BCC 2021 | St. Gallen Consensus 2021: neoadjuvant and adjuvant therapy for HER2+ breast cancer
The St. Gallen International Consensus Session 2021 was held virtually in March, focused on the optimal treatment of women with early breast cancer. Nadia Harbeck, MD, PhD, LMU Munich, Munich, Germany, shares the discussions that took place regarding the neoadjuvant and adjuvant treatment of patients with HER2-postive (HER2+) early breast cancer. The meeting established a broad consensus that a neoadjuvant approach was optimal in this setting. Some disagreement remained on the best chemotherapy backbone to use with neoadjuvant trastuzumab-pertuzumab dual blockade for HER2+ cancer, with different opinions on the necessity of anthracyclines. The optimal adjuvant regimen for node-positive and node-negative disease was also discussed, as well as the role of neratinib. This interview took place during the 17th St. Gallen International Breast Cancer Conference.
Transcript (edited for clarity)
So I think in St. Gallen now there is consensus that in HER2-positive early breast cancer, we do the neoadjuvant approach, unless it’s a tumor like two centimeters or less, node-negative, where we can take the patient to primary surgery, and then if that diagnosis is confirmed, continue with the APT regimen of 12 times paclitaxel plus trastuzumab for a year. For all other patients, there was broad agreement across the different experts from different nationalities, and even continents, that neoadjuvant therapy would be the way to go...
So I think in St. Gallen now there is consensus that in HER2-positive early breast cancer, we do the neoadjuvant approach, unless it’s a tumor like two centimeters or less, node-negative, where we can take the patient to primary surgery, and then if that diagnosis is confirmed, continue with the APT regimen of 12 times paclitaxel plus trastuzumab for a year. For all other patients, there was broad agreement across the different experts from different nationalities, and even continents, that neoadjuvant therapy would be the way to go.
There was a bit of a discussion on which is the appropriate chemotherapy backbone for the trastuzumab-pertuzumab dual blockade in the neoadjuvant setting. I proposed that we should give less anthracyclines because of the TRAIN2 data and all the evidence that supports an anthracycline-free regimen, like the BCIRG-006 trial or the KRISTINE trial, but there’s colleagues who say that, that all of these trials really don’t confirm for sure that the anthracyclines should not be given and then came patients’ concerns, but also expert concerns from countries where they didn’t have access to dual HER2 blockade that maybe if you don’t have access to the optimal HER2 therapy, you should use an anthracycline-taxane backbone.
So that was basically it, until surgery. And then after surgery for patients with non-pCR, we would recommend to continue with one year of trastuzumab. If the tumor has always been node-negative, and if it’s been node-positive, continue the dual blockade based on the APHINITY data. And for patients with non-pCR continue with TDM1 for 14 cycles based on the KATHERINE trial.
So it’s a pretty uniform schematic of the treatment algorithm. There was a little bit of discussion on the panel then on, I think it was Sunday with regard to the role of neratinib. And because we have our registration in Europe for hormone receptor-positive high-risk patients, and the experts said, well, the data was done based after trastuzumab adjuvant therapy so it does not reflect the gains the patient would get from one year of neratinib after the first year of anti-HER2 blockade if the patient had already seen TDM1 and dual blockade. So that is something that one could mention to the patients, but the experts recognized that that is not a mandatory step of treatment, but rather an offer we could make to high risk, hormone receptor-positive patients.
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