M. Zamanian1, A. Soran1, M. K. Wright1, C. Thomas1, G. M. Ahrendt1, M. Bonaventura1, E. J. Diego1, R. R. Johnson1, P. F. McAuliffe1, K. McGuire1 1University Of Pittsburgh School Of Medicine,Division Of Surgical Oncology, Department Of Surgery,Pittsburgh, PA, USA 2Magee Women’s Hospital Of UPMC,Surgical Oncology,Pittsburgh, PA, USA
Introduction: Invasive lobular carcinoma (ILC) is the second most common form of breast cancer, with rates increasing over the past 10-15 years. ILC has unique molecular and clinical characteristics, distinct from invasive ductal carcinoma. Studies of ILC, especially in the premenopausal population, remain limited. We hypothesize that premenopausal patients diagnosed with ILC will present with higher stage tumors and with lower estrogen receptor (ER) expression and will have poorer disease free and overall survival (DFS, OS).
Methods: A retrospective review of a prospectively collected database identified all pre- and postmenopausal patients treated for ILC at a single institution between 2004 and 2010. Patient and tumor characteristics were collected as well as outcome data. Patients whose menopausal status at diagnosis was not recorded were categorized as postmenopausal if they were over age 50 and premenopausal if they were under age 45. Patients age 46-49 were considered perimenopausal and were excluded. ER/PR (progesterone receptor) expression was measured using H-score (H-score = sum of % nuclear staining x intensity 0, 1+, 2+, 3+, giving a range from 0-300). The two groups were compared for differences in presentation and outcome using uni- and multivariate analysis.
Results: 87 premenopausal and 226 postmenopausal patients were treated for ILC during the study period. Demographics were well balanced between the groups with the exception of age (p<0.001). Univariate analysis showed significantly larger tumor size (3.4±2.9 versus 2.5±2 cm, p=0.002), higher clinical stage (p=0.003), higher PR H-score (158±91 versus 121±100,p=0.005), and lower ER H-score (216±67 versus 242±65, p=0.004) in premenopausal versus postmenopausal patients, respectively. Significant differences in treatment with surgical and systemic therapy were also identified (Table 1). HER2 status was similar between groups. Multivariate analysis showed menopausal status to be independently predictive of tumor size (p=0.012), ER and PR (p<0.001) H-score and likelihood of receiving chemotherapy (p=0.013). DFS and OS were similar between the two groups (p=0.14 and p=0.16, respectively).
Conclusion: In this retrospective review of patients with ILC, premenopausal patients presented with larger tumors and with lower ER H-scores than post-menopausal patients. Despite these adverse clinical factors, there were no significant differences in DFS or OS. Premenopausal patients received systemic therapy more often, which may have contributed to equivalent outcomes. Further research is needed to understand how local and systemic therapy affect outcome in premenopausal patients with ILC.
