Which is the best timing to assess response after chemoradiation in locally advanced cervical cancer (BRILACC)?

The goal is to investigate the best time point for assessing radiological complete response after exclusive chemoradiation in locally advanced cervical cancer (LACC). This is a retrospective single-center study. Seventy-nine patients with LACC, stage IB3-IVA FIGO 2018 treated between January and December 2020 were retrospectively analyzed. All patients received external beam radiotherapy (45 Gy in 25 daily fractions ± simultaneous boost to lymph nodes), and interventional radiotherapy (IRT, 28 Gy/twice/weekly) with concurrent chemotherapy. The radiological complete response evaluation was examined using magnetic resonance imaging (MRI) at three timepoints: (i) before IRT, at the end of external beam radiotherapy, (ii) 3 months following the completion of IRT and (iii) 6 months after IRT. Seventy-nine patients were included. At the three timepoints, the complete response rate increased with 21, 53, and 59 patients reporting a complete response at MRI scan, respectively. Seven patients with partial response at the second assessment had complete response 6 months after treatment completion, overall resulting in 80% clinical complete response. Our findings suggest that 6 months following the end of exclusive treatment for LACC patients is the best time to detect complete radiological response (measured by MRI scan) after chemoradiation. Waiting this period of time before conclusively assessing response would allow for the inclusion of patients who have not yet fully responded at 3 months, while avoiding the performance of salvage therapies too early.