Does microsatellite instability predict the efficacy of adjuvant chemotherapy in colorectal cancer? A systematic review with meta-analysis

Eur J Cancer. 2009 Jul;45(10):1890-6. doi: 10.1016/j.ejca.2009.04.018. Epub 2009 May 6.


Background: Microsatellite instability (MSI) status in predicting the efficacy of adjuvant chemotherapy in colorectal cancer remains controversial.

Materials and methods: Studies were identified through PubMed, Embase and ASCO proceedings with a combination of keywords (colorectal cancer, chemotherapy and MSI).

Results: A MA was performed for treated and non-treated MSI population on seven studies. Statistical calculations were performed on 7 studies representing 3690 patients; mean age: 65.5 years; 810 stage II and 2444 stage III (75%). MSI-high (MSI-H) was found in 454 patients (14% of the global population), and microsatellite stable (MSS) in 2871. A total of 1444 patients received 5-fluorouracil (5FU)-based chemotherapy, whereas 1518 patients did not. For MSI-H patients, there was no statistically significant difference for RFS whether or not they received chemotherapy (5 studies); HR RFS: 0.96 (95% confidence interval (CI): 0.62-1.49); HR OS (6 studies): 0.70 (95% CI: 0.44-1.09; p=0.12). Elsewhere, we found a significant interaction between MSI status (MSI-H or MSS) and therapeutic status suggesting a lesser benefit for MSI-H than for MSS patients (HR interaction RFS: 0.77 (95% CI: 0.67-0.87)).

Conclusion: We found similar RFS for treated and untreated MSI-H patients, showing that MSI-H status, in addition to being a good prognostic factor is also a predictive factor of non response.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Aged
  • Antineoplastic Agents / therapeutic use*
  • Chemotherapy, Adjuvant
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / genetics*
  • Colorectal Neoplasms / pathology
  • Female
  • Humans
  • Male
  • Microsatellite Instability*
  • Middle Aged
  • Neoplasm Staging
  • Prognosis
  • Survival Analysis
  • Treatment Outcome


  • Antineoplastic Agents