Can Green Tea Help Treat Cancer?

Can Green Tea Help Treat Cancer?
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A mixture of results have been reported using green tea to try to stop or reverse the progression of oral cancer, lung cancer, cervical cancer, and colon cancer.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Tea consumption may reduce the risk of getting oral cancer. Not only may the consumption of tea boost the antioxidant power of our bloodstream within minutes of consumption, and decrease the amount of free radical DNA damage throughout our systems over time, it can also increase the antioxidant power of our saliva, and decrease the DNA damage within the inner cheek cells of smokers—though not as much as stopping smoking altogether.

So, might this help precancerous oral lesions from turning into cancerous oral lesions? “More than [100,000] people develop oral cancer annually worldwide,” [with a] 5-year overall survival rate of less than” the flip of a coin. “Oral cancer frequently arises from” precancerous lesions in the mouth, with each have a few percent chance every year of turning cancerous. So, what a perfect opportunity to see if green tea can help.

“Fifty-nine…patients” with precancerous oral lesions were randomized into a tea group, in which capsules of powdered tea extract were given, as well as having the lesions painted with the green tea powder, versus a control group that essentially got sugar pills, and were painted with nothing. Within six months, lesions in 11 of the 29 in the tea group shrunk, compared to only 3 out of 30 in the placebo group. “The results indicate that tea treatment can improve the clinical manifestations of the oral lesions.”

The important question, though, is, did it prevent them from turning cancerous? But, because the trial only lasted a few months, they couldn’t tell. But, when they scraped some cells off of the lesions, there was a significant drop in DNA-damaged cells within three months in the treatment group—suggesting that things were going in the right direction. Ideally, though, we’d do a longer study, to see if they ended up with less cancer. And, while we’re at it, how about a study where they just used swallowed tea components, since most people don’t fingerpaint with tea in their mouths. We didn’t have such a study, though—until, we did.

Same extraordinary clinical results, with some precancerous lesions shrinking away. And, the study lasted long enough to see if fewer people actually got cancer. But, there was just as much new cancer in the green tea group as the placebo group. So, a higher response rate—I mean, the lesions looked better—but “no improvement in…cancer-free survival,” which is the whole point.

Now, these studies were done mostly on smokers and former smokers. What about lung cancer? Population studies suggest tea may be protective, but, let’s put it to the test.  Seventeen patients with advanced lung cancer given up to the equivalent of 30 cups of green tea a day, but “[n]o objective responses were seen.” Another study of 49 cancer patients—21 with lung cancer—who got between 4 and 25 cups worth of green tea compounds a day, and again, no benefits were found. The only benefit green tea may be able to offer lung cancer patients is to help lessen the burns from the radiation treatments when applied on the skin, as green tea compresses may be able to shorten the duration of the burns.

The protective effects of green tea applied topically were also seen in precancerous cervical lesions, where the twice-a-day direct application of a green tea ointment showed a beneficial response in nearly three-quarters of the patients, compared to only about a 10% response in the untreated control group, which is consistent with the anticancer effects of green tea compounds on cervical cancer cells in a petri dish. But, when women just got green tea extract pills to take, the pills didn’t seem to help.

I’ve talked about the potential benefit of green tea wraps for skin cancer. Is there any other cancer where green tea actually comes in direct contact? Yes, colon cancer, which grows from the inner surface of the colon that comes in contact with food and drink. In the colon, tea compounds are fermented by our good gut bacteria into compounds like 3,4DHPA, which appears to wipe out colon cancer cells, while leaving normal colon cells relatively intact in vitro.

So, 136 patients with a history of polyps were randomized to get green tea extract pills, or not. Now, this was a study in Japan; so, everyone was already drinking green tea. So, effectively, this was comparing those who drank three cups a day to four cups a day. But, a year later on colonoscopy, the added green tea group had only half the polyp recurrence, and the polyps that did grow were 25% smaller. That’s pretty exciting. Why hasn’t a larger follow-up study been done since? Perhaps due to the difficulty in raising funds for the study, because green tea is a cheap beverage, not a pharmaceutical.

But, the good news is that, thanks to a major cancer charity in Germany, researchers are currently recruiting for the largest green tea cancer trial to date, in which more than 2,000 patients will be randomized. I look forward to presenting the results when they come in.

Please consider volunteering to help out on the site.

Image credit: Samout3 via flickr. Image has been modified.

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Tea consumption may reduce the risk of getting oral cancer. Not only may the consumption of tea boost the antioxidant power of our bloodstream within minutes of consumption, and decrease the amount of free radical DNA damage throughout our systems over time, it can also increase the antioxidant power of our saliva, and decrease the DNA damage within the inner cheek cells of smokers—though not as much as stopping smoking altogether.

So, might this help precancerous oral lesions from turning into cancerous oral lesions? “More than [100,000] people develop oral cancer annually worldwide,” [with a] 5-year overall survival rate of less than” the flip of a coin. “Oral cancer frequently arises from” precancerous lesions in the mouth, with each have a few percent chance every year of turning cancerous. So, what a perfect opportunity to see if green tea can help.

“Fifty-nine…patients” with precancerous oral lesions were randomized into a tea group, in which capsules of powdered tea extract were given, as well as having the lesions painted with the green tea powder, versus a control group that essentially got sugar pills, and were painted with nothing. Within six months, lesions in 11 of the 29 in the tea group shrunk, compared to only 3 out of 30 in the placebo group. “The results indicate that tea treatment can improve the clinical manifestations of the oral lesions.”

The important question, though, is, did it prevent them from turning cancerous? But, because the trial only lasted a few months, they couldn’t tell. But, when they scraped some cells off of the lesions, there was a significant drop in DNA-damaged cells within three months in the treatment group—suggesting that things were going in the right direction. Ideally, though, we’d do a longer study, to see if they ended up with less cancer. And, while we’re at it, how about a study where they just used swallowed tea components, since most people don’t fingerpaint with tea in their mouths. We didn’t have such a study, though—until, we did.

Same extraordinary clinical results, with some precancerous lesions shrinking away. And, the study lasted long enough to see if fewer people actually got cancer. But, there was just as much new cancer in the green tea group as the placebo group. So, a higher response rate—I mean, the lesions looked better—but “no improvement in…cancer-free survival,” which is the whole point.

Now, these studies were done mostly on smokers and former smokers. What about lung cancer? Population studies suggest tea may be protective, but, let’s put it to the test.  Seventeen patients with advanced lung cancer given up to the equivalent of 30 cups of green tea a day, but “[n]o objective responses were seen.” Another study of 49 cancer patients—21 with lung cancer—who got between 4 and 25 cups worth of green tea compounds a day, and again, no benefits were found. The only benefit green tea may be able to offer lung cancer patients is to help lessen the burns from the radiation treatments when applied on the skin, as green tea compresses may be able to shorten the duration of the burns.

The protective effects of green tea applied topically were also seen in precancerous cervical lesions, where the twice-a-day direct application of a green tea ointment showed a beneficial response in nearly three-quarters of the patients, compared to only about a 10% response in the untreated control group, which is consistent with the anticancer effects of green tea compounds on cervical cancer cells in a petri dish. But, when women just got green tea extract pills to take, the pills didn’t seem to help.

I’ve talked about the potential benefit of green tea wraps for skin cancer. Is there any other cancer where green tea actually comes in direct contact? Yes, colon cancer, which grows from the inner surface of the colon that comes in contact with food and drink. In the colon, tea compounds are fermented by our good gut bacteria into compounds like 3,4DHPA, which appears to wipe out colon cancer cells, while leaving normal colon cells relatively intact in vitro.

So, 136 patients with a history of polyps were randomized to get green tea extract pills, or not. Now, this was a study in Japan; so, everyone was already drinking green tea. So, effectively, this was comparing those who drank three cups a day to four cups a day. But, a year later on colonoscopy, the added green tea group had only half the polyp recurrence, and the polyps that did grow were 25% smaller. That’s pretty exciting. Why hasn’t a larger follow-up study been done since? Perhaps due to the difficulty in raising funds for the study, because green tea is a cheap beverage, not a pharmaceutical.

But, the good news is that, thanks to a major cancer charity in Germany, researchers are currently recruiting for the largest green tea cancer trial to date, in which more than 2,000 patients will be randomized. I look forward to presenting the results when they come in.

Please consider volunteering to help out on the site.

Image credit: Samout3 via flickr. Image has been modified.

Doctor's Note

What about green tea and preventing cancer in the first place? That was the subject of my video Can Green Tea Help Prevent Cancer?.

And prostate cancer? See Preventing Prostate Cancer with Green Tea and Treating Prostate Cancer with Green Tea for more.

Here’s the older video I referenced regarding skin cancer: Treating Gorlin Syndrome with Green Tea.

For all our videos on the latest research on green tea, visit our Green Tea topic page.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

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