Addition of irinotecan may improve outcome for certain stage III colon cancer patients

Irinotecan-based therapy has recently been demonstrated to offer a survival benefit in a certain subset of patients with stage III colon cancer. This finding is the result of a new study, recently published in Gastroenterology.

Researchers led by Stacey Shiovitz of the University of Washington (WA, USA) investigated data gathered over 8 years from patients with stage III colon cancer. Half of these individuals were randomly assigned to receive fluorouracil and leucovorin, the current standard of care in this patient population. The remaining patients were treated with the standard fluorouracil and leucovorin, augmented with adjuvant irinotecan therapy.

Analysis revealed that patients with disease associated with the CpG island methylator phenotype (CIMP) had a significant increase in survival when irinotecan was added to their treatment. Patients with the CIMP, which is observed in approximately 10–20% of colorectal cancers, who received the additional treatment had an overall survival of 69%, compared with 56% in those who received standard chemotherapy.

However, in patients with CIMP-negative disease who received therapy with the addition of irinotecan, a significant decrease in overall survival was noted (68% compared with 78% for standard treatment alone).

“Our results serve as an example that the molecular characterization of individual tumors may help to determine the most appropriate treatment for patients with colon cancer,” commented Shiovitz, (University of Washington). “Based on our findings, identification of a tumor’s CIMP status should play a greater role in the clinical setting.”

Further studies are required to investigate these findings in a larger patient population and to further the understanding of the CIMP in the disease.

Source: American Gastroenterological Association press release