The relation between the presence and extent of lobular carcinoma in situ and the risk of local recurrence for patients with infiltrating carcinoma of the breast treated with conservative surgery and radiation therapy.

BACKGROUND

When found in an otherwise benign biopsy, lobular carcinoma in situ (LCIS) has been associated with an increased risk of development of a subsequent invasive breast carcinoma. However, the association between LCIS and the risk of subsequent local recurrence in patients with infiltrating carcinoma treated with conservative surgery and radiation therapy has received relatively little attention.

METHODS

Between 1968 and 1986, 1625 patients with clinical Stage I-II invasive breast carcinoma were treated at the Joint Center for Radiation Therapy at Harvard Medical School with breast-conserving surgery (CS) and radiation therapy (RT) to a total dose to the primary site of > or =60 grays. Analysis was limited to 1181 patients with infiltrating ductal carcinoma, infiltrating lobular carcinoma, or infiltrating carcinoma with mixed ductal and lobular features who, on review of their histologic slides, had sufficient normal tissue adjacent to the tumor to evaluate for the presence of LCIS and also had a minimum potential follow-up time of 8 years. The median follow-up time was 161 months.

RESULTS

One hundred thirty-seven patients (12%) had LCIS either within the tumor or in the macroscopically normal adjacent tissue. The 8-year crude risk of recurrence was not significantly increased for patients with LCIS associated with invasive ductal, invasive lobular, or mixed ductal and lobular carcinoma. Among the 119 patients with associated LCIS adjacent to the tumor, the 8-year rate of local recurrence was 13%, compared with 12% for the 1062 patients without associated LCIS. For the 70 patients with moderate or marked LCIS adjacent to the tumor, the 8-year rate of local recurrence was 13%. The extent of LCIS did not affect the risk of recurrence. The risks of contralateral disease and of distant failure were similarly not affected by the presence or extent of LCIS.

CONCLUSIONS

Breast-conserving therapy involving limited surgery and radiation therapy is an appropriate method of treating patients with invasive breast carcinoma with or without associated LCIS. Neither the presence nor the extent of LCIS should influence management decisions regarding patients with invasive breast carcinoma. [See editorial counterpoint and reply to counterpoint on pages 978-81 and 982-3, this issue.]