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Observational Study
. 2022 Jul;36(7):4893-4902.
doi: 10.1007/s00464-021-08841-z. Epub 2021 Nov 1.

Sampling error in the diagnosis of colorectal cancer is associated with delay to surgery: a retrospective cohort study

Garrett G R J Johnson  1   2 , Olivia Hershorn  1 , Harminder Singh  3 , Jason Park  1 , Ramzi M Helewa  4
Affiliations
Observational Study

Sampling error in the diagnosis of colorectal cancer is associated with delay to surgery: a retrospective cohort study

Garrett G R J Johnson et al. Surg Endosc. 2022 Jul.

Abstract

Background: Accurate histopathologic diagnosis of colorectal cancer is important for treatment decision-making and timely care. The aim of this study was to measure rates and predictors of sampling errors for biopsy specimens attained at flexible lower gastrointestinal endoscopy, and to determine whether these events lead to a delay in surgical care.

Methods: This is a retrospective observational study of patients who underwent elective resection for colorectal adenocarcinoma between January 2007 and June 2020. Primary outcomes were proportion of incorrectly diagnosed colorectal adenocarcinomas at index endoscopy by histopathology, and time between endoscopy and surgery. Secondary outcomes were predictors of sampling error, and diagnostic yield of repeat endoscopy.

Results: Sampling errors occurred in 217/962 (22.6%) flexible endoscopies for colorectal adenocarcinomas. Negative biopsies were associated with a longer median time to surgery (87.6 days, IQR 48.8-180.0) compared to true positive biopsies (64.0 days, IQR 38.0-119.0), p < 0.001. Controlling for lesion location, neoadjuvant therapy, endoscopist specialty, year, and repeat endoscopies, time to surgery remained 1.40-fold longer (p < 0.001) following sampling error. Repeat endoscopy occurred following 62/217 (28.6%) cases of sampling errors, yielding a correct diagnosis of cancer in 38/62 (61.3%) cases. On multivariable analysis, sampling errors were less likely to occur for lesions endoscopists described as suspicious for malignancy (OR 0.12, 95% CI 0.07-0.21) or simple polyps (OR 0.24, 95% CI 0.08-0.70) compared to endoscopically unresectable polyps.

Conclusions: Colorectal cancers are frequently improperly sampled, which may lead to treatment delays for these patients. When cancer is suspected, surgeons should take care to ensure timely management.

Keywords: Biopsy; Colonoscopy; Colorectal cancer; Endoscopy.

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Conflict of interest statement

Garrett Johnson, Olivia Hershorn, Harminder Singh, Jason Park and Ramzi Helewa all indicate that they have no conflicts of interest or financial ties to disclose.

Figures

Fig. 1
Fig. 1
Flow chart of included/excluded patients of charts reviewed for retrospective cohort study of patients who underwent elective surgical resection for colorectal cancer at St. Boniface Hospital from January 2007-June 2020
Fig. 2
Fig. 2
Proportion of cancers improperly sampled at index endoscopy per year
Fig. 3
Fig. 3
Time (days) from index endoscopy to surgery stratified by sampling error
See this image and copyright information in PMC

References

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