Proximal colon cancer in patients aged 51-60 years of age should be tested for microsatellites instability. A comment on the Revised Bethesda Guidelines.
Int J Colorectal Dis 2008;
23:801-6. [PMID:
18446350 DOI:
10.1007/s00384-008-0484-2]
[Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/02/2008] [Indexed: 02/04/2023]
Abstract
PURPOSE
The Bethesda guidelines suggest to perform microsatellite instability (MSI) test in early onset rectal cancer and not in patients>50 years with proximal colon cancer. The aim of the study was to evaluate whether the risk of high MSI (MSI-H) is greater in proximal colon cancer of patients 51-60 years old than in early-onset rectal cancer.
METHODS
Consecutive colorectal cancer (CRC) patients were evaluated. Tumor location, cancer family history, MSI status and histology were recorded. Mutations in MLH1/MSH2 were investigated in MSI-H tumors. Patients were subdivided into groups: group A, proximal colon cancer patients 51-60 years old and groups B, C and D, patients<or=50 years old, with rectal cancer, proximal and distal colon cancer, respectively.
RESULTS
Out of 409 CRC patients evaluated, 48 (12%) showed tumors with MSI-H. No MSI-H tumors were found in distal and rectal tumors of patients at sixth decade of life. Group A included 27 patients, eight (29.7%) MSI-H cancers, four missense mutations in MLH1/MSH2; groups B, C and D included 26, 11 and 11 patients with two (7.7%), two (18%) and two (18%) MSI-H cancers, respectively. One missense mutation on MSH2 in group B, one pathogenetic mutation on MSH1 in group C and one pathogenetic mutation on MSH2 in group D were found. Tumors of group A showed an increased probability to have MSI-H if compared to those of group B (OD=4.907, p=0.043).
CONCLUSIONS
The Bethesda criteria should be broadened to include patients 51-60 years old with proximal colon cancer.
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