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Combination of Microsatellite Instability and Lymphocytic Infiltrate as a Prognostic Indicator in Colon Cancer
Eugene Y. Chang, MD;
Paul B. Dorsey, MS;
Joseph Frankhouse, MD;
Randall G. Lee, MD;
Deb Walts, MSN;
William Johnson, MD;
George Anadiotis, DO;
Nathalie Johnson, MD
Arch Surg. 2009;144(6):511-515.
Background Microsatellite instability (MSI) is a genetic aberration associated with less aggressive tumor biology. Some tumors with MSI also have lymphocytic infiltrate (LI), which suggests a heightened immune response against the tumor.
Objective To evaluate the combined prognostic significance of MSI and LI in a colon cancer population.
Design Colon cancers were prospectively evaluated for MSI by assessing 11 satellite markers and were classified as MSI+ if 2 or more satellite markers displayed instability. Tumors were classified as LI+ if at least 5 lymphocytes were observed per 10 high-power fields.
Setting Community hospital system.
Patients Individuals undergoing definitive surgery for colon cancer.
Main Outcome Measures Overall and disease-free survival were compared according to combined MSI and LI status.
Results In 150 patients, tumors were classified as follows: 95 were MSI–/LI–, 9 were MSI–/LI+, 30 were MSI+/LI–, and 16 were MSI+/LI+. Median follow-up was 40.6 months. Five-year disease-free survival was 56.7% for patients with MSI–/LI– tumors and 88.9% for those with MSI+/LI+ tumors (P = .01). Patients with MSI+/LI– and MSI–/LI+ tumors had 5-year survival of 75.4% and 75.0%, respectively.
Conclusions Patients with colon cancer and MSI–/LI– tumors have worse disease-free survival rate regardless of stage at diagnosis. Patients exhibiting both MSI+ and LI+ tumors have more favorable disease-free survival rates. Both MSI and LI show promise as a combined prognostic marker and with further study may prove to be particularly useful in selecting patients with stage II disease for adjunctive therapy.
Author Affiliations: Oregon Health and Science University, Department of Surgery (Dr Chang), and Legacy Health System (Drs Frankhouse, Lee, W. Johnson, Anadiotis, and N. Johnson, Mr Dorsey, and Ms Walts), Portland.
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Combination of Microsatellite Instability and Lymphocytic Infiltrate as a Prognostic Indicator for Adjuvant Therapy in Colon Cancer
Kumar et al.
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