Metformin and Breast Cancer

imbell

Metformin and Breast Cancer

imbell

An inexpensive drug that's already used to treat type 2 diabetes could find new life as a cancer fighter, with two new studies suggesting it can fight off colon cancer and even prevent lung cancer in smokers.

The drug is called metformin, and is sold as Glucophage. It's widely used by type 2 diabetics who overproduce insulin. But new research conducted at the National Cancer Institute in the U.S. has found that metformin can also fight lung cancer tumour growth in mice that have been exposed to a common carcinogen in cigarettes.

Metformin has been previously shown to activate an enzyme that is known to inhibit a protein that regulates cell growth and survival in tobacco-induced lung tumours.

For this study, NCI researchers, led by Dr. Philip Dennis, gave the mice metformin either orally or by injection. Those treated orally had between 40 and 50 per cent fewer tumours, while those mice treated with injection had 72 per cent fewer tumours.

A second study, also to be published in the journal Cancer Prevention Research, suggested metformin may prevent colorectal cancer tumours in humans by targetting the earliest stages of the disease.

What excites researchers is that unlike chemotherapy and radiation, which burn and poison cancer cells, metformin's effects are more subtle.

It's thought the drug works by targeting a cancer tumour's stem cells which, if not killed off, can allow various cancer cell types to regenerate.

"It's not killing them; it is actually suppressing their growth and without growth, the cells eventually die," explains Vuk Stambolic, a cancer researcher at Princess Margaret Hospital in Toronto.

Metformin was originally designed for diabetics who overproduce insulin. It works by preventing the liver from breaking down starch into sugar while also stimulating uptake of sugar by the body's muscles, causing blood sugar and insulin levels to fall.

But when a number of studies noticed that diabetic patients taking metformin also had a significantly lower cancer rate, scientists began investigating its cancer-fighting properties.

Dr. Michael Pollak, a professor of oncology at McGill University, said the findings that metformin might be a cancer fighter are "one of the most unexpected and innovative findings" he's seen in years.

"Here we have an old molecule, an old drug, a safe drug that may have an unexpected use in cancer prevention and cancer treatment. The findings represent an unexpected and exciting lead," he said.

These are not the first studies to note metformin's ability to fight cancer.

A study released last year found that combining metformin with the chemotherapy drug doxorubicin reduced breast cancer tumours faster than doxorubicin alone, when tested on mice. The drug combo also prolonged remission in the mice longer than chemotherapy alone.

Dr. Pamela Goodwin, a medical oncologist at Mount Sinai Hospital in Toronto has three studies underway investigating if metformin can slow or prevent breast cancer in 3,500 women.

She notes that it's been tough getting funding for her studies because metformin is "an orphan drug," a generic drug not backed by any pharmaceutical company. And with no patent, there is no financial incentive for drug companies to fund research.

"We first proposed this five years ago," she told CTV News. "It took us five years of multiple presentations and requests for funding to cobble together funding."

She notes that metformin is a generally safe medication with a long history.

"It's important to develop this as quickly as we can, because if it is beneficial, we need to get this out to patients," she says.

hrf

I was alerted to the clinical trial here in Toronto. Fortunately or unfortunately, I was dx with type 2 diabetes a few months ago (probably a result of the chemo according to my doc) and I've been taking metformin since then. I do hope it can do double duty.

LuvRVing

As a type 2 diabetic, I have been taking Metformin (Glucophage) for 9 years, and still managed to get breast cancer.  I'm hoping that it prevents a recurrence.  And it might explain the necrosis that encapsulated the IDC that I did have (which in my case was a good thing).  I'm following this research closely.

Michelle

Anonymous

That Dr. Pamela Goodwin researcher has been spot on in the past with her Vitmin D research and breast cancer.

When she gets a passion to investigate something it seems to have real promise. Also, she is a very conservative researcher. She never says anything until she has a lot of evidence.

Husband11

There is evidence that BC patients on glucophage during chemo have significantly higher rates of total response.  Good to hear that research is continuing.  I noticed a while back an interesting parallel between metformin and maitake extract.  Both have in common the ability to increase insulin response and are being investigate for breast cancer treatment.  Lets hope for a succesful treatment.

CrunchyPoodleMama

I had Googled "Metformin and breast cancer" a few months ago because my infertility specialist wanted to put me on it (I'm not diabetic but one of my insulin resistance tests was on the "high end of normal"), and I wanted to make sure it didn't increase cancer risk. I was heartened to find that it seems to lower the risk... needless to say I have been on it for the last three months. I'm glad they're now doing more detailed studies of this relationship. 

BTW, cinnamon is supposedly a natural substance that has a similar effect on insulin resistance that metformin has. I wonder if cinnamon would also have a similar cancer-fighting effect?

Packer5

Metformin is also given to women as an infertility treatment. My daughter became pregnant after taking metformin (in conjunction with the customary home remedy).

Laughjoyfully

Yes Yes Yes I have ben studying this for a year -  and here it is - I am sooo excited -  I have an Ebook about how to use it -  the theory behind it is not really as clear as this but it is all there -  I just wanted to wait until I saw some research before I went ahead .. Thank You for posting this

Linda

CrunchyPoodleMama

Linda, what is the ebook?

Packer5, I'm glad it helped your daughter conceive... hoping it helps my husband and me conceive a healthy baby! (We're really "trying" this month for the first time since my DCIS diagnosis a year ago!)

BaseballFan

Anyone have anything to add about metformin?

momoschki

My integrative oncologist from Cornell in NYC has prescribed this for me-- I have been on it since last March.  No BC dx in my case, but ADH, which puts me at higher risk.  He is convinced that it has preventive value-- let's hope so!  No SE's whatsoever, btw.

Kaara

There is a great article in this month's edition of "Life Extension" magazine about the benefits of Metformin and it's ability to slash cancer risk.   The article states that there have been trials done with diabetics and the results have been astounding with regard to the reduction of cancers.  In 8,000 diabetics over a 10 year period the drug slashed the risk of all cancers by 54%.  Although talked about and in the planning stages, no trials have been conducted thus far on non diabetics; however, it was Life Extension's contention that you should not wait, and should talk to your doctor about a metformin regimen at a dose of 250-500 mg twice a day.

To quote the article, Metformin operates at the molecular level by activating AMPK, a molecule essential to life.  When AMPK is activated, incipient cancer cells starve themselves to death for lack of adequate energy supplies. 

sweetbean

I read a study that said that exercise counteracted the effects of Metformin.  Any thoughts on that?

AlaskaAngel

Trial info:

http://community.breastcancer.org/forum/73/topic/765092

geewhiz

Oh GEEZ Sweetbean!! I hooe not! I am on metformin and exercise hard regularly. I wonder why?

LuvRVing

Clinical trials information for breast cancer and metformin:

http://www.clinicaltrials.gov/ct2/results?term=breast+cancer+and+metformin

This one relates to metformin and breast cancer recurrence:

http://www.clinicaltrials.gov/ct2/show/NCT01101438?term=breast+cancer+and+metformin&rank=6

This is the study that sweetbean is talking about.  It is based on a reaction by diabetics to metformin's ability to lower glucose, and they found that it worked better on non-exercise days.  I don't think that necessarily applies to its anti-cancer-fighting abilities.

http://www.sciencedaily.com/releases/2011/08/110819131523.htm

sweetbean

Interesting.  Isn't the anti-cancer fighting ability related to its ability to lower glucose, though?

geewhiz

Thanks for the links!

I have read lots about this since I am on it off-label. They are not entirely sure how it's working but it seems to be more complex than just glucose levels being lowered. I have seen it discussed that it is perhaps changing enzyme pathways somehow. Regardleas, I will stay on it and keep exercising. i keep firing so many arrows, hopefully something will work!!

Kaara

I am going to ask my integrative physician to prescribe this for me.  I would rather take this than one of the other anti hormone treatments that are currently being recommended by my onc.  The logic seems to fit with my anti cancer diet which is removing as much starch and sugar as possible on the assumption that cancer feeds and receives it's energy from glucose.  There are no reported SE's according to the article.

painterly

A friend of mine who takes Metformin for diabetes told me that she has extreme fatigue from the drug. Perhaps that is because she is diabetic?

sweetbean

I knew another woman who had pretty strong side effects from Metformin.  I'm really interested in it, but I get nervous because of what I have read.  Maybe I will bring it up with my integrative doctors.  I'm sure my onc won't know anything about it.

Kaara

I'm going to look into the side effects of metformin...the article I read said there were little or none, compared to chemotherapy or radiation.  It did issue a word of caution that the drug should not be taken by people who had type 1 diabetes, those who have had heart attack or stroke, or those who had any kind of liver damage as it could cause a potentially life threatening problem.

rosemary-b

What I wonder is if it can cause hypogycemia in people with normal blood sugar levels.

sweetbean

I think the key phrase here is "compared with chemotherapy and radiation."  Pretty much all SE's are mild compared to losing all your hair, etc.  But still, the stats are very encouraging.  What I really want to do is go to Chicago to visit the Block Center and find out what they have to say about it.

geewhiz

No side effects whatsoever with me...

sweetbean

What is interesting about the study is that it seems to say that the subjects were not measured after regular daily exercise, but rather, after a single bout of exercise.  So the exercise may have counteracted the effects of the Metformin because the body doesn't want glucose levels to dip too low AND the body was basically being introduced to two glucose-lowering stratagies at the same time.  Perhaps the results would be different for people who exercise regularly and whose bodies have already adjusted to the impacts of exercise.  Someone should study THAT!

LuvRVing

I've been taking 2000 mg of metformin since June 2010 and I have no side effects.

momoschki

To echo what several others have already said, I take 500 mg twice a day and have absolutely NO side effects at all.

thats-life-

Hi kaara/sweetbean/all...My family doc has said he will prescribe metformin to me if i want it. So now just have to make the decision. I was wondering too what effects it could have on someone who isnt diabetic. but he seemed to be implying it was quite harmless.

I am also wondering what dosage to take. Is there a standard dosage for the BC clinical trials? and does that differ from the standard dosage for a diabetic?

At stage IV, Im thinking its worth a try 

thanks for any info, n.

Kaara

thats-life:  Life Extension recommends starting on 250-500 mg per day.  I know I have read on the site here that there are women take larger doses, but I would imagine your doctor will know what dose is best to begin.  I am going to talk to my doctor about this as well.