The ways in which patients with breast cancer respond to neoadjuvant chemotherapy will give practitioners a clue as to how they will benefit from radiation therapy (RT), Welela Tereffe, MD, explained during the 2017 OncLive®
State of the Science Summit on Breast Cancer.
This topic is being explored in the ongoing phase III NSABP B-51 trial, which is looking at standard or comprehensive RT in patients with early-stage breast cancer who have undergone surgery and received prior chemotherapy (NCT01872975). Specifically, researchers will evaluate postmastectomy chest wall and regional nodal RT and postlumpectomy regional nodal RT in patients with positive axillary nodes before neoadjuvant chemotherapy, who convert to pathologically negative axillary nodes after the treatment.
Tereffe, who is an associate professor in the Department of Radiation Oncology at The University of Texas MD Anderson Cancer Center, discussed the current state of RT in breast cancer and emphasized the importance of a multidisciplinary approach.
OncLive: Could you provide an overview of your presentation on RT at this State of the Science Summit?
: I reviewed the role of RT in patients who received neoadjuvant chemotherapy, noting that response to neoadjuvant chemotherapy can risk-stratify patients into 2 groups. One group has a low risk of local regional recurrence and would sustain a relatively small benefit from either postmastectomy radiation or—in the breast-conserved setting—from the addition of regional nodal irradiation to the standard whole breast treatment. The other group is a high-risk group that would benefit from escalated radiation to reduce local regional recurrence, metastases, and death from breast cancer.
The primary way that patients are stratified is by nodal response. Patients with a complete response in the lymph nodes are generally at lower risk. However, there are interactions by subtype, and it appears that patients who have triple-negative, estrogen receptor (ER)–negative, or HER2-positive disease have relatively higher rates of local regional recurrence both with and without a complete response to chemotherapy. They are the most likely to be targeted for escalated treatment, even with a good response to chemotherapy.
What should community oncologists take away from your lecture and apply to clinical practice?
The first thing that I would emphasize is that patients who will receive neoadjuvant chemotherapy must be treated in a multidisciplinary fashion that starts at the time of diagnosis. It is important to assure that the staging workup is sufficient for the subsequent decision-making that will flow to the surgeons and the radiation oncologist. Additionally, this is to make sure that there is serial follow-up of patients receiving neoadjuvant chemotherapy to assess response.
Then, a multidisciplinary, collaborative decision-making process for both the type of surgery that will be performed—in terms of the breast surgery and axillary surgery—and the role of RT can follow.
Secondly, for any patient who was initially node-positive prior to neoadjuvant chemotherapy, a referral to a radiation oncologist is appropriate. In addition, for any patient that remains node-positive after neoadjuvant chemotherapy, RT is absolutely indicated.
It seems that the importance of a multidisciplinary approach has been emphasized in recent years. How does this better serve the patient?
Coordinated care results in better outcomes, so having everyone who will have an impact on the patient's care involved in the process is beneficial. This includes having the diagnostic imaging specialist, the pathologist, the radiation oncologist, the medical oncologist, the surgeon, and the plastic surgeon involved from the beginning to assure that the patient gets the most rational, coordinated treatment possible. As a general principle, this is a good approach to follow. In patients who receive neoadjuvant chemotherapy, it is of critical importance because significant information is lost without multidisciplinary evaluation from the beginning. Inappropriate or inadequate neoadjuvant chemotherapy is actually worse than upfront surgery.
In the worst-case scenario, patients who are either lost to follow-up or received a truncated course of chemotherapy, and don't subsequently complete that treatment after surgery, are probably worse off than if they had received upfront surgery and at least had their definitive treatment.
What do you envision for the role of RT in this field moving forward?
Much like how systemic therapy is being targeted to the right patients, we can escalate treatment in those patients who both need and would benefit from RT. We de-escalate treatment in patients who don’t need or wouldn’t benefit from it. Then we’ll focus our clinical trials on patients who clearly need escalated therapy but don't benefit from what is currently available.