Is pleomorphic lobular carcinoma really a distinct clinical entity?

BACKGROUND

Attempts to define the clinical behavior of pleomorphic lobular carcinoma (PLC) have been limited to small series, and clinical management strategies have yet to be established. We describe our experience with PLC as compared to classic ILC and invasive ductal carcinoma (IDC).

METHODS

From 9/1996 to 5/2003, clinical and histopathologic data for 5,635 patients undergoing primary surgical treatment and sentinel lymph node biopsy for breast cancer were collected. Four hundred eighty one (8.5%) patients were diagnosed with ILC; 3,978 (70.6%) with IDC. Of those with ILC, 356 (74%) patients had material available for pathologic re-review and comprise our study population: 52 were classified as PLC; 298 were classified as classic ILC; and 6 cases were reclassified as IDC. We compared clinical, pathologic, and treatment factors for patients with PLC, ILC, and IDC using the Wilcoxon rank sum and Fisher's exact tests.

RESULTS

PLC were larger than ILC and IDC (20 vs. 15 vs. 13, P < 0.001), had more positive nodes (median 1 vs. 0 vs. 0, P < 0.05) and more frequently required mastectomy (63.5% vs. 38.7% vs. 28.8%, P < 0.001). In addition, more patients with PLC had developed metastatic disease compared to patients with ILC (11.5% vs. 3.7%, P < 0.05).

CONCLUSIONS

These findings suggest that PLC is a distinct clinical entity that presents at a more advanced stage and may require more aggressive surgical and adjuvant treatment.