Lobular invasive pleomorphic breast cancer (BC) should be isolated from the classic type

Abstract

17024 Background: Lobular invasive BC represents between 5 and 10% of all breast tumors. The MD Anderson Hospital has published a study of 122 pt with lobular invasive carcinoma classic type (LIC) with a better long-term outcome than pt with invasive ductal carcinoma (JCO 23:41, 2005). In most papers, the lobular invasive pleomorphic type (LIP) represents a small number of cases and can be easily confused with the NOS carcinoma. The aim of this study is to compare the onset and prognosis of patients (pt) with LIP vs LIC breast cancer. Methods: A search in the IOHM database of 1169 BC was carried out. All of them had been reviewed by two pathologists and classified according the USA Association of Directors of Anatomic and Surgical Pathology's recommendations. The entire cohort was diagnosed and treated at the IOHM. Only those with lobular invasive BC were included in this paper. Results: Between Oct 97 and Nov 06, 116/1169 pt (10%) were diagnosed with invasive lobular carcinoma. Seventy pt (60%) were LIC, and 46 pt (40%) were LIP. Characteristics of the Population: All pt were females. Both groups were comparable in terms of age (median age for both groups = 60 yo) Staging: LIP presented in more advanced stages: A) LIP group: Stage I: 14 pt; II: 22 pt; III: 8 pt; IV: 2 pt B) LIC group: Stage I: 42 pt ; II:13 pt; III: 15 pt; (p:0,001). The LIP group had a higher histological grade (p:0,0001), and more multifocality (p: 0.023), and vascular invasion (p:0,0001) than the LIC group. There were no differences in hormonal receptors status or the ductal extensive component. The retrospective determination of the Her2/neu status is underway. Treatment: Both groups were treated similarly according to the different stages of the illness. Follow-Up: The average follow up time was 23 months (range 4–102) and the LIP group showed a worse prognosis than the LIC group as measured by a higher rate of metastasis (LIP: 12 pt - LIC: 4 pt) (p:0,002) and a higher mortality rate (LIP: 6 pt - LIC: 0) (p:0,003). Conclusions: 1- The LIP carcinoma is a more aggressive variant and has a worse prognosis than the LIC. 2- The incidence for LIP is higher than expected, as it stands for 40% of the total cases in our study. 3- The results justify the establishment of a clear cut differentiation between the classical and pleomorphic types. No significant financial relationships to disclose.