title: A novel histologic grading scheme based on poorly differentiated clusters is applicable to treated rectal cancer and is associated with established histopathological prognosticators.
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.
authors.affiliation: Department of Pathology, University of Vermont, Burlington, Vermont.
authors.forename: Michelle
authors.initials: M
authors.lastname: Yang
authors.affiliation: Anatomic Pathology, Albany Medical College, Albany, New York.
authors.forename: Aseeb Ur
authors.initials: AU
authors.lastname: Rehman
authors.affiliation: Anatomic Pathology, Albany Medical College, Albany, New York.
authors.forename: Chunlai
authors.initials: C
authors.lastname: Zuo
authors.affiliation: Anatomic Pathology, Albany Medical College, Albany, New York.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Sheehan
authors.affiliation: Department of Surgery, Albany Medical Center, Albany, New York.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Lee
authors.affiliation: Pathology and Laboratory Medicine, Indiana University, Indianapolis, Indiana.
authors.forename: Jingmei
authors.initials: J
authors.lastname: Lin
authors.affiliation: Pathology and Laboratory Medicine, Indiana University, Indianapolis, Indiana.
authors.forename: Zijin
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Pathology and Laboratory Medicine, Indiana University, Indianapolis, Indiana.
authors.forename: Euna
authors.initials: E
authors.lastname: Choi
authors.affiliation: Anatomic Pathology, Albany Medical College, Albany, New York.
authors.forename: Hwajeong
authors.initials: H
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D000066491:Clinical Decision-Making; D019468:Disease Management; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000401:mortality* / Q000601:surgery
chemical_list: D015415:Biomarkers
keywords: Histologic grading; poorly differentiated clusters; rectal cancer; tumor budding; tumor regression