C. Jillian Tsai, MD, PhD, Discussed Outcomes with SBRT in Lung and Breast Cancer

At the 2021 American Society for Radiation Oncology, CancerNetwork® spoke with C. Jillian Tsai, MD, PhD, a radiation oncologist from the Memorial Sloan Kettering Cancer Center, about the differences seen between patients with non–small cell lung cancer (NSCLC) and breast cancer following treatment with stereotactic body radiation therapy (SBRT). Notably, Tsai stated that patients in the lung cancer group, in particular, were more likely to respond to SBRT than the breast cancer group. She emphasized the importance of expanding the trial in order to better identify which subgroup of patients would most benefit from SBRT.

Transcript:

In this trial, we accrued both [patients] with NSCLC, and breast cancer. They all had oligoprogressive diseases, and they were randomized into 2 groups. One group would continue their standard of care therapy, per physician’s choice. Another group, [was given] up-front radiation therapy to the progressive sites—very targeted radiation—followed by the standard of care therapy. What we found was very interesting; if we look at the group as a whole, combining lung and breast, there is a significant difference. After giving patients SBRT, then targeted radiation to treat the progressive sites, these patients had a longer progression-free survival, compared with the standard of care group. When we separated the lung and breast [groups], looking at them [separately], the lung group was the group that was driving the result. There was a very substantial benefit of adding targeted SBRT radiation therapy to the oligoprogressive disease in the lung group, whereas in the breast cohort, there was really no difference.

There could be several different explanations [for these differences]. First, is that for the lung group, perhaps, maybe their previous lines of systemic therapies were different from the breast cohort. There could [also] be some synergy in their previous systemic therapy with radiation. Another reason could be just because the lung group really had a steadier state of disease with slow progressive disease over time. Whereas the breast patients might have already had multiple dormant pseudo-progressive sites that were not hot at the time of enrollment and randomization. All these other sites might eventually just progress regardless. We are looking into the exact details of these patients and their differences to hopefully find explanations.

We are hoping to expand the trial once we find a subgroup of patients who could potentially really benefit from the technique and hope to take it to a larger study to [examine] this further.

Reference

Tsai J, Yang T, Guttmann DM, et al. Consolidative use of radiotherapy to block (CURB) oligoprogression: Interim analysis of the first randomized study of stereotactic body radiotherapy in patients with oligoprogressive metastatic cancer of the lung and breast. Presented at 2021 American Society For Radiation Oncology; October 24-27 2021; Chicago IL. Abstract LBA-3.