Published in Oncology
News · January 19, 2017
PracticeUpdate Editorial Team
January 18, 2017—San Francisco—Long-chain omega-3 fatty acids and dark-meat fish have been shown to improve disease-free survival in patients with colon cancer, with an 80% improvement in patients with tumors exhibiting high cyclooxygenase-2 (COX2) expression.
This finding of a prospective, federally funded cohort study utilizing data from the Alliance for Clinical Trials in Oncology, Cancer and Leukemia Group B will be reported at the 2017 Gastrointestinal Cancers Symposium, from January 19 – 21.
Erin L. Van Blarigan, ScD, of the University of California, San Francisco, explained that
long-chain omega-3 fatty acids may prevent colon cancer progression, but data in humans are lacking.
Dr. Van Blarigan and colleagues hypothesized that long-chain omega-3 fatty acids and dark-meat fish intake after colon cancer diagnosis would be associated with longer disease-free survival, particularly among patients whose tumors expressed COX2.
A total of 1011 patients with stage 3 colon cancer were enrolled in an adjuvant chemotherapy trial from 1999 – 2001. Intake of dark-meat fish; canned tuna; breaded fish; shrimp, lobster, scallops, clams; other fish; and fish oil supplements was assessed via a food frequency questionnaire during and 6 months after therapy. Fewer than 5% of patients reported taking fish oil supplements.
Hazard ratios and 95% confidence intervals for disease- and recurrence-free survival, as well as overall survival, were estimated, adjusting for clinical, sociodemographic, and lifestyle factors. In a subset of 510 patients, the investigators determined whether tumor COX2 expression modified the association between long-chain omega-3 fatty acid intake and disease-free survival.
A total of 343 colon cancer recurrences and 305 deaths (7 years median follow-up) were observed. Higher long-chain omega-3 fatty acid intake after colon cancer diagnosis was associated with 28% improved disease-free survival [hazard ratio for highest vs lowest quartile 0.72 (0.54, 0.97); P = .03].
The association was driven by reduced risk of colon cancer recurrence [hazard ratio for recurrence-free survival for the highest vs lowest quartile 0.68 (0.50, 0.94); P = .01; hazard ratio for overall survival for the highest vs lowest quartile 0.79 (0.56, 1.13); P = .17].
Among patients with tumors that had moderate to high expression of COX2, long-chain omega-3 fatty acid intake was associated with 80% improved disease-free survival [hazard ratio for the highest vs lowest quartile 0.2 (0.06 – 0.76); P = .006].
When dietary sources of long-chain omega-3 fatty acids were examined, patients who consumed dark-meat fish more than three times per month vs none experienced longer disease-free survival [hazard ratio 0.65 (0.48, 0.87); P = .007); recurrence-free survival [hazard ratio 0.63 (0.46, 0.86); P = .007], and overall survival [hazard ratio 0.68 (0.48, 0.96); P = .04]. No other fish or seafood was associated with disease- or recurrence-free survival or overall survival.
No other fish or seafood was associated with disease- or relapse-free survival or overall survival.
Dr. Van Blarigan concluded that long-chain omega-3 fatty acids and dark-meat fish intake may improve disease-free survival in colon cancer, especially among patients with tumors of high COX2 expression.
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