Case 39: invasive lobular carcinoma

Influence of E-cadherin expression on the mammographic appearance of invasive nonlobular breast carcinoma detected at screening

PURPOSE

To determine whether E-cadherin loss causes nonlobular cancers (NLCs) detected at mammographic screening to have different mammographic appearances than do NLCs with normal E-cadherin expression.

MATERIALS AND METHODS

This study design had hospital ethics committee approval; informed consent was waived. Membranous expression of E-cadherin was assessed immunohistochemically in patients younger than 70 years from a consecutive series of 1944 operable invasive breast cancers. Of those, 276 NLC cases (age range, 45-70 years) were common to a prospectively collected database of breast cancer detected at screening. The mammographic features of 131 NLCs with reduced E-cadherin expression were compared with those of 145 NLCs with normal E-cadherin expression.

RESULTS

NLCs with E-cadherin loss were more likely to manifest as an ill-defined mass and less likely to manifest noncomedo microcalcifications at mammography than were NLCs with normal E-cadherin expression (47 [35.9%] of 131 vs 35 [24.1%] of 145, P = .03; and one [0.8%] of 131 versus 13 [9%] of 145, P = .001; respectively). NLCs with E-cadherin loss were significantly larger (>or=15 mm) than NLCs with normal E-cadherin expression (71 [54.2%] of 131 NLCs vs 57 [39.3%] of 145; P = .01). Both groups had a similar distribution of grade, tumor type, nodal metastases, and vascular invasion.

CONCLUSION

Invasive NLCs with reduced E-cadherin expression detected at screening are more likely to appear as ill-defined masses and less likely to manifest noncomedo microcalcifications than are NLCs with normal E-cadherin expression. NLCs with reduced E-cadherin expression appear to have mammographic features that make them difficult to detect at small sizes.

Outcomes of breast-conservation therapy for invasive lobular carcinoma are equivalent to those for invasive ductal carcinoma

BACKGROUND

Breast-conservation therapy (BCT), including wide local excision and postoperative irradiation, is considered standard treatment for early-stage invasive ductal carcinoma (IDC). The use of BCT in patients with invasive lobular carcinoma (ILC) has been questioned because of concerns regarding ipsilateral breast recurrence and risk of bilateral breast cancer. We evaluated our institutional experience with BCT and compared treatment outcomes for ILC with those for IDC.

METHODS

A review of our BCT database revealed 84 patients with ILC and 1,126 with IDC with stage I or II disease treated with BCT and radiation between 1976 and 1999. We evaluated local-regional recurrence, disease-specific survival, and contralateral breast cancer rates in both groups.

RESULTS

The 5- and 10-year local-regional recurrence rates for the ILC group were 1% and 7%, respectively, and 4% and 9%, respectively, for the IDC group (P = .70). There were no significant differences in the 5- and 10-year disease-specific survival rates between the groups. Contralateral breast cancer occurred in 11.3% of patients with IDC and 11.9% of patients with ILC.

CONCLUSIONS

BCT achieves similar local-regional control and survival outcomes in selected patients with ILC or IDC. Breast-conservation therapy is an appropriate treatment strategy for patients with early-stage invasive lobular carcinoma.