completely using a wide local excision. Histologically negative margins do not guarantee that residual DCIS has not been left behind. Inadequate excision of the primary lesions may be the most important cause of local failure after conservative treatment for intraductal breast carcinoma.