Other, less serious potential side effects include fatigue, diarrhea, headache, loss of appetite, decreased white blood cell count, and mouth sores. And remember, potential side effects are just that: potential. Many women take Avastin without suffering any side effects at all.

Another troubling "side effect" is cost: Avastin costs upwards of $100,000 a year. And since it's not FDA-approved for breast cancer treatment, insurance companies cover it (or don't) on a case-by-case basis. Unless you have $100,000 extra in your family budget to spend on drugs, BE SURE you contact your insurance company before taking Avastin, to see if they'll cover the cost.

For more on the high cost of Avastin to treat women with metastatic breast cancer, read:

Avastin: Extending Life... Growing Stock Price? 

Note: Prior to its recent approval by the FDA in women with advanced breast cancer, Avastin had also been prescribed on an off-label basis to slow the progression of tumors in women with advanced (metastatic) breast cancer. When given with Taxol in clinical trials, it doubled the time (from about 5 1/2 months to about 11 months) that tumors didn't grow-although it didn't significantly prolong the women's lives.