Different HER2 status on 2 different tumors in the same breast

bkerber

I had a biopsy 10/23 which came back Her2 negative. A few weeks later I had another biopsied which showed Her2 positive. Same breast.
Also, the first biopsy showed er positive, pr negative. The second one showed er positive, pr positive.
Is this possible or could it be an error.

ElaineTherese

Hi!

This variation is entirely possible because biopsies just take samples of the tumors, and tumors are heterogenous, which means that they often contain some cells that have a characteristic and some cells that don't. My cancer was found to be 95% ER, which means that 95% of my cells were receptive to estrogen, and 5% were not.

After your lumpectomy, your surgeon should order a pathology report which will better define your cancer type. Good luck with surgery!

ElaineTherese

Oh, and also, two lumps might have different characteristics, even if they're in the same breast. Sounds crazy, right? But, you'll have a better idea of what you're dealing with after surgery. ((Hugs))

bkerber

Thank you Elaine!

Bejeweled

Mine was like that. I had 2 biopsies on what was felt to be 2 separate masses. One was ER+ PR- HER2+ and the other was ER+ PR- HER2-. After my lumpectomy, the pathologist said that they were actually connected, and it was considered one single focus of disease. My MO asked for repeat HER2 testing, and it came back negative. I don't really know what to think. I don't know how much of the mass was really sampled and if the previous results matter. It's all very confusing.

I start chemo next week and will see the MO and discuss at that point I guess.

bkerber

Thanks for the replies. Just had my lumpectomy. BS will retest to get a better idea of what Im dealing with.

windingshores

I had a positive HER2, an equivocal and a negative. I had a 3rd opinion who tested with 60 cells instead of 20. My tumor was mixed ductal and lobular, with the ductal areas being more intense with HER2. The Oncotype Dx test will also help clear things up for you. That tests on the gene level and I have been told that heterogeneity doesn't affect the results.

I was also told that having a lot of DCIS in a biopsy sample may result in a false positive HER2. I am grateful I got other opinions. Otherwise I would have had unnecessary chemo and Herceptin. I am 5 years out so far.

ElaineTherese

Windingshores is spot-on. Seek multiple opinions before you get sucked into chemo. Hope you're recovering well from your surgery!