Preoperative MRI assessment of rectal cancer for predicting metastasis-free survival—a post hoc analysis of a randomized controlled clinical trial
摘要
This study aimed to evaluate preoperative MRI risk factors for metastatic disease in patients who underwent neoadjuvant chemoradiotherapy (nCRT) and curative surgery, followed or not by adjuvant chemotherapy (ChT).
Materials and methodsSingle-center post hoc analysis of a randomized clinical trial data to evaluate the effect of adjuvant ChT in comparison to observation in patients with rectal cancer receiving nCRT and surgical resection. Preoperative MRI variables were retrospectively reviewed by three observers. Clinical, surgical, and pathological variables were included in univariate and multivariate analysis, and metastasis risk was assessed. A subgroup analysis was further performed to evaluate the effect of ChT on metastasis incidence in both good and poor responders to neoadjuvant treatment.
ResultsA total of 132 patients (54% female, median age 55 years) were included. Poor mrTRG (HR = 2.53, 95% CI 1.32–5.65) and stage pIII disease (HR 1.94, 95% CI 1.09–3.45) were associated with increased metastatic risk. Although the rate of metastasis was lower in the treated group (9.1%) than in the control group (26.1%) among the patients who achieved a good response (mrTRG 1-2), the difference was not statistically significant (p = 0.19). The subgroup analysis revealed no difference in metastasis rates between patients with poor response receiving or not receiving adjuvant ChT.
ConclusionResponse assessed by mrTRG is a preoperative prognostic factor associated with increased metastasis-free survival. MRI restaging could not predict the clinical benefits of adjuvant oxaliplatin-based ChT.
Key Points