Accurate staging of non-metastatic colon cancer with CT: the importance of training and practice for experienced radiologists and analysis of incorrectly staged cases

S van de Weerd, E Hong, I van den Berg, J W Wijlemans, J van Vooren, M W Prins, F J Wessels, B C Heeres, S Roberti, J Nederend, J H J M van Krieken, J M L Roodhart, R G H Beets-Tan, J P Medema*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

PURPOSE: To investigate whether locoregional staging of colon cancer by experienced radiologists can be improved by training and feedback to minimize the risk of over-staging into the context of patient selection for neoadjuvant therapy and to identify potential pitfalls of CT staging by characterizing pathologic traits of tumors that remain challenging for radiologists.

METHODS: Forty-five cases of stage I-III colon cancer were included in this retrospective study. Five experienced radiologists evaluated the CTs; 5 baseline scans followed by 4 sequential batches of 10 scans. All radiologists were trained after baseline scoring and 2 radiologists received feedback. The learning curve, diagnostic performance, reader confidence, and reading time were evaluated with pathologic staging as reference. Pathology reports and H&E slides of challenging cases were reviewed to identify potential pitfalls.

RESULTS: Diagnostic performance in distinguishing T1-2 vs. T3-4 improved significantly after training and with increasing number of reviewed cases. Inaccurate staging was more frequently related to under-staging rather than over-staging. Risk of over-staging was minimized to 7% in batch 3-4. N-staging remained unreliable with an overall accuracy of 61%. Pathologic review identified two tumor characteristics causing under-staging for T-stage in 5/7 cases: (1) very limited invasive part beyond the muscularis propria and (2) mucinous composition of the invading part.

CONCLUSION: The high accuracy and specificity of T-staging reached in our study indicate that sufficient training and practice of experienced radiologists can ensure high validity for CT staging in colon cancer to safely use neoadjuvant therapy without significant risk of over-treatment, while N-staging remained unreliable.

Original languageEnglish
Pages (from-to)3375-3385
Number of pages11
JournalAbdominal Radiology
Volume47
Issue number10
Early online date7 Jul 2022
DOIs
Publication statusPublished - Oct 2022

Keywords

  • COMPUTED-TOMOGRAPHY
  • Colon cancer
  • Computed tomography
  • Learning curve
  • NEOADJUVANT CHEMOTHERAPY
  • Neoadjuvant therapy
  • PILOT PHASE
  • PREOPERATIVE T
  • Radiology

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