Evaluations of vascular incasion, perineural invasion and serosal involvement in pathology slides of colorectal cancer

Colorectal cancer (CRC) is one important cause of mortality in the world. In the common staging systems of CRC, many biological behaviors of the tumor that determine the prognosis are not defined. Risk stratification is becoming increasingly important in low-stage CRC, because these patients do not undergo adjuvant therapy unless poor prognostic factors such as vascular invasion (VI), perineural invasion (PI) and serosal involvement (SI) are present. Accurate evaluation of these factors in CRC specimens is still challenging.

In this study, we evaluated the detection rate of VI, PI and SI in 180 patients of CRC who underwent surgical resection based on basic pathology reports, review of hematoxylin and eosin (H&E) slides with considering morphologic clues such as “protruding tongue” and “orphan artery” signs, and elastin stain for detection of VI. In addition, the stage of the disease, pT stage, tumor location, tumor type and grade were categorized, separately. We used the Fisher’s exact test for comparing variables between the two groups. P<0.05 was considered significant. All data analyzed using SPSS version 26.

Overall, the detection rate of VI was significantly increased in review of H&E slides with considering morphologic clues (P=0.019) and also using elastin stain (P<0.05) than basic pathology reports, but no significant differences observed in PI (P=0.118) and SI (P=1.00) between the first basic pathology reports and review of H&E slides. Also, significant differences observed in VI, PI and SI based on AJCC stage, pT stage and grade of tumor (P<0.05).

Considering the prognostic importance of VI detection in the treatment of patients of CRC, Slide review with attention to the morphologic clues such as “protruding tongue” and “orphan artery” signs and elastin staining could be used for better detection of VI in patients of CRC in routine surgical specimens.