According to a media release issued last Thursday, a paper presented at a cancer conference in Anaheim, California, last week suggests that men with prostate cancer who drank green tea every day day prior to having a radical prostatectomy had a significant reduction in markers for prostate inflammation.
The paper, by Henning and other researchers from the David Geffen School of Medicine at the University of California Los Angeles, gave results from a randomized study of the consumption of 6 cups of freshly brewed green tea or or 6 cups of water daily for 3 to 8 weeks, depending on the timing of their surgery.
The core results of the study, as reported in the media release from the American Association for Cancer Research, showed that, at the end of the study:
- Serum PSA levels were significantly lower compared with baseline levels in men consuming green tea.
- Expresssion of PSA in actual prostate tissue was lower in men assigned to green tea consumption compared with the control group.
- Expression of nuclear factor kappa B, a known marker of prostate inflammation, was significantly reduced in men assigned to green tea compared with the control group.
- An unspecified urinary marker of oxidative DNA damage was significantly decreased in urine from men assigned to green tea compared with the control group.
However, it also has to be noted that the researchers found:
- No differences in markers of tumor cell proliferation between the two treatment groups.
It has long been known that drinking green tea on a regular basis can have a variety of effects on the prostate in at least some men. However, there are no really meaningful data on whether drinking green tea can actually lower risk from prostate cancer in men who have not been diagnosed with this condition or whether it can reduce risk for prostate cancer progression in men diagnosed wioth low-risk prostate cancer who could theoretically be managed by active surveillance.
While the study reported in this media release does appear to offer some futher insights into the association between consumption of green tea and subsequent effects on markers for prostate inflammation, it does not tell us anything very significant about whether the effects on the markers are actually associated with clinical effects on the progression of prostate cancer. While drinking green tea is highly unlikely to to be harmful (even if you like drinking a lot of it), this study can not be used to justify the idea that men who have already been diagnosed with prostate cancer and then drink green tea will necessarily either (a) do better on long-term active surveillance or (b) do better after first-line therapy of any type.
The media release also does not give us enough information about the precise level of risk of the 67 participants in the study. We don’t know anything about their age, their baseline PSA levels, their clinical stages, their Gleason scores, or the volume of prostate cancer in their prostates. It would appear that they were all low-risk patients based on the language of the media release, but we cannot be certain since we haven’t seen the data from the actual presentation.