Radiotherapy plus sacituzumab govitecan feasible in metastatic breast cancer

Concurrent administration of sacituzumab govitecan and radiotherapy is well tolerated and does not lead to increased toxicity in patients with metastatic breast cancer, a study has shown.

Thirteen patients with metastatic breast cancer (mean age 54 years) were included in the analysis, and the majority (61.5 percent) had triple-negative breast cancer (TNBC). In total, 19 metastatic sites were irradiated, of which 10 were brain and nine were bone metastases.

Radiation-induced toxicity did not occur, and none of the patients had interruptions in their treatment. Grade 3 to 4 toxicities were limited to neutropenia (15.4 percent).

Furthermore, the median overall survival (OS) from radiotherapy completion was 6 months, with a rate of 45.1 percent at 6 months and 16.9 percent at 12 months.

“This combination may be feasible in metastatic breast cancer patients when clinically indicated,” the investigators said. “Further studies with larger cohorts are necessary to confirm these findings.”

All metastatic breast cancer patients receiving sacituzumab govitecan and undergoing external beam radiotherapy at Institut Curie Hospital in Paris, France, were included in this retrospective, single-centre study. The investigators analysed clinical and pathologic data, treatment details, toxicities graded per CTCAE v5.0, and survival outcomes. They also estimated OS using the Kaplan-Meier method.

“Sacituzumab govitecan, an anti-TROP2 antibody-drug conjugate, is approved for metastatic TNBC from the second-line setting and for HR+/HER2− breast cancer from the third line,” the investigators said.

“Radiotherapy is frequently required in metastatic settings for symptom control, but its combination with sacituzumab govitecan has not been formally evaluated,” they added.