ASCO 2026 | TBCRC-053: preoperative radiotherapy & pembrolizumab in node-positive TNBC
Shipra Gandhi, MD, MS, Emory University, Atlanta, GA, discusses primary results from the TBCRC-053 (P-RAD) (NCT04443348) trial of no, low-, or high-dose preoperative radiotherapy combined with pembrolizumab and chemotherapy in node-positive triple-negative breast cancer (TNBC). Results demonstrated that the addition of preoperative radiotherapy to pembrolizumab significantly increased tumor T-cell infiltration and yielded high rates of nodal pathologic complete response, with the highest rates observed in the high-dose radiotherapy arm. This interview took place during the 2026 American Society of Clinical Oncology (ASCO) Meeting in Chicago, IL.
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Transcript
So in the TBCRC-053 (P-RAD) trial, the results from the triple-negative breast cancer cohort were presented at ASCO this year. The results were very interesting and showed that radiation arms, both 9 gray and 24 gray, significantly increased the upper quartile T cell infiltration. However, interestingly, we saw that in the 24-gray arm, this improvement in T-cell infiltration did not translate into a similar increase in pCR rate that potentially could be explained by more N3 disease in the 24-gray arm or potentially an immunosuppressive effect of a higher dose of radiation...
So in the TBCRC-053 (P-RAD) trial, the results from the triple-negative breast cancer cohort were presented at ASCO this year. The results were very interesting and showed that radiation arms, both 9 gray and 24 gray, significantly increased the upper quartile T cell infiltration. However, interestingly, we saw that in the 24-gray arm, this improvement in T-cell infiltration did not translate into a similar increase in pCR rate that potentially could be explained by more N3 disease in the 24-gray arm or potentially an immunosuppressive effect of a higher dose of radiation. However, interestingly, the authors also looked at high T cell infiltration and an integrated biomarker of high T cell infiltration and lymph node major pathologic response, which was associated with a pCR rate of 85 to 92%, which is very promising. The limitations of the trial were that the primary endpoint was correlative and it was not powered to look for pCR or for nodal path CR. And secondly, their comparator arm was untreated tumor tissues without pembrolizumab, which makes it difficult to assess the impact of radiation without pembrolizumab. I think the key question would be if this high T cell infiltration would translate into long-term EFS benefit.
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