Drinking coffee continues to be associated with improved outcomes in patients with colorectal cancer, although a cause-and-effect relationship remains unproven.
Previously, coffee-drinking patients with colorectal cancer classified as stage 3 — affecting lymph nodes but not spread to other organs — had been shown to have a lower risk of cancer recurrence and death than those who did not drink the beverage. But whether coffee consumption influenced outcomes in patients with advanced or metastatic disease — that which had spread beyond the colon to other organs — was not known.
Now, results of a large observational study have found that coffee consumption, especially four or more cups a day, was associated with a lower risk of the disease progressing and with longer survival, say researchers from Dana-Farber and other organizations. The new study is published in JAMA Oncology. Both caffeinated or decaffeinated coffee consumption appeared to be associated with improved outcomes.
“Although it is premature to recommend a high intake of coffee as potential treatment for colorectal cancer, our study suggests that drinking coffee is not harmful and may potentially be beneficial,” says Kimmie Ng, MD, MPH, senior author of the study. “Further research is needed to determine if there is indeed a casual connection between coffee consumption and improved outcomes in patients with colorectal cancer, and precisely which compounds within coffee are responsible for this benefit. This study adds to the large body of literature supporting the importance of diet and other modifiable factors in the outcomes of patients with colorectal cancer.”
Dana-Farber’s Chen Yuan, ScD, is co-first author of the report with Christopher Mackintosh, MLA, of the Mayo Clinic School of Medicine.
The study comprised 1,171 patients with advanced or metastatic colorectal cancer who participated in a phase III clinical trial comparing the addition of the drugs cetuximab and/or bevacizumab to standard chemotherapy in patient with previously untreated locally advanced or metastatic colorectal cancer. As part of the trial, the patients reported their dietary intake, including coffee consumption, on a questionnaire at the time of enrollment.
Patients who drank one cup of coffee per day had an 11% increased rate of overall survival and a 5% increased risk of living progression-free compared with people who did not drink coffee. Those who drank four or more cups a day had a 36% increased rate of overall survival and a 22 percent increased rate of surviving without their disease getting worse. The median follow-up time among living patients was 5.4 years. A total of 1,092 patients (93%) had died or had disease progression.
The mechanism of coffee’s effects on colorectal cancer outcomes isn’t known. However, several compounds found in coffee have antioxidant, anti-inflammatory, and insulin-sensitizing effects, which may contribute to anticancer activity, note the researchers.