BY DEBU TRIPATHY | DECEMBER 8, 2011
At the first set of scientific sessions of the San Antonio Breast Cancer Symposium, there was a common theme to many of the presentations. This revolves around the long natural history of hormone receptor-positive breast cancer – what this means is that the risk of recurrence persists for many years – up to 15 to 20 years after surgery.
While chemotherapy, hormonal therapy, and Herceptin in the case of HER2+ cancers, can lower these risks and are standard therapies, the question is what should be done after all treatment is completed? More than half of all the recurrences occur after five years.
Two presentations examined gene signatures obtained on the tumor and showed that genes associated with tumor growth seem to predict early recurrences within a few years, and those that relate to active hormone receptor signaling might indentify those with risk of later recurrences. This needs to be further verified, but it still does not tell us what additional treatment might help.
There are studies that are looking at 10 years of hormonal therapy with aromatase inhibitors compared with the standard five years, but those studies will not yield results for a couple of years. More follow-up from previously as well newly reported trials examining bisphosphonates to prevent recurrences were presented - these are still not showing clear results, with the exception of the ABCSG-12, which is showing a third fewer recurrences with the use of Zometa (zolendronic acid) for three years in premenopausal patients treated with ovarian blockade but without chemotherapy, along with either Arimidex (anastrozole) or tamoxifen. However, the other trials suggest a benefit in the subset of postmenopausal women who are in a "low estrogen environment," where bone turnover is more active.
It is interesting that Dr. Gnant, who presented the ABCSG trial, felt that Zometa was the new standard for care, at least for patients meeting the criteria of that trial, while the commentator, Dr. James Ingle from Mayo Clinic was not as convinced. Still, the whole session pointed to the need to take a very long-term (15- to 20-year) look at outcomes to test new drugs that can improve upon what hormonal therapy does. Also, newer tissue tests can help decide who might be at risk for longer-term recurrence and may be in need of additional treatment.RELATED POSTS