A new study led by Dr. Janet Stanford, published in Cancer Causes & Control, revealed that drinking coffee can prevent prostate cancer from recurring and progressing in some men. It's one of the first times researchers have made this connection, and the study is part of an emerging effort to pinpoint whether coffee and caffeine can reduce risk for a variety of cancers. Stanford sat down with Quest to discuss her team's findings - and what they mean for men wondering whether to pour themselves another cup.
Q: Is there a link between drinking coffee and developing prostate cancer?
A: This study didn’t look at the risk of developing prostate cancer. It took a large cohort of men who were previously diagnosed with prostate cancer and followed them to see whether their pattern of coffee or tea consumption – or both – related to their risk of having their prostate cancer relapse or progress.
We found that about 60 percent of men in the study consumed at least one cup of coffee per day, and 14 percent consumed four or more cups per day. The men who consumed at least one cup per day had a 56 percent reduced risk of prostate cancer recurrence or progression compared to men who consumed one or fewer cups per week. The effect was a bit stronger among men who drank four or more cups a day, who had a 59 percent lower risk of cancer recurrence.
Q: Does this mean prostate cancer survivors should be heavy coffee drinkers?
A: Not necessarily. In fact, we observed a significant decline in risk of recurrence in men who drank just one cup a day. So a man would not need to drink a large number of cups of coffee per day to benefit from its potential chemopreventive effects.
Q: How does tea consumption influence the risk of prostate cancer recurrence?
A: For tea consumption, we found no association with prostate cancer recurrence. Tea has a much lower level of caffeine than coffee, for one thing, and it also has different chemical components that do not overlap with those found in coffee.
Photo by Matt Hagen
Q: How do you explain coffee’s preventive effect on prostate cancer recurrence?
A: Caffeine and other chemical components of coffee have been shown to reduce cancer-cell proliferation and metastasis as well as enhance cancer-cell death. Also, some substances in coffee have anti-inflammatory and antioxidant effects, which would in theory be beneficial in terms of chemoprevention activity. There are also some compounds in coffee that may alter DNA methylation, a biochemical change that may influence cancer-associated genes. Thus, there are several potential biological mechanisms by which coffee might have health benefits for secondary prevention of prostate cancer.
Q: Were there any potential negative health effects among men who drank four or more cups of coffee per day, such as high blood pressure?
A: We couldn’t determine those types of associations in this study. One would need to carefully measure blood pressure, for example, before and after coffee consumption. However, coffee consumption for some men may not be recommended based on their medical history. Men with high cholesterol, high blood pressure or cardiac arrhythmias may be advised by their physicians not to consume excessive amounts of coffee.
Q: Have other studies shown a link between coffee and reduced risk of cancer recurrence?
A: Some studies of brain and ovarian cancer have found an association between coffee consumption and reduced risk of developing cancer, but few studies have evaluated coffee in relation to the cancer coming back or progressing. A recent large study from Harvard found a 60 percent reduction in the risk of developing metastatic or lethal prostate cancer associated with coffee consumption. So, the evidence is accumulating that there may be benefits from coffee drinking.
Q: Could drinking coffee prevent prostate cancer in the first place?
A: I don’t believe that there have been human trials of coffee as a primary preventive agent for prostate cancer. That would be something of interest, because the literature on coffee consumption related to risk of developing prostate cancer is mixed. Some studies have shown a beneficial effect and some, including one from our research group, have shown no association. But more and more we’re finding that factors involved in developing cancer are not necessarily involved in encouraging or preventing the cancer from recurring
Q: Based on your study, what would you tell men about coffee and prostate cancer?
A: Well, I think if a man has been diagnosed with prostate cancer and he’s a coffee drinker, then he should continue with his usual coffee consumption. A daily cup of coffee may offer some health benefits in terms of preventing or delaying prostate cancer recurrence or progression. More studies are clearly needed, but at this point I’d suggest that a small amount of coffee for most men is not going to be harmful and may provide some benefit.
Kristen Woodward, a science editor at Fred Hutchinson Cancer Research Center, has been in communications and media relations at Fred Hutch for more than 15 years. Before that, she was a managing editor at the University of Michigan Health System and a reporter/editor at The Holland Sentinel, a daily in western Michigan. She has received many national awards for health and science writing. She received her B.A. in journalism from Michigan State University. Reach her at firstname.lastname@example.org.