A re-look at the modified Ryan regression scoring system in esophageal cancer-validation of prognostic significance and comparison with other less commonly used systems

Abstract

Background: Neoadjuvant chemoradiotherapy (NACRT) using CROSS protocol is currently the treatment of choice for esophageal cancer (EC). Tumor response grade (TRG) is a mandatory reporting criterion in most guidelines. One of the most commonly used TRG systems is the modified Ryan system. We aim to assess the TRG using modified Ryan and seven other systems (Mandard, Chireac, Swisher, Japanese esophageal society guidelines, modified rectal cancer regression grading (mRCRG), CROSS, and Becker) to evaluate their reproducibility and role as a prognostic marker.

Materials and methods: Two pathologists independently reviewed all cases of post-NACRT (CROSS) EC, to score TRGs and other histological parameters. Inter-rater agreement assessment for different TRG systems and correlation with disease-free survival (DFS) was performed.

Results: Our series includes 93 patients with predominantly mid-esophageal squamous cell carcinoma. Complete pathological response (pCR) was noted in 47% (44/93) patients. The kappa inter-rater agreement score for the Ryan system was substantial (0.774), while it was almost perfect agreement for tumor percentage assessment-based systems (Swisher, CROSS, and Becker). Only the mRCRG TRGs correlated significantly with prognosis, while the Ryan system did not. Tumor stage and pCR status did not correlate with DFS, though the nodal stage was clinically significant.

Conclusion: Though the inter-rater concordance was optimal for all the TRG systems studied, only the mRCRG system showed prognostic significance, while the commonly used modified Ryan system did not. It may be worthwhile to look at further evaluating other systems like mRCRG for inclusion in minimum dataset reporting.