Reassessing the risks: toxicity of stereotactic ablative radiotherapy after bevacizumab in oligometastatic ovarian cancer-a new perspective for radiation oncologists?

OBJECTIVE

The aim of this report was to analyze the sub-group of oligometastatic ovarian cancer patients from the large prospective MITORT3/RAD study who underwent stereotactic body radiotherapy and had received bevacizumab treatment.

METHODS

A pooled analysis of the MITORT3/RAD database, focusing on oligometastatic patients with ovarian cancer who received stereotactic body radiotherapy treatment and bevacizumab within 12 months prior to radiotherapy, was performed. The toxicity profile of this patient sub-set, together with the response and outcomes, was then evaluated.

RESULTS

Among 219 patients included in the database updated in February 2025, 41 patients accounting for 68 lesions were included in the analysis. Overall, 26 patients were previously treated with more than 1 systemic regimen. All patients received bevacizumab before stereotactic body radiotherapy, within 12 months before stereotactic body radiotherapy: in particular, 23 patients up to 3 months before and the others up to 12 months before. Only 1 patient had received a previous radiotherapy treatment. Of the 68 lesions, 44 were lymph nodes and 24 parenchymal ones, mainly located in the abdominal (27/68), pelvic (20/68), and thoracic (11/68) districts. Doses ranged from 20 Gy in a single fraction to 50 Gy in 5 fractions according to the site of metastases and constraints to organs at risk. Only 8 patients experienced a total of 15 acute toxicities, all of which were below grade 3. The most common were upper gastro-intestinal issues (4 cases), pain (4 cases), and asthenia (3 cases). Only 1 patient experienced a late toxicity: a grade 2 intestinal sub-occlusion in a patient treated with stereotactic body radiotherapy for 2 abdominal nodal lesions, receiving 40 Gy in 5 fractions. With an actuarial median follow-up of 28 months (95% confidence interval 20.0 to 35.4 months), we registered a 1- and 2-year local control of 82.2% and 73.3%, respectively.

CONCLUSIONS

Stereotactic radiotherapy delivered within 12 months of bevacizumab appears safe and well-tolerated in oligometastatic ovarian cancer, with no grade ≥3 toxicities and preserved quality of life. These results address a major gap in evidence and support stereotactic body radiotherapy as a potential therapeutic option in this challenging clinical setting.