In a large group of patients with metastatic colorectal cancer, consumption of a few cups of coffee a day was associated with longer survival and a lower risk of the cancer worsening, according to a study led by researchers at Dana-Farber Cancer Institute. The findings, reported in the paper, 'Association of Coffee Intake With Survival in Patients With Advanced or Metastatic Colorectal Cancer', published JAMA Oncology, based on data from a large observational study nested in a clinical trial, are in line with earlier studies showing a connection between regular coffee consumption and improved outcomes in patients with non-metastatic colorectal cancer.
"It's known that several compounds in coffee have antioxidant, anti-inflammatory, and other properties that may be active against cancer," explained Dana-Farber's, Dr Chen Yuan, the co-first author of the study with Dr Christopher Mackintosh of the Mayo Clinic School of Medicine. "Epidemiological studies have found that higher coffee intake was associated with improved survival in patients with stage 3 colon cancer, but the relationship between coffee consumption and survival in patients with metastatic forms of the disease hasn't been known."
It is known that several compounds found in coffee possess antioxidant, anti-inflammatory and insulin-sensitizing effects, which may contribute to anticancer activity. Previous epidemiological studies have reported possible associations between increased coffee consumption and decreased recurrence and mortality of colorectal cancer. However, the association between coffee consumption and survival in patients with advanced or metastatic colorectal cancer is unknown.
Subsequently, researchers at Dana-Farber Cancer Institute sought to evaluate the association of coffee consumption with disease progression and death in patients with advanced or metastatic colorectal cancer. The prospective, observational, cohort study involved 1,171 patients with previously untreated locally advanced or metastatic colorectal cancer who were enrolled in Cancer and Leukemia Group B (Alliance)/SWOG 80405, a completed phase 3 clinical trial comparing the addition of cetuximab and/or bevacizumab to standard chemotherapy. Patients reported dietary intake using a semiquantitative food frequency questionnaire at the time of enrolment and the data were collected from October 2005 to January 2018. The primary outcome measure was overall survival and progression-free survival.
From 1,171 patients, a total of 1092 patients (93%) died or had disease progression. Increased consumption of coffee was associated with decreased risk of cancer progression (p=0.04 for trend) and death (p=0.004 for trend). Participants who consumed two to three cups of coffee per day had a multivariable hazard ratio for overall survival of 0.82 and for progression-free survival of 0.82, compared with those who did not drink coffee. Participants who consumed at least four cups of coffee per day had a multivariable hazard ratio for overall survival of 0.64 and for progression-free survival of 0.78. Significant associations were noted for both caffeinated and decaffeinated coffee.
The findings enabled investigators to establish an association, but not a cause-and-effect relationship, between coffee drinking and reduced risk of cancer progression and death among study participants. As a result, the study does not provide sufficient grounds for recommending, at this point, that people with advanced or metastatic colorectal cancer start drinking coffee on a daily basis or increase their consumption of the drink, the researchers noted.
"Although it is premature to recommend a high intake of coffee as a potential treatment for colorectal cancer, our study suggests that drinking coffee is not harmful and may potentially be beneficial," added Dana-Farber's, Dr Kimmie Ng, senior author of the study. "This study adds to the large body of literature supporting the importance of diet and other modifiable factors in the treatment of patients with colorectal cancer. Further research is needed to determine if there is indeed a causal connection between coffee consumption and improved outcomes in patients with colorectal cancer, and precisely which compounds within coffee are responsible for this benefit."