Predictive Value of Endoscopy in the Identification of Complete Response After Neoadjuvant Therapy for Rectal Adenocarcinoma
Yu Shen, Anqing Lu, Zhao Zhang, Huan Ren, Tinghan Yang, Haining Chen, Ziqiang Wang, Zhu WangBACKGROUND:
Large-scale evidence on the role of endoscopy alone as the assessment tool to identify complete response after neoadjuvant therapy in locally advanced rectal cancer, particularly across different neoadjuvant therapy regimens, is scarce.
OBJECTIVE:
This study aims to evaluate the diagnostic accuracy of endoscopy for predicting luminal complete response after neoadjuvant therapy and compare its performance between patients receiving neoadjuvant chemotherapy and neoadjuvant chemoradiotherapy.
DESIGN:
Retrospective cohort study.
SETTINGS:
The study was conducted at a teaching hospital.
PATIENTS:
A total of 349 locally advanced rectal cancer patients (223 neoadjuvant chemotherapy, 126 neoadjuvant chemoradiotherapy) who underwent neoadjuvant therapy and restaging endoscopy were included.
INTERVENTIONS:
Three reviewers assessed endoscopic images independently to determine the occurrence of endoscopic complete response.
MAIN OUTCOME MEASURES:
The diagnostic accuracy for predicting pathological luminal complete response (ypT0) was calculated.
RESULTS:
The overall accuracy of endoscopy for predicting complete response was 92.0% (321/349), with a positive predictive value of 69.6%, sensitivity of 69.6% and specificity of 95.4%. A flat scar was the most predictive feature (positive predictive value = 70.3%). The sensitivity of endoscopic performance was significantly higher in the neoadjuvant chemoradiotherapy group compared to the neoadjuvant chemotherapy group (90.0% vs. 53.8%,
LIMITATIONS:
No video or artificial intelligence was involved.
CONCLUSIONS:
Endoscopy is an optional tool for identifying luminal complete response after neoadjuvant therapy. Its sensitivity is lower after neoadjuvant chemotherapy than after neoadjuvant chemoradiotherapy, warranting caution against missed diagnoses. Beyond the flat scar, other features like small flat ulcers also have a non-negligible complete response rate. The role of routine biopsy still needs further exploration. See Video Abstract.