[309] Adenoid Cystic Carcinoma of the Breast: Clinicopathologic and Molecular Analysis of 56 Cases

Xiaoli Zhu, Jieqing Chen, Yan Xing, Constance T Albarracin, Yijue Zhao, Pulivarthi H Rao, Xiaoxian Li, Diana Bell, Adel El-Naggar, Susan C Abraham, Yun Wu. UT MD Anderson Cancer Center, Houston; Cancer Hospital, Fudan University, Shanghai, China; Texas Children's Hospital, Houston

Background: Adenoid cystic carcinoma (ACC) is a rare basal type of mammary gland malignancies with relatively good prognosis, representing only about 0.1% of all primary breast carcinomas. Except for the population-based study, the largest clinical series in the English literature includes fewer than 30 cases. The clinicopathologic features, molecular abnormalities, and clinical outcomes of this rare entity are not fully elucidated.
Design: We studied 56 primary ACCs of the breast from a single institution. The tumors were graded histologically based on the presence and extent of the solid component (Hum Pathol; 18:1276-81). Grade I: no solid component; grade II: solid component comprising ≤30% of the tumor; grade III, solid component >30% of the tumor. Cytogenetic FISH analysis for MYB-NFIB gene fusion, commonly seen in ACC of the head/neck region, was performed using the published methods (Clin Cancer Res; 16:4722-31). Clinicopathologic features were correlated with clinical outcome.
Results: Patients ranged from 33 to 87 years (median: 60 years). Tumor size ranged from 0.8 to 25 cm (median: 2.4 cm). Three patients (5%) had regional lymph node metastasis at presentation. Clinical follow-up was available in 33 patients, with a median follow-up of 72 months. Twelve of 33 (36%) experienced distant recurrence. The 5-year and 10-year overal survival (OS) and recurrence-free survival (RFS) rates were 86%/68% (OS/RFS) and 62%/47%, respectively. Statistical analysis showed that older age (≥ 60 years) and presence of regional node metastasis at presentation were significantly associated with poor OS (p=.05 and < .001) and RFS (p = .009 and <.001) (Figure 1). In addition, patients with grade III tumors were more likely to have lower OS and RFS rate than patients who had grade I or II tumors; although the differences were not statistically significant (p = 0.31 for OS and p = 0.79 for RFS) due to limited sample size. MYB-NFIB gene fusion was identified in 3 of 8 cases for which FISH study was performed.
Conclusions: Not all mammary ACCs have good prognosis. Old age, nodal metastasis at presentation and high histologic grade are poor prognostic indicators in this rare type of breast cancers.

Category: Breast

Monday, March 19, 2012 1:00 PM

Poster Session II # 76, Monday Afternoon


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