Intraoperative radiotherapy viable for certain patients with breast cancer

In Clinical Trials by Barbara Jacoby

By: Jennifer Southall

From: healio.com

Intraoperative radiotherapy remains a viable option for patients with low-risk breast cancer, according to a presenter at Miami Breast Cancer Conference.

“Intraoperative radiotherapy has been used for at least 10 to 15 years and, in appropriately selected patients, published results of the treatment are quite good,” Frank A. Vicini, MD, FACR, FABS, FASTRO, radiation oncologist at 21st Century Oncology, said during his presentation. “Local recurrence rates are about 2.7% at 5 years, which is what we have seen with many of the phase 3 trials of partial breast irradiation.”

However, controversy surrounds the use of intraoperative radiotherapy (IORT).

Editorials and debates have focused on appropriate duration of follow-up and whether extremely low-risk patients should be treated, Vicini said. Moreover, 20% to 25% of patients receive whole breast irradiation, and there are no standard metrics to evaluate the technique.

In 2016, American Society for Radiation Ooncology addressed the use of IORT for the first time in published guidelines.

“The recommendation truly provided an updated clinical guidance regarding the use of IORT for radiation oncologists and other specialists participating in the care of [patients with] breast cancer,” Vicini said.

The ASTRO consensus statement lists three distinct patient subgroups for use of accelerated partial breast irradiation outside of a clinical trial: a suitable group, a cautionary group and an unsuitable group.

Regarding IORT, the updated recommendations include counseling patients on the higher risk for ipsilateral breast cancer recurrence vs. whole breast irradiation, monitoring local control and toxicity through low-energy radiograph IORT, and limiting IORT to women with invasive cancer who are deemed suitable.

The ELIOT trial compared the use of IORT vs. external radiation among 1,305 patients with early breast cancer. At a median follow-up of 5.8 years, 35 patients in the IORT group had an ipsilateral breast cancer recurrence compared with only four patients in the external radiation group. Five-year survival rates between the two groups were comparable —96.8% with IORT vs. 96.9% with external radiation.

“[Although] these results have been published for years now, the important point is that when selecting patients considered to be in the ‘suitable category,’ the risk for local recurrence was very low within 5 years,” Vicini said.

ASTRO is expected to update the guidelines on IORT use later this year.

“We are anticipating the results from the RAPID and NSABP B-39 trials,” Vicini said. “Until then, the consensus panel guidelines provide contemporary recommendations on the optimal use of IORT, and should still be followed until the data from these trials become available.”