Abstract P3-05-14: A neoadjuvant window trial of endocrine response in women with invasive lobular carcinoma

Background:

Patients with invasive lobular carcinoma (ILC) would be expected to have favorable outcomes compared to patients with invasive ductal carcinoma (IDC) given that ILC is more often hormone receptor-positive (HR+), human epidermal growth factor receptor 2 (HER2)-negative, of lower grade, and displays decreased proliferation markers. Based on our preclinical studies showing differential hormone response in HR+ ILC vs. IDC and on recent studies suggesting differences in endocrine treatment response between patients with ILC vs. IDC, we designed a biomarker-driven, neoadjuvant window trial for newly diagnosed women with HR+, HER2-negative ILC. We hypothesize that Ki67 will be reduced by 85% in the fulvestrant arm compared with 60% and 75% reduction in the tamoxifen and anastrozole arms, respectively, and that Ki67 reduction will correlate with alterations in expression of ER and ER-regulated genes. Differential Ki67 effect will serve as a surrogate for outcome of patients with ILC on endocrine therapy.

Trial Design: This multicenter study (NCT02206984) will enroll 150 women with HR+ and HER2-negative ILC. A mandatory research breast tumor biopsy will be performed at baseline. Fifty patients will be randomized to each of three open-label treatment arms for 21 days: fulvestrant (two 250 mg IM injections on both day 1 and day 14), anastrozole (1mg orally daily), or tamoxifen (20 mg orally daily). Biomarkers of response will be assessed on baseline and post-treatment tumor tissue. Patients will proceed to definitive surgery on day 21 after study drug exposure, or they will undergo a second research breast core biopsy if further neoadjuvant treatment is planned.

Eligibility Criteria: Eligible patients include postmenopausal women with newly diagnosed, HR+, HER2-negative ILC (excluding pleomorphic subtype) measuring ≥ 1cm, with adequate organ function, ECOG PS ≥ 2, and agreeable to baseline research breast tumor biopsy.

Specific Aims: The primary endpoint is percent change from baseline to post-treatment Ki67 values in ILC tissue after 21 days of endocrine treatment. Comparisons across study arms will be made using a general linear model adjusting for institutional effect, with 80% power estimated for pairwise comparisons of log2(% staining) between treatment arms, allowing for 10% attrition. Secondary endpoints include post-therapy Ki67, and change in ER and PR protein expression by IHC. Finally, planned correlative studies include evaluation of gene expression, epigenetic markers, and DNA sequence variants in ILC tissues in an effort to identify biomarkers of endocrine response and putative drivers of endocrine resistance in ILC.

Target Accrual: This study will be open to enrollment by August 2015 at the University of Pittsburgh. Additional sites will be opened through the Translational Breast Cancer Research Consortium (TBCRC). We anticipate an accrual rate of 8 patients per month.

(Funding from Susan G. Komen® and AstraZeneca).

Citation Format: Jankowitz RC, McAuliffe PF, Sikora MJ, Butler L, Ahrendt G, Johnson R, Diego E, Bonaventura M, Puhalla S, Lembersky B, Clark B, Brufsky A, Kurland BF, Davidson NE, Dabbs DJ, Oesterreich S. A neoadjuvant window trial of endocrine response in women with invasive lobular carcinoma. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-05-14.

The importance of pre-operative needle core breast biopsy results on resected tissue volume, margin status, and cosmesis

PURPOSE

This study aimed to evaluate the relationship between pre-operative image-guided large needle core biopsy (LNCB) histopathology results and surgical resection volumes in breast conserving surgery (BCS), with attention to both margin status and cosmetic outcome.

METHODS

Breast volumes (BV) were calculated using the elliptical cone based formula on mammography images for each patient. Initial resected volume (IRV), final resected volume (FRV), and resected volume ratio (RVR) were calculated and compared according to histopathological diagnosis and cosmetic outcomes. Final pathology results were classified as benign, high risk lesion (HRL), ductal carcinoma in situ (DCIS), or invasive cancer. The cosmetic results were graded based on the Harvard breast cosmesis grading scale.

RESULTS

A total of 217 women underwent BCS by the same experienced breast surgeon. The resected volumes (mean, cm3) were higher among patients who underwent LNCB than those who did not (54.3 vs 26.5 ;p=0.005). The LNCB diagnoses were 16% benign, 19% HRLs, 16% DCIS, and 49% invasive cancers. Reexcision rates were 15.6% and 25.8% for DCIS and invasive cancer, respectively. Cosmesis was excellent in 79.8%. Age, pathological tumor size, IRV and FRV were different among the benign, HRLs and carcinoma groups (p= 0.001).

CONCLUSION

The diagnosis of carcinoma by LNCB leads to the planning of a wider resection, but the need for reexcision is no different than less resection. HRLs are best approached with diagnostic excision, as there is no strong evidence that larger resections reduce the incidence of involved resection margins.