Abstract
The conventional histologic grading of colorectal cancer (CRC) is less suited for resected rectal cancer following neoadjuvant chemoradiation. Enumeration of poorly differentiated clusters (PDC) is a recently proposed histologic grading scheme. We aimed to apply PDC grading to treated rectal cancer and to test the prognostic significance of this novel approach. Archived hematoxylin and eosin slides of 72 rectal adenocarcinomas resected following neoadjuvant treatment were retrieved. PDC, tumor budding, and tumor regression were assessed. The parameters were correlated with clinicopathological features and survival. PDC was strongly associated with tumor budding, perineural invasion (PNI), metastasis, and low degree of tumor regression. Tumor budding was significantly associated with lymphovascular invasion and PNI, and metastasis. Tumors with a lower degree of regression were more likely to show high pathologic T stage and advanced clinical stage. Local recurrence was associated with poor survival. PDC did not correlate with overall survival. PDC grading is applicable to resected rectal cancer status post neoadjuvant treatment and correlates with established histopathological prognosticators. PDC and tumor budding may represent a histologic spectrum reflective of the same biological significance. Validation and incorporation of these simple histologic grading schemes may strengthen the prognostic power of the histologic parameters that influence the oncologic outcome in treated rectal cancer. Further study to evaluate the significance of PDC as an oncologic prognosticator is warranted.
Highlights
The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) classification and staging system based on tumor, node, and metastasis (TNM) is widely used to predict clinical outcome and guide therapeutic management in colorectal cancer (CRC) [1]
Clinical management considers additional histologic features such as tumor grade, lymphovascular invasion (LVI) and perineural invasion (PNI), nodal micrometastasis, and tumor budding as adjunctive prognosticators to further stratify patients with CRC [2,3,4,5,6]
We aimed to determine whether poorly differentiated clusters (PDC) is applicable to treated rectal cancer, and whether it is associated with other clinicopathological variables including tumor budding, tumor regression, and survival
Summary
The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) classification and staging system based on tumor, node, and metastasis (TNM) is widely used to predict clinical outcome and guide therapeutic management in colorectal cancer (CRC) [1]. Clinical management considers additional histologic features such as tumor grade, lymphovascular invasion (LVI) and perineural invasion (PNI), nodal micrometastasis, and tumor budding as adjunctive prognosticators to further stratify patients with CRC [2,3,4,5,6]. The histologic grading scheme is subject to high interobserver variability [2]. The grading scheme loses its prognostic power in some histologic subtypes of CRC, such as mucinous, medullary, and micropapillary carcinomas [8], thereby limiting its utility. The accurate assessment of the other morphologic factors that significantly influence prognosis—LVI, nodal micrometastasis, and tumor budding—often necessitate immunohistochemical workup or multilevel sectioning, requiring additional resources and limiting their utility in routine clinical practice [10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
