On bisphosphonate b4 diagnosis DCIS??

coykoi

My mom started taking bisphosphonates ~ 1-2 yrs ago to prevent bone loss (osteoporosis), after she broke her wrist. Then recently she was diagnosed with DCIS (which has since become invasive, but that's a different story).

Now, I have been reading that a study has shown that bisphosphonates INCREASE the risk of DCIS... while decreasing the risk of invasive breast cancer occurrence. The study authors explain this by saying that bisphosphonates slow down the cancer development, so more is getting caught at the in situ stage.

But an alternative explanation has to be, could bisphosphonates CAUSE DCIS?? It's still weird to me that my mom would get breast cancer, with no family history whatsoever, though of course that does happen.

So, I'm just curious whether any of you guys were on bisphosphonates before being diagnosed with DCIS.

Link for anyone interested: 

http://www.breastcancer.org/risk/new_research/20100622b.jsp

cycle-path

I've been on bisphosphonates since 2005, mostly IV rather than oral. I was also on estrogen-only HRT since 2001. Diagnosed with DCIS December 2010. 

I think DCIS can happen to anyone, family history or not. My mother's sister had BC, but no one else in the (very large and long-lived) family. It's just a very common cancer.