[194] Lobular Neoplasia on Breast Core Biopsy: Is Routine Excision Indicated? A Study of 353 Cases

AV Florea, NN Esposito, DJ Dabbs, C Zhao. Magee Womens Hospital UPMC, Pittsburgh

Background: Lobular neoplasia (LN) is regarded as a risk indicator for the development of invasive ductal or lobular carcinoma of the breast.The significance of these lesions on core biopsy is controversial, with relatively small sample sizes existing in the literature,and thus the utility of subsequent excisional biopsy (SEB) is debatable.
Design: A computer-based retrospective search was performed for a period of 43 months (January 2006 - July 2009) to retrieve cases of atypical lobular hyperplasia (ALH) and lobular carcinoma in-situ (LCIS) on core biopsy specimens. Exclusion criteria included a synchronous diagnosis of invasive carcinoma (IC) and/or ductal carcinoma in-situ (DCIS).Radiologic findings and data from SEB reports were recorded.Statistical analysis was performed by the Chi-square test using SAS 9.1 software.
Results: 278 cases of ALH, including 73 with atypical ductal hyperplasia (ADH), and 129 cases of LCIS, including 34 cases with ADH on core biopsy were identified in our database.Cases without subsequent surgical follow up were excluded, yielding 240 cases in ALH group(mean age 55.8 years) and 113 cases in LCIS group(mean age 53 years) for analysis.The mean period between core biopsy and SEB was 1.5months .Radiological findings included calcifications (262 cases), mass (65 cases),others (28 cases).DCIS and/or IC were detected at excision in 22.2% (20/90) and 10.3% (27/263) in LN/ADH and pure LN groups, respectively(P=0.004).

Table 1 . Subsequent Excisional Biopsy Findings

	Core Biopsy Diagnosis
Highest-grade diagnosis on excision	ALH N= 178 (%)	ALH/ADH N=62 (%)	LCIS* N=85 (%)	LCIS/ ADH N=28 (%)	Total N=353
LCIS	36(20.2)	5(8.1)	44(51.8)	5(17.9)	90(25.5)
LCIS/ADH	6(3.4)	10(16.1)	12(14.1)	4(14.3)	32(9.1)
ADH	26(14.6)	26(41.9)	4(4.7)	5(17.9)	61(17.3)
DCIS	8(4.5)	5(8.1)	4(4.7)	5(17.9)	22(6.2)
Invasive ductal CA	3(1.7)	2(3.2)	5(5.9)	3(10.7)	13(3.7)
Invasive lobular CA	1(0.6)	3(4.8)	5(5.9)	2(7.1)	11(3.1)
Mixed ILC+IDC	1(0.6)	-	-	-	1(0.3)
Benign or ALH	78(43.8)	11(17.7)	11(12.9)	4(14.3)	104(29.5)

* 2/8 cases of pleomorphic LCIS showed ILC on SEB.


Conclusions: To our knowledge, this is the largest retrospective study on the risk of subsequent neoplasia on excision after a diagnosis of LN on core biopsy. While the risk of DCIS and/or IC on excision is significantly higher in LN with ADH compared with LN alone, the latter is still associated with a significant risk of DCIS and/or IC on excision. These results strongly support that excision is indicated after a diagnosis of LN on core biopsy.
Category: Breast

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 30, Wednesday Morning