Antinuclear

Novel targeted therapies have transformed the treatment landscape for HER2-positive breast cancer, as the risk for recurrence has decreased by more than half.

Melissa Mitchell, MD, PhD, assistant professor of radiation oncology at The University of Kansas School of Medicine, said she has not seen a patient treated for HER2-positive breast cancer at her clinic experience recurrence in the past 6 years.

“The treatment drugs have become so effective that it made us think that maybe we could scale back and spare patients the side effects of radiation,” she said in a press release.

Mitchell and colleagues will conduct a single-arm pilot study to evaluate responses to treatment with or without radiation among nearly 80 women aged 50 years and older with stage I or II, node-negative, HER2-positive breast cancer.

HemOnc Today spoke with Mitchell about how the trial will be conducted, the timeline for results, and the potential implications if this approach is shown to be effective and safe.

Question: How did this trial come about?

Answer: Six years ago, a medical oncologist told me he had never seen a patient with HER2-positive breast cancer develop local recurrence. I set out to find patients who had recurrence in this setting. Approximately 2,000 patients later, I have not seen one, either. Although there are some subtypes — such as triple-negative breast cancer — for which patients do need radiation to prevent recurrence, this population of HER2-positive patients is one I have thought we may be overtreating. The systemic therapy we use works so well, maybe we can scale back therapy and reduce toxicities.

Q: How will the trial be conducted?

A: This is a single-arm pilot study. Our population includes women aged 50 years and older with HER2-positive breast cancer. All patients must have primary tumors smaller than 5 cm, with no evidence of nodal involvement by ultrasound or MRI. All patients are required to undergo neoadjuvant chemotherapy, and we are allowing eligible patients to receive some of the newer chemotherapy regimens Trial participants will choose whether they want to be in the intervention or control groups. We will compare outcomes from three groups: radiation without lumpectomy; radiation plus lumpectomy with sentinel lymph node biopsy to show pathologic complete response; and lumpectomy with sentinel lymph node biopsy to show pathologic complete response but no radiation. Women who omit radiation after lumpectomy will undergo follow-up examinations every 3 months for 5 years. We will collect data about local, regional and distant recurrence at each follow-up visit.