Japanese Clinical Trial Surprising Findings About Green Tea and Breast Cancer

The use of Green tea and its link to cancer prevention remains inconclusive. This post looks at the findings of one study in Japan conducted back in 2005.

Today we look at a clinical trial from Japan that answers an important Question:

What is the link between Green Tea and Breast Cancer ?

This paper specifically looks at the effect of Green tea on breast cancer. It is important to note that current evidence on this is inconclusive. This means that there is no solid proof that Green tea can help prevent cancer, however, most authors can’t really say there is no link because there are studies that show that there is an effect. So, in other words, the answer is: maybe. Although this study was done a few years ago, it’s interesting to look at what the authors found.

Paper: Influence of Drinking Green Tea on Breast Cancer Malignancy among Japanese Patients

Kei Nakachi  Kimito Suemasu  Kenji Suga  Takeshi Takeo  Kazue Imai  Yasuhiro Higashi

What was done?

The researchers looked at 472 patients with stages 1,2 and 3 cancer. They looked specifically at certain prognostic markers ( measurements that help them predict if the patient is improving or not). This data was then compared to the patient’s green tea consumption- so they noted if they drank green tea or not and if they did how many cups a day. The researchers continued to follow up on patients for a period of 7 years to see how their cancer progresses.

What did they find out?

One of the parameters they looked at was the spreading of breast cancer. Breast cancer lesions usually spread to the axilla (armpit). They found that in the earlier stages – stage and 1 and 2- women who consumed green tea had significantly less metastasis (spread).

Women who consumed green tea had less recurrence of stage 1 and 2 breast cancer lesions, according to the 7 year follow up findings.

However, for women in stage 3 breast cancer, green tea consumption had no effect on the outcome.

Did it matter how many cups a day? The authors found that the greatest risk reduction was among women who drank between 4 and 5 green tea cups a day.

So what?

As we mentioned before, the evidence that green tea can prevent cancer remains inconclusive. However, this study shows that green tea may have a preventive effect in the early stages. This study also supports the theory that green tea may help prevent the recurrence of breast cancer, although there is no definite link to date. Many studies conducted on animals have documented this effect, but studies on humans have not.


The role of green in preventing cancer remains inconclusive, however, this study hints at a preventive effect in the early stages of breast cancer.

Read more about the anti-oxidant effects of Green Tea.

Disclaimer: The above post is based on our views of already established research. The paper quoted above remains the property of its authors. The paper above is not the only one in the field our papers may report different findings so do not take our analysis as an all-encompassing opinion.  Instead, take it with a grain of salt. The opinions expressed here are in no way a replacement of an expert professional opinion.  Products displayed on the website are not related to the research papers cited.  The posted product links to other websites may include monetized affiliate links. 

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