Relationship between Microsatellite Status and Other Prognostic Factors in Patients with Colon Cancer

It is reported that 0.5-13 % of all colorectal cancers are hereditary. Many mutations that cause genomic instability have been described lately in this cancers; the most famous one is yet microsatellite instability pathway. Investigating the presence of these mutations is important in tailoring patients' treatment and predicting prognosis.

Aims: We evaluated the association between micro satellite status and other pathologic prognostic factors like grade, tumor size, lymph node metastasis, lymphovascular invasion and perineural invasion in patients who underwent curative colon resection for colorectal cancers (CRC) in our clinic in the past five years.

Study Design: A total of 205 sequential patients who were older than 18 and had curative colon resection for CRC in Ankara University Surgical Oncology Unit and been tested for microsatellite instability (MSI) were analyzed on behalf of the facultys’ database.

Methodology: Pathology results had been determined and tumor localizations, lymph node metastasis status, grade, lymphovascular and perineural invasion status were evaluated. Information about MSI status and defected genes were obtained from detailed pathology reports. Patients were divided into two groups as MSI and MSS.

Results: No significant difference was found between two the groups in the context of microsatellite instability status. Lymphovascular invasion had been seen higher in high frequency microsatellite instability (MSH-H) compared to low frequency microsatellite instability (MSH-L) group (76.4% vs 53.1%, P =.02). There was no statistical difference in perineural invasion between the two groups (P = 0.102). Signet ring cell status between the groups we found a higher rate of signet ring cells and consequently a higher grade in MSH-H group (17.6% vs 10.6%, P = 0.042).

Conclusion: In conclusion, although many important points have been identified in our study, more studies are needed to compare the evaluation of MSI in colon cancer with other prognostic factors and to investigate its effect on the course of the disease.