Lobular Carcinoma of the Breast—Conservative Local Therapy Still an Option

Abstract & Commentary

Synopsis: Despite its multicentric characteristics, it appears that lobular carcinomas are similar to intraductal carcinomas in their likelihood of being cured or controlled by conservative primary surgery plus radiation therapy.

Sources: Bornstein BA, Moran MS. Int J Radiat Oncol Biol Phys 1996;36:180, abstract #44; Haffy BG, et al. Int J Radiat Oncol Biol Phys 1996;36:214, abstract #112.

The numerous retrospective and randomized clinical trials that have been published and updated over the past decade have led to increased interest in breast preservation for women with breast cancer. By far, the majority of women in these trials have had infiltrating ductal carcinoma. There is often concern expressed whether patients who have infiltrating lobular carcinoma (ILC), or lobular carcinoma in situ (LCIS), as a component of their breast cancer are candidates for breast-conserving local therapy. This concern is related to the fact that lobular carcinoma is largely a multicentric disease; the role of local treatment approaches is not intuitively obvious. Two abstracts presented at the recent meeting of the American Society of Therapeutic Radiology and Oncology (ASTRO) report that these patients have local control and survival rates comparable to patients with infiltrating ductal carcinoma when approached with breast-sparing surgery plus radiation therapy.

In the first report, Bornstein et al from the Joint Center for Radiation Therapy in Boston, reviewed their experience with patients treated between 1970-1986 with conservative surgery and radiation therapy for pure invasive ductal carcinoma (non-ILC, n = 1089), invasive lobular carcinoma (n = 93), or mixed histology (n = 59). Patients with ILC were older (median age, 58 years vs 51 years), had a lower incidence of axillary lymph node involvement (31% vs 38%), and, for patients in whom the margins were evaluable, were more likely to have positive margins (66% vs 39%) than those patients non-ILC. Local recurrence rates at five and 10 years were 8% and 15% for patients with ILC compared with 10% and 13%, respectively, for patients with non-ILC. The survival rates with no evidence of disease and incidence of contralateral breast cancer were also similar for the two histologies. In a multivariate analysis for survival and time to recurrence, histology was not found to be a significant prognostic factor. The authors conclude that the presence of lobular carcinoma should not influence decisions regarding local treatment options.

The second report, by Moran and Hafty, reviewed the Yale experience with conservative surgery and radiation therapy and examined whether the presence of LCIS influenced local control rates and survival. Of their patients treated before 1993, 51 had LCIS as a component of their breast cancer pathology, compared with 1021 patients without LCIS. No patient was treated for LCIS alone. Patients with LCIS as a component of their breast pathology were more likely to have lobular carcinoma (53% vs 4%) than those patients without LCIS. There was no difference in 10-year overall survival rates, distant disease-free survival or local recurrence rates between the two groups.

COMMENTARY

Lobular carcinomas of the breast are relatively uncommon, representing only 5-10% of cases overall. Thus, they comprise a small proportion of the cases reported in any series of patients treated with conservative surgery and radiotherapy. Patients with lobular carcinoma often present with a vague, ill-defined breast mass and often have a false-negative mammogram. These factors, along with a reported increased frequency of multicentricity1 have raised questions whether breast conservation as local treatment is effective for cancers with this histology. The major contraindication to breast conservation is the presence of multicentric disease by palpation or mammogram. These two reports show that despite these concerns, breast-conserving local therapy is as valid an option for these patients as it is for patients with invasive ductal carcinomas.

Similar findings have been reported by Weiss et al,2 from the University of Pennsylvania; Dewar, et al,3 from the Institute Gustave Roussy; and from Sastre-Garau et al from the Institut Curie in Paris, France.4 The latter study is by far the largest experience reported in the literature regarding invasive lobular carcinoma. Their study included 726 women with ILC, 249 women with mixed lobular/ductal histology, and 10,061 cases of non-ILC. Patients with ILC were older, and had slightly larger tumors than those with non-ILC lesions. Axillary involvement was less frequent, and the tumors were of lower grade, and more often estrogen receptor positive in patients with ILC compared with non-ILC cases. Multicentricity was not more common in patients with ILC, and contralateral breast cancer rates were similar between groups. Of the 480 cases treated with breast conservation, local recurrence, overall survival, and disease-free survival were not different between patients with ILC and non-ILC histology. Therefore, for any patient with breast cancer, the presence of invasive lobular carcinoma, or lobular carcinoma in-situ should not influence recommendations for local therapy. Decisions regarding the choice of breast conservation vs. mastectomy should be made just as they are for women with infiltrating ductal carcinomas.

References

1. Henderson IC, et al. Cancer of the breast. In Cancer: Principles and Practice of Oncology. eds: DeVita VT, Jr., et al. Philadelphia: Lippincott; 1989:1205.

2. Weiss MC, et al. Int J Radiat Oncol Biol Phys 1992; 23:941.

3. Dewar JA, et al. Cancer 1995;76:2260.

4. Sastre-Garau X, et al. Cancer 1996;77:113.