Poorly differentiated colorectal cancers: correlation of microsatellite instability with clinicopathologic features and survival

Am J Clin Pathol. 2013 Sep;140(3):341-7. doi: 10.1309/AJCP8P2DYNKGRBVI.


Objectives: To evaluate the association of microsatellite instability (MSI) with clinicopathologic features and oncologic outcomes in patients with poorly differentiated colorectal cancer (PD).

Methods: Study patients were divided into well-differentiated colorectal cancer (WD) and PD, which were compared according to histologic differentiation and MSI status.

Results: Among 1,941 patients, PD was more frequent among microsatellite-unstable tumors (23.6%) than among microsatellite-stable (MSS) tumors (4.2%, P < .001). Patients with PD had worse 4-year overall survival rates than patients with WD (78.6% vs 88.2%, P = 0.010). Compared with MSS-PD tumors, MSI-PD tumors were characterized by right-colon predilection, larger size, and infrequent lymph node metastasis (P < .001 to P = .007).

Conclusions: The clinicopathologic characteristics of PD were closely associated with those of MSI. The outcomes of MSI-PD tumors were better than those of MSS-PD tumors, but this finding did not reach statistical significance.

Keywords: Colorectal adenocarcinoma; Microsatellite instability; Prognosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cell Differentiation / genetics*
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / pathology*
  • Female
  • Humans
  • Male
  • Microsatellite Instability*
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Survival Rate