In spite of preliminary information suggesting that green tea may have some tumor fighting potential, in a new study green tea not only had no effect on prostate cancer but even caused some serious side effects.
The study is published in the March issue of Cancer.
Prostate cancer is the most common cancer in men and the second leading cause of cancer deaths in men after lung cancer. A previous survey found that more than 25% of men with prostate cancer tried alternative treatments.
In the current study, Aminah Jatoi, MD, and colleagues tested the effects of a highly concentrated form of green tea. The researchers measured PSA (prostate specific antigen) blood levels over the four-month course of the study in 42 men with prostate cancer -- falling PSA levels usually indicate a good response to treatment.
Each man -- who had previously failed prostate cancer treatment with hormone therapy -- was given six doses of green tea to drink during the day. The amount of caffeine in the tea equaled approximately two-and-a-half cups of coffee.
The results were disappointing. Researchers were hoping for at least a 5% decline in PSA levels. However, only one man had any response to green tea -- and the response only lasted two months. Overall, PSA levels continued to rise throughout the study.
The researchers also saw quite a few side effects from green tea. Almost 70% of men experienced symptoms ranging from nausea to vomiting, insomnia, fatigue, diarrhea, confusion and abdominal pain. Some of the side effects were severe, even leading to hospitalization for one man with confusion.
The researchers say approaches other than green tea should be explored for prostate cancer treatment.