講演情報
[E4-2]Pre-Operative Endoscopic Assessment and MRI as Predictors of Pathological Complete Response and Long-Term Survival in Locally Advanced Rectal Cancer after Neoadjuvant Therapy
Trevor M Yeung1, Wing Wa Leung1, Justin Lam1, Prudence Tam1, Julie Ng1, Kaori Futaba1, Sophie S Hon1, Simon Chu1, Esther Hung2, Carmen Cho2, Simon S Ng1 (1.The Chinese University of Hong Kong, 2.Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital)
Aims
We assessed the value of using pre-operative endoscopy and magnetic resonance imaging (MRI) in predicting pathological complete response (pCR) and long-term survival in patients with rectal cancer following neoadjuvant therapy.
Methods
Single-center retrospective analysis of a prospectively maintained database of all patients with stage II/III rectal cancer who underwent neoadjuvant therapy followed by surgery between 2016-2024. Patients underwent pre-operative endoscopic assessment and MRI restaging 4-8 weeks after completion of their neoadjuvant therapy, followed by surgery at 8-12 weeks. Primary outcome was the pCR rate in each endoscopic/MRI category.
Results
203 patients with rectal cancer were treated with neoadjuvant therapy. Overall, the pCR rate was 19.7%. 17 patients had complete clinical response (cCR), with a pCR rate of 76.4%. 42 patients had a near complete response (nCR), with a pCR rate of 47.6%. 130 patients had incomplete clinical response (iCR), with a pCR rate of 0%. Using cCR alone as a predictor of pCR yielded positive predictive value (PPV) 85.4%, negative predictive value (NPV) 65.5%, sensitivity 97.5%, and specificity 32.5%. Combining cCR with nCR yielded PPV 95.1%, NPV 55.9%, sensitivity 84%, and specificity 82.5%. The pCR rates for the different MRI TRG scores were: TRG1 (50%), TRG2 (38.5%), TRG3 (17.3%), TRG4 (9.6%), and TRG5 (25%). 8 -year overall survival rates for cCR, nCR and iCR were 100%, 75.2% and 62.3% respectively (p=0.038).
Conclusion
Endoscopic assessment provides a stronger predictor of pCR compared to MRI alone. Patients who develop cCR or nCR have better long-term overall survival compared to iCR and are good candidates for watch and wait.
We assessed the value of using pre-operative endoscopy and magnetic resonance imaging (MRI) in predicting pathological complete response (pCR) and long-term survival in patients with rectal cancer following neoadjuvant therapy.
Methods
Single-center retrospective analysis of a prospectively maintained database of all patients with stage II/III rectal cancer who underwent neoadjuvant therapy followed by surgery between 2016-2024. Patients underwent pre-operative endoscopic assessment and MRI restaging 4-8 weeks after completion of their neoadjuvant therapy, followed by surgery at 8-12 weeks. Primary outcome was the pCR rate in each endoscopic/MRI category.
Results
203 patients with rectal cancer were treated with neoadjuvant therapy. Overall, the pCR rate was 19.7%. 17 patients had complete clinical response (cCR), with a pCR rate of 76.4%. 42 patients had a near complete response (nCR), with a pCR rate of 47.6%. 130 patients had incomplete clinical response (iCR), with a pCR rate of 0%. Using cCR alone as a predictor of pCR yielded positive predictive value (PPV) 85.4%, negative predictive value (NPV) 65.5%, sensitivity 97.5%, and specificity 32.5%. Combining cCR with nCR yielded PPV 95.1%, NPV 55.9%, sensitivity 84%, and specificity 82.5%. The pCR rates for the different MRI TRG scores were: TRG1 (50%), TRG2 (38.5%), TRG3 (17.3%), TRG4 (9.6%), and TRG5 (25%). 8 -year overall survival rates for cCR, nCR and iCR were 100%, 75.2% and 62.3% respectively (p=0.038).
Conclusion
Endoscopic assessment provides a stronger predictor of pCR compared to MRI alone. Patients who develop cCR or nCR have better long-term overall survival compared to iCR and are good candidates for watch and wait.