Interobserver Variability in Assessing Pathologic Response to Preoperative Treatment in Rectal Cancer: Standardization of an Evaluation Method and Comparisons Between Published Scales
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Evaluating tumor response of rectal cancer to preoperative chemoradiotherapy (NCRT) has a prognostic value on overall survival; however, grading tumor response is a controversial issue due to lack of reproducibility and the lack of information about the standardization of the evaluation.
We performed this study to examine the variability between observers’ assessment of the pathological responses to NCRT using a systematic quantitative grading system based on a percentage of tumor response against the proportion of residual tumor burden. As a secondary aim, we classified the tumor response according to six published systems to determine the correlation between the observers into each grading system.
From 70 cases, the mean age was 60.6 ± 11.78 years, 36 (51.47%) patients were female, the pathological T stage was pT3 in 48.6% of cases, pT2 in 32.9%, pT1 in 11.4% and 7.1% in pT4, whereas 40% had lymph node metastasis. The median lymph node count was ten lymph nodes (range 6–43). Our method of tumor regression evaluation has a good intraclass correlation (ICC) value. From the scales compared regarding interobserver agreement, the Ryan’s and Royal College of Pathologists showed fair agreement (but good ICC); the scales from Dworak, Becker, and Rizk showed substantial agreement (and good to excellent ICC values); and the scale from Rödel showed almost-perfect agreement.
All the evaluated systems showed good interobserver agreement, but the best interobserver agreement was reached with the Rödel’s scale.
KeywordsRectal cancer Interobserver agreement Tumor response Scales Chemoradiotherapy
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflicts of interest.
Declaration of Authorship
All authors meet the criteria for authorship as per the guidelines of the International Committee of Medical Journal Editors (ICMJE), all have participated at (1) conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND (2) drafting the work or revising it critically for important intellectual content; AND (3) final approval of the version submitted; AND (4) agreement to be accountable for all aspects of the work regarding the accuracy or integrity of the research.
Conception and Design
Leonardo S. Lino-Silva.
Provision of Study Materials or Patients
Collection and Assembly of Data
Leonardo S. Lino-Silva, Cristina J Guzmán-López.
Data Analysis (Statistical Analysis) and Interpretation
Leonardo S. Lino-Silva, Rosa A. Salcedo-Hernández.
Final Revision and Approval of Manuscript
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