[190] Needle Core Biopsy Has High Sensitivity for Identifying Breast Papillary Lesions Requiring Surgical Excision: Diagnostic Accuracy in 161 Cases

LJ Elavathil, K Onuma, F Mothafar, N Akhtar-Danesh, K Dhamanaskar, A Lytwyn. McMaster University, Hamilton, ON, Canada

Background: Accuracy of needle core biopsy (CBx) to identify breast papillary lesions (PL) that require surgical excision is controversial. Our objective was to assess accuracy of CBx using 3 thresholds that showed substantial interobserver agreement (kappa 0.72-0.77).
Design: CBx cases with PL were identified from the pathology database. CBx with ADH, DCIS or invasive carcinoma (IC) adjacent to the PL were excluded. At least 2 pathologists independently reviewed each CBx and excision using a diagnostic algorithm and resolved discrepancies by consensus. Pathologists were masked to the excision when reviewing the CBx, and vice versa. Primary outcome was surgical excision with at least ADH (ADH+): papillomas with ADH or DCIS, intraductal papillary carcinoma (IDPC), or IC.
Results: Pathology review identified 164 CBx with PL. There were 151 (92%) excisions, 10 (6%) had clinical follow-up only, and 3 (2%) patients were lost to follow-up. Excisions showed 91 benign papillomas with or without UDH, 7 atypical papillomas, 11 papillomas with DCIS, 17 IDPC, 20 IC, 5 benign breast tissue with no residual lesion.

CBx Threshold	No.	Test performance for identifying PL with ADH+ on excision
		False +	False -	Sensitivity	Specificity	PPV	NPV
Papilloma >10% UDH	89	36	3*	0.95	0.62	0.60	0.95
Papilloma ≥50% UDH	73	21	4**	0.93	0.78	0.71	0.95
Papillary lesion ADH+	62	12	6***	0.89	0.87	0.81	0.93

*1 atypical papilloma, 1 IC & 1 DCIS adjacent to papillomas with UDH; **same, plus 1 papilloma with DCIS, ***plus 1 IC adjacent to papillomas with UDH, 1 papilloma with DCIS

Test indices were similar when patients with clinical follow up were included, and also when the excision showed DCIS or worse, but excluded ADH. Sensitivities are higher if only histologic interpretation of the PL is considered, and cases where radiologic sampling missed adjacent IC and DCIS are not attributed to pathology error.
Conclusions: Excising all PL diagnosed by CBx ensures that all IC and DCIS are excised (sensitivity 100%). However, if 95% sensitivity is acceptable, substantial unnecessary surgeries may be averted if papillomas with no or minimal UDH on CBx do not undergo immediate excision. Follow-up mammography for these cases may safely identify the few additional women requiring surgery.
Category: Breast

Monday, March 22, 2010 8:00 AM

Platform Session: Section C, Monday Morning