Postoperative radiation therapy did not lower the recurrence rate among patients with ductal carcinoma in situ that was excised with margins of 10 mm or more. Patients in whom the margin width is less than 1 mm can benefit from postoperative radiation therapy.

DCIS patients with VNPI scores of 3 or 4 can be considered for treatment with excision only. Patients with intermediate scores (5, 6, or 7) show a 17% decrease in local recurrence rates with radiation therapy. Patients with VNPI scores of 8 or 9 exhibit extremely high local recurrence rates, regardless of irradiation, and should be considered for mastectomy.

Background. Infiltrating lobular carcinomas (ILC) represent approximately 10% of all breast cancers. The literature is mixed regarding their prognosis when compared with infiltrating duct carcinomas (IDC). There are few data regarding the treatment of ILC with radiation therapy. Methods. The clinical, pathologic, laboratory, and survival data of 161 patients with ILC were compared with the data of 1138 patients with IDC. Results. ILCs were larger, more difficult to excise completely, and more difficult to diagnose clinically. All prognostic factors measured were more favorable for ILC Nodal positivity for ILC was 32%, compared with 37% for IDC (P = 0.22). The 7‐year disease‐free Kaplan‐Meier survival (DFS) was 74% for patients with ILC and 63% for patients with IDC (P < 0.03). The 7‐year breast cancer specific survival (BCSS) was 83% for patients with ILC and 77% for patients with IDC (P < 0.04). Selected patients with smaller lesions were treated with excison and radiation therapy. Patients with ILC treated with radiation therapy had a better DFS and BCSS than did patients with IDC treated with radiation therapy. Conclusions. ILCs often are homogeneous, small cell tumors of low nuclear grade. Their desmoplastic reaction may be absent or less marked than that of IDC, making them more difficult to palpate and to visualize mammographically. Despite this, they can be treated successfully with either mastectomy or excision and radiation therapy.

Invasive local recurrence after breast-preservation treatment for patients with DCIS is a serious event that converts patients with previous stage 0 disease to patients with disease that ranges from stage I to stage IV. These results, however, indicate that most DCIS patients with local recurrence can be salvaged.

One hundred patients with intraductal breast carcinoma (DCIS) were treated with either mastectomy (49 patients) or radiation therapy (51 patients). All patients underwent axillary lymph node dissection (average number of nodes removed, 16) as part of their treatment. No patient had any positive axillary lymph nodes. There has been one recurrence in each treatment group (median follow-up, 27 months) and no deaths. Intraductal breast carcinoma has little potential for metastasis to axillary lymph nodes.