Interobserver variability amongst gastrointestinal pathologists in assessing prognostic parameters of malignant colorectal polyps: a cause for concern

Diagnostic accuracy of high-resolution MRI as a method to predict potentially safe endoscopic and surgical planes in patients with early rectal cancer

“…The emerging consensus is that rather than using a method with poor inter-observer agreement, absolute measures of depth and width are more reliable and therefore prognostically more secure. 20 It has also been shown that depth and width of mucosal invasion predict the lymph node metastasis in ERC. 21 …”

Significant polyps and early colorectal cancer: the importance of high‐quality standardized histopathology

“…Poor differentiation is a recognized adverse prognostic feature; however, this is highly subjective. Some studies have shown poor agreement (kappa = 0.07) between even experienced gastrointestinal pathologists . A two‐tier classification is recommended in the UK with any poorly differentiated focus defining poor differentiation, and all other tumours being classed as well/moderately differentiated.…”

“…Even then, variability in the thickness of the submucosa and ulceration/destruction of the muscularis mucosae often make it difficult to assess submucosal thirds accurately. Agreement in Haggitt and Kikuchi staging has been shown to be ‘poor’ and ‘fair’, respectively, with kappa values of 0.15 and 0.36 between four experienced gastrointestinal pathologists . In Japan, the absolute depth of invasion beyond the muscularis mucosae has been shown to be predictive of nodal disease .…”

“…Both are now required to be reported under TNM8 along with perineural invasion. All three methods of spread can be difficult to report in practice, with only fair agreement (kappa 0.35) for lymphovascular invasion between experienced gastrointestinal pathologists . Lymphatic invasion can be overcalled in cases with retraction artefact and can also be easily missed.…”

SPECC and SPECULATION

“…The second important point we would make is that since the entire exercise relies on the histopathological diagnosis, the same pathologist is required to report on 'validated' prognostic parameters. We have just published an audit [4] and have shown, unfortunately, that experienced gastrointestinal histopathologists are not in unison in reporting prognostic parameters. We have shown in this paper that the recognition of width of invasion is not very good, thus confirming the findings of the Oxford group [5].…”