Family BC history and oral contraceptives for teens

I have a younger sister (she started oral contraceptives in her early teens) who was diagnosed with very aggressive BC at age 30 - large tumor, ER/PR-, poorly differentiated, lymph node involvement {but has responded well to chemo :)}.  We also have a maternal aunt dx with BC in her 50s (not aggressive).  
I have a 15 yr old daughter with menstrual cramps (sometimes severe), very irregular cycles in the last 6-9 months, and abdominal pain. It has been suggested that she be placed on an oral contraceptive to regulate, help with pain, etc., but I have been very reluctant in light of the family history of BC.  I have been told that the fact that my sister was dx at a young age makes it more likely to be hereditary.  What is the latest info regarding oral contraceptives being related to BC risk?

Thanks!!

[CCF-RN,MSN-rf]

Dear itsalwayssomething:  It is correct that women who are diagnosed young are more likely to have a hereditary form of breast cancer than those diagnosed earlier.  However, if she were to have genetic testing and were found to have the gene, she would also have a higher risk of ovarian cancer.  

Currently, there is little evidence to support the notion that birth control (BC) pills increase the chance of developing breast cancer very substantially.  One study, a large meta-analysis showed that risk was related more to total months of use and ultimately calculated to a relative risk of 1.38% for 10 years of use.  Also, the pills of the past contained far higher concentrations of estrogen and progestin than those used today.  Today's combination BC pills contain very low doses.  This fact makes analysis even more difficult because you cannot compare over time.  Most women have been on many different "pills," so it's very difficult to evaluate.  Finally, a study was recently published that indicates that BC pills, particularly those with higher doses of progestin, have actually been credited with reducing the incidence of ovarian cancer.

In your daughter's case, you should discuss the pro's and con's with her and her doctor, keeping in mind the severity of her symptoms, the relative risks, and expected duration of use.  Good luck in you decision.