Dr. Judy C. Boughey presented on neoadjuvant chemotherapy for breast cancer patients at ASCO 2018. Below is the full transcript of the interview.
Boughey: So the work that we presented today at ASCO is work out of the ACOSOG Z1071 study, which was a prospective study looking at women who had node positive breast cancer who were treated with neoadjuvant chemotherapy_-_meaning they received their chemotherapy before surgery. We enrolled those patients on this prospective study, which was looking at them from the time of surgery, at which point they underwent usually a sentinel lymph node surgery and an axillary dissection, and then we followed them in terms of their lymphodema rate.
Looking at the data presented today [at ASCO 2018], we're looking at the 3-year follow-up from this cohort of patients, which is a cohort of high-risk women: they have node positive disease, they received neoadjuvant chemotherapy, and they had a full axillary lymph node dissection, so we know this is a group at a high-risk of developing lymphedema.
In three years, we found that the rates of lymphedema were anywhere in that 38 percent to 58 percent range, depending on whether we went based on volume of the arm, based on measurements, or based on patient symptoms.
What we found: We were looking at the factors that were associated with a higher risk of lymphedema. What we saw was that the patients who had longer treatments with a neoadjuvant chemotherapy (so chemotherapy regimens of greater than 20 weeks) were elevated risk of developing lymphedema compared to those patients who had shorter courses of neoadjuvant chemotherapy. Vast majority of patients in this study did receive both an anthracycline a taxane as that was the standard treatment at the time of this trial.
The other finding from the study was kind of in keeping with what we expected and what we know from other studies, which is that patients who have a higher body mass index (so patients who are obese) have a higher risk of developing lymphedema.
Doximity: What are the key takeaways from the study?
Boughey: I think one of the take-home points from the study is clearly to help us identify those patients that are at the highest risk of developing lymphedema.
We know that those patients who have positive nodes and have been treated with chemotherapy and undergo an axillary lymph node dissection are already at a high risk of developing lymphedema. So, within that group, if they are also obese or have neoadjuvant treatment over a greater than a 20 week period, those are the women that are going to be at the highest risk.
So really what this provides for us is a way to look at a risk-stratified approach to surveillance and prevention. For people that are in those higher-risk categories, we should probably be referring them to lymphedema clinics earlier; they should potentially be followed up with a closer surveillance for the possible development of lymphedema; and then at the early signs of any development of lymphedema, considering referral for some kind of intervention to try to treat the lymphedema.
Doximity: What were some significant findings from the Breast Cancer Genome Guided Therapy (BEAUTY) study?
Boughey: One of the studies we ran at Mayo was the Breast Cancer Genome Guided Therapy study, which looked at women with high-risk tumor biology who were treated with neoadjuvant chemotherapy trying to identify predictors of response, looking at the genetic sequencing of the patient's tumor, and also developing patient-derived xenografts from these patients.
There's been a lot of exciting findings coming out from the BEAUTY study at Mayo; we're hoping soon to launch our second phase of that study and trying to bring in some novel drugs for those patients who have chemotherapy-resistant breast cancer. We know with neoadjuvant chemotherapy that those patients who have an excellent response to chemotherapy do very well. If by the time we get to surgery there is no evidence of disease in the breasts and no evidence of disease in the lymph nodes, those patients are going to do very well from a survival standpoint.
The real focus that we want to focus on now are those patients who have resistant disease_-_those are the patients who have had that treatment with neoadjuvant chemotherapy and yet still have resistant clones in their tumor and have viable cancer cells left. I think this provides us a strategy to identify those patients and look at further research on those patients, look at new drugs for those patients, and to try to improve the outcomes.