[159] Predictive Markers in Primary Breast Cancer Compared with Lymph Node and Bloodspread Metastases

MF El-Sibai, C Cohen, A Nassar, MT Siddiqui. Emory University Hospital, Atlanta, GA; Mayo Clinic, Rochester, MN

Background: Breast cancer is the most common female cancer in the US, and the main cause of death in women ages 45 to 55. Women with hormone receptor-positive tumors benefit from postoperative Tamoxifen or Aromatase Inhibitors. High levels of HER2 expression identify those patients who might benefit from treatments that target HER2. Among women with metastatic breast cancer, the predictive markers may be different from the primary tumor. We compared predictive markers: Estrogen Receptor (ER), Progesterone Receptor (PR) and HER2 of primary breast carcinomas with those of lymph node (LN) and blood spread metastases (BM).
Design: This study includes 66 women between the ages of 28 to 86 years. Forty-nine patients had LN metastases and twenty-eight patients had BM. ER, PR and HER2 were performed on available aspiration cell blocks on metastatic lesions and primary tumor core biopsies using FDA approved antibodies and HercepTest (Dako). ER and PR were positive when >/=10%. Her2 was positive (amplified/expressed) when 3+ >30% by immunostain or >2.2 by FISH.
Results:

Comparisons	N	Overall agreement %	Kappa	Positive, Breast	Positive, LN	P Value
Breast ER vs. LN ER	42	76.2	0.52	64%	55%	0.57
Breast PR vs. LN PR	42	73.8	0.48	48%	26%	0.06
Breast HER2 vs. LN HER2	39	59.0	0.28	8%	26%	0.07
Breast FISH vs. LN FISH	10	70.0	0.46	30%	30%	0.39
Comparisons	N	Overall agreement %	Kappa	Positive, Breast	Positive, BM	P Value
Breast ER vs. BM ER	19	68.4	0.30	79%	58%	0.45
Breast PR vs. BM PR	18	61.1	0.28	61%	33%	0.31
Breast HER2 vs. BM HER2	17	52.9	0.28	24%	24%	0.45
Breast FISH vs. BM FISH	4	75.0	0.50	50%	25%	0.32
Comparisons	N	Overall agreement %	Kappa	Positive, LN	Positive, BM	P Value
BM ER vs. LN ER	12	33.3	0.00	50%	33%	0.92
BM PR vs. LN PR	12	33.3	0.00	50%	17%	0.57
BM HER2 vs. LN HER2	11	36.4	0.00	9%	18%	0.57
BM FISH vs. LN FISH	1	-	-	-	-	-

Conclusions: All three predictive markers are similar in the primary and two metastatic sites (lymph node, bloodspread). Only in primary vs. lymph node metastases is there a tendency for PR and HER2 (P values 0.06, 0.07) to be different. For HER2, the majority of lymph node metastases are in cell blocks (FNA), fixed in ethanol rather than formalin, which may have caused false positive HER2 expression.
Category: Breast

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 67, Tuesday Morning