Saturday, September 11, 2010

Metformin and Breast Cancer

As a diabetic who has taken metformin since 2001, I am very interested in following the results of these particular clinical trials. 

Because my hormone receptors are "barely positive" and this protocol is being used for hormone negative prevention, I am even more interested.

There are other clinical trials that show a benefit of pairing metformin with or without traditional chemotherapy in a neoadjuvant setting (which means chemo before lumpectomy or mastectomy).  In many cases, the tumors are shrinking away completely.

This is the current Canadian clinical trial, which involves administering metformin for a few weeks prior to surgery (without traditional chemo):

Metformin works to reduce the amount of insulin circulating in the body and helps the cells to be more receptive to the insulin required to maintain glucose control.  I have read studies that indicate sugar feeds cancer, and too much insulin also feeds cancer cells.

So the fact that metformin would work to prevent cancer makes some sense.  Remember that almost half my tumor had "died" prior to surgery.  Well, we had doubled  my metformin right at my cancer diagnosis because my numbers were running too high.  It makes me wonder if the metformin did double duty.   There's no way to be sure, unfortunately.  But I'll be on this drug probably forever.  And unless the clinical trials prove otherwise, I'm hoping that the anti-cancer properties work for me.  I think they already did some good work!


  1. The metformin link is very interesting. I was thinking of going off the met because of my last A1C. Now I'm thinking, there's probably more good to just continue taking it.


  2. Interesting. I had started a thread on WebMD about this, but it went sort of sideways with the usual conspiracy theory stuff about big pharma. Sorry I didn't think of it for you at the time (brain fart!) but I did hear that it was being given to women with breast cancer. Talk about a good treatment with minimal side effects.


  3. That's OK, Cora. I had already heard about it and had asked my onco the first time I saw him. He didn't think much of the idea; but now that there's a Canadian trial offering Metformin as a post-cancer treatment rather than an anti-hormone, I don't see how anyone can dismiss the idea. I am almost convinced that it was doing a number on my tumor and helped to shrink it before surgery.

  4. Wow, Michelle, that is really interesting. Since my doctor wanted me to stay on Met because of the evidence that it delays the progression of DM, I am following her advice. Seems now that there may be another good reason to stay with it.


  5. Wow...makes me "want" to take Metformin!