I posted earlier in this thread regarding worries that Herceptin for early stage bc would set the stage for possible Herceptin resistance later on if one had recurrence. I found the reference I was looking for, in an web chat forum involving breast cancer experts, including Susan Love among others. Following is the pertinant excerpt, and the link if anyone wants to read the whole chat.
Bold emphasis is mine
http:/www.susanlovemd.org/chat_frames_040914.html
Joyce O'Shaughnessy MD:"...With all of our other treatments against breast cancer, whether chemotherapy or hormonal therapy, when cancer progresses through that treatment, we stop that treatment.
Importantly, we may come back if that treatment had initially been effective. If we can take that woman off that particular agent for at least a year, then there's a reasonable chance (though not as high as the first time) that that woman may benefit again from that agent, particularly if it's been 2-3 years since the breast cancer has seen that treatment. If it's initially effective, there's a reasonable change it will be effective again.
Susan Love MD Do you think the cells just recuperate?
Joyce O'Shaughnessy MD Yes. There's evidence that you can see new areas of chromosomes under the microscope by special staining when cells become drug resistant. When you take the chemotherapy drug away, those new areas of the chromosomes disappear over time.
The cells can forget they became resistant. We definitely see that. So we don't know if Herceptin is in the same category. There are laboratory studies that suggest that even though the cancer cells can be growing through the Herceptin, there's a braking phenomenon, meaning that they aren't growing quite as fast, they can be seen slowing them down even though they're not killing them. That can be seen in the laboratory, but we don't have any data in women.
My own personal opinion based on clinical observations is to give woman long breaks off the Herceptin by offering her hormonal therapy if her breast cancer is ER positive. I might use Xeloda, for example, by itself. It's just a pill, women can tolerate it and get great responses from it, and then I might use Herceptin and Taxotere. And if the cancer progresses, I might stop both and use Xeloda by itself, and a lot of times it works and the woman may be off intravenous drugs for a year or so. And if the woman is doing well and her disease progresses, I might offer her participation in a clinical trial. I like to try to get her off the Herceptin if I can for a year or more because I have anecdotal experience of coming back later on with the combination of Herceptin with either Gemzar or Taxol or Navelbine. I've had some women do very well all over again. I don't have reason in my own practice to think Herceptin is that different from any of the other chemotherapy or hormonal drugs. Once the cancer has progressed, I haven't seen any benefit to patients from continuing the Herceptin. But this is just conjecture on my part because we don't have data..."
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