Welcome to Breaking Boundaries in Breast Cancer on ReachMD, sponsored by Lilly. On this program, we’ll hear from Dr. Terry Mamounas, Medical Director for the Comprehensive Breast Program at Orlando Health, University of Florida Health Cancer Center. Dr. Mamounas is here to share some advancements in early breast cancer that were featured at the 2020 San Antonio Breast Cancer Symposium. Let’s hear from him now.
There have been several presentations at the 2020 San Antonio Breast Cancer Symposium that actually were impactful in the treatment of early-stage breast cancer. Perhaps the most impactful was the RxPonder trial, that, as we know, randomized patients with one to three positive nodes, and an Oncotype score of 0 to 25, to receive endocrine therapy plus chemotherapy, versus endocrine therapy alone. And the overall findings of the study showed that there was a small benefit, in terms of chemotherapy plus endocrine therapy versus endocrine therapy alone, but that benefit essentially was exclusively seen in the premenopausal cohort of patients, and there was an interaction between menopausal status and benefit from chemotherapy. So there was no benefit in postmenopausal women with a recurrence score of 0 to 25, but there was significant benefit in the premenopausal cohort of women with recurrence score of 0 to 25, and these results will be impactful on how we treat patients in the clinic on Monday morning. In terms of other trials that may have some impact in terms of surgical trials, the RISAS trial was the trial looking at radioactive iodine insertion in the axillary lymph nodes that are involved at the time of diagnosis and before neoadjuvant therapy, and retrieval of the involved lymph nodes, based on the radioactivity of the radioiodine seed. This approach now has been labeled targeted axillary lymph node dissection, resulting in higher accuracy of identifying the involved lymph nodes, and decreasing the false negative rate of the sentinel lymph node biopsy after the neoadjuvant chemotherapy, and the false negative rate of the targeted axillary dissection with a radioactive iodine seed retrieval was 3.5% in the trial, which is actually very low. It is good assurance that this is a good approach in the stage of the axilla that is in both before the neoadjuvant chemotherapy stays in it, after the neoadjuvant chemotherapy. Several other trials looking at adjuvant therapy for DCIS were discussed. The IBIS-II the results comparing anastrozole to tamoxifen were presented. This one updated results that unfortunately continued to show no significant benefit for anastrozole over tamoxifen, even with about eleven years follow-up, and this was similar to the previous disclosure of this trial, with seven years of follow-up. And this is also actually not confirming what we have seen in the NSABP B-35 trial when anastrozole favored tamoxifen, particularly women under the age of 60, which of course all were post-menopausal women. And we’ve seen similar radiotherapy trials also being disclosed in San Antonio and updated the PRIME II trial, which is a trial looking at the radiotherapy versus no radiotherapy for patients that have localized, invasive, ER positive, HER2 negative breast cancer, older patients — 65 years or older — to see whether this improves local control and also whether it improves survival, and that surprisingly, this data continued to show that the addition of radiotherapy improves local control, but it does not change survival, because most of the events in these patients are deaths from other causes, not breast cancer. And the interesting trial, also for noninvasive breast cancer, was presented by Boon Chua, that actually, for patients with DCIS, asked the question, what is the role of the boost in patients that have lumpectomy, receive radiotherapy, and also what is the role of hyperfractionation versus conventional fractionation, and the bottom line was that the boost improves local control significantly, but hyperfractionation was not any different than traditional fractionation in terms of both safety and efficacy. And I think these are important confirmatory findings for DCIS patients, that we have already known for invasive breast cancer patients.
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