Microsatellite Instability Is a Favorable Prognostic Indicator in Patients With Colorectal Cancer Receiving Chemotherapy

Gastroenterology. 2000 Oct;119(4):921-8. doi: 10.1053/gast.2000.18161.

Abstract

Background & aims: Adjuvant 5-fluorouracil (5-FU)-based chemotherapy is standard treatment for stage C colorectal cancer (CRC). Approximately 12% of CRCs are characterized by microsatellite instability (MSI), a hallmark of a DNA mismatch repair defect. We investigated the safety of adjuvant 5-FU-based chemotherapy for MSI(+) CRC and compared the prognosis of MSI(+) and MSI(-) CRC patients receiving adjuvant therapy.

Methods: Previously, a prospective series consisting of 1044 consecutive CRCs has been collected and the MSI status of each sample determined. Patients with stage C cancer who had received adjuvant chemotherapy (n = 95) were followed up for 7-63 months (median, 31 months) after surgery.

Results: No unexpected or serious adverse effects were observed when 5-FU-based chemotherapy was used as adjuvant treatment for MSI(+) CRC. Three- year recurrence-free survival was 90% and 43% in the MSI(+) (n = 11) and MSI(-) (n = 84) groups, respectively (P = 0.020).

Conclusions: Adjuvant 5-FU-based chemotherapy is feasible for both MSI(+) and MSI(-) CRCs, and patients with MSI(+) CRC who receive adjuvant therapy have an excellent prognosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Base Pair Mismatch*
  • Chemotherapy, Adjuvant
  • Colonic Neoplasms / drug therapy
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / mortality
  • Colonic Neoplasms / pathology
  • Colonic Neoplasms / surgery
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / pathology
  • Colorectal Neoplasms / surgery
  • DNA Repair
  • Disease-Free Survival
  • Female
  • Fluorouracil / therapeutic use*
  • Follow-Up Studies
  • Humans
  • Male
  • Microsatellite Repeats*
  • Middle Aged
  • Neoplasm Staging
  • Prognosis
  • Rectal Neoplasms / drug therapy
  • Rectal Neoplasms / genetics
  • Rectal Neoplasms / mortality
  • Rectal Neoplasms / pathology
  • Rectal Neoplasms / surgery
  • Survival Rate

Substances

  • Fluorouracil