Breast Cancer—HER2/ER 


Clinicopathological characteristics and treatment outcomes in patients with stage I-III invasive lobular carcinoma of the breast (ILC) treated at the National Cancer Centre Singapore. 

 
Joycelyn Jie Xin Lee, Fuh-Yong Wong, Benita Tan, Swee Ho Lim, Sze Huey Tan, Joanne YY Ngeow, ...
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Abstract Disclosures


Abstract 
e12005
Background: Increasing evidence suggests that ILC differs from invasive ductal carcinoma (IDC) but even within ILC there is significant heterogeneity. We aim to identify prognostic factors in our cohort of ILC patients (pts). Methods: 371 pts with stage I-III ILC diagnosed between October 1991 and May 2015 were included. Cox regression analysis was used to evaluate the association between clinicopathological characteristics, treatment received and survival outcomes. Results: Median age at diagnosis was 54 years (range 33.8-84.9) and most pts were Chinese (77%). 204 (69%) of tumors were ER+/PR+/HER2-, 56 (19%) ER+/PR-/HER2-, 20 (7%) ERany/PRany/HER2+, and 17 (5%) ER-/PR-/HER2- (triple negative). 150 (40.4%) had stage I disease, 114 (30.7%) stage II disease and 107 (28.8%) had stage III disease. 242 pts (65%) had a mastectomy while 129 (35%) had breast conserving surgery. 159 (43%) received chemotherapy (24 as neoadjuvant, 135 as adjuvant), 236 (64%) adjuvant radiotherapy and 306 (82%) adjuvant hormonal therapy. Median overall survival (OS) was 17 years (95% CI 14.3–not estimable). In multivariable analysis, in addition to TNM staging, pts with screen-detected cancers were also shown to have significantly better disease-free survival (DFS) (HR 0.47, 95% CI 0.230–0.975) and OS (HR 0.09, 95% CI 0.012–0.655) compared to those with clinically-detected cancers. Prior use of oral contraceptives (OCP) was also associated with improved DFS (HR 0.22, 95% CI 0.081–0.620) and OS (HR 0.10, 95% CI 0.014–0.744). Among 306 pts who had adjuvant endocrine therapy, 222 (73%) used tamoxifen while 82 used other hormonal options. Use of tamoxifen was associated with a poorer DFS compared to other hormonal adjuvants (HR 2.18, 95% CI 0.936–5.066) although this did not reach statistical significance (p = 0.07). Conclusions: ILC are heterogenous in their clinicopathological characteristics and survival outcomes. Interval cancers are associated with a worse prognosis while OCP use is associated with better survival, though our study is limited by cohort size. Future studies should evaluate molecular heterogeneity to help us better tailor treatment choices.
© 2016 by American Society of Clinical Oncology