[121] Pathologic Upgrade (PU) Rates on Subsequent Excisional Biopsy (EXBX) When Lobular Carcinoma In Situ (LCIS) Is Found in a Needle Core Biopsy (NCB) with Emphasis on Radiologic Correlation

Timothy M D'Alfonso, Karin Wang, Ya-Lin Chiu, Sandra J Shin. Weill Cornell Medical College, New York, NY; Cornell University, Ithaca, NY

Background: Management of lobular carcinoma in situ (LCIS) on NCB is uncertain as studies report a wide range of PU (3-35%) in the EXBX. This range can be attributed to the design of individual studies [pre-selection bias, radiologic correlation, and characteristics of LCIS [classical vs. non-classical; nuclear grade; extent; calcifications (calcs), if applicable]. We set out to determine the PU rate when LCIS is found in NCB at our institution.
Design: NCB samples containing LCIS as the most significant lesion in patients (pts) who underwent subsequent EXBX were identified (2001-2011). Microscopic features including architecture (florid vs. non-florid vs. both), nuclear grade, percentage of cores involved by LCIS, concurrent columnar cell lesion (CCL), and the presence/absence of calcs within LCIS were recorded. The most significant lesion was recorded from each corresponding EXBX. PU was defined as the presence of invasive carcinoma, ductal carcinoma in situ (DCIS), and pleomorphic LCIS (in cases where only classical LCIS was present in NCB) in the EXBX.
Results: 62 pts with LCIS in NCB who underwent EXBX were identified. Analyzed as a single group, PU was 11% (7/62). The percentage of cores involved by LCIS was significantly associated with PU (p=0.02). Characteristics present in the NCB such as architectural type of LCIS, nuclear grade, presence of CCL, or presence of calcs within LCIS did not correlate with PU. The results were re-analyzed with radiologic correlation. Of 62 cases, 51 (82%) were targeted for calcs, where 11 (22%) had calcs only in LCIS. Of these 11 cases, 3 (27%) had a PU on EXBX (1-microinvasive carcinoma; 2-DCIS). In 26 cases (51%), targeted calcs were found in both LCIS and benign lesions; of these, 3 (12%) had a PU on EXBX (1-invasive ductal carcinoma, 1-invasive lobular carcinoma, 1-pleomorphic LCIS). Cases of purely incidental LCIS (24/62; 39%) showed a PU of 4% (1/24) (1-DCIS).
Conclusions: PU in EXBX is significant (27%) if the targeted lesion is calcs which are exclusively associated with LCIS. If targeted calcs are found in both a benign lesion as well as LCIS, PU in EXBX remains significant (12%). However, for purely incidental LCIS found in NCB, PU is much lower (4%) and thus, foregoing EXBX may be reasonable in these pts. Our study underscores the importance of radiologic correlation when determining the PU in EXBX for pts with LCIS on NCB.
Category: Breast

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 15, Tuesday Morning

 

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