A NEW study has highlighted the critical role of restaging MRI in predicting oncologic outcomes for patients with locally advanced rectal cancer treated with total neoadjuvant therapy (TNT). The research, a secondary analysis of the OPRA trial, found that MRI could help stratify patients into clinical response categories that are predictive of organ preservation, local regrowth, and survival outcomes.
The OPRA trial, which ran from 2014 to 2020, randomised patients with stage II or III rectal adenocarcinoma to undergo either induction or consolidation TNT. Restaging MRI was performed an average of 8 weeks after treatment to assess clinical response. Radiologists classified patients as having a complete clinical response (cCR), near-complete clinical response (nCR), or incomplete clinical response (iCR).
The study revealed that patients with a cCR had a significantly higher rate of organ preservation (65.3%) compared to those with nCR (41.6%). Furthermore, five-year disease-free survival was 81.8% for cCR patients, 67.6% for nCR, and 49.6% for iCR patients, with significant differences in overall survival and recurrence-free survival observed across these groups.
Importantly, the study also identified key MRI features associated with residual disease (RD). Restricted diffusion and abnormal nodal morphology were independently linked to a higher likelihood of residual tumour, offering valuable insights for refining patient selection for nonoperative management.
These findings suggest that restaging MRI could be a crucial tool in guiding treatment decisions, improving outcomes, and supporting organ-preserving strategies for rectal cancer patients.
Reference
Williams H et al. MRI Predicts Residual Disease and Outcomes in Watch-and-Wait Patients with Rectal Cancer. Radiology. 2024;312:3.
