No, caffeine doesn't appear to cause breast cysts (fibrocystic breast changes), a noncancerous (benign) breast disease. There's also no evidence to suggest a link between caffeine and breast cancer. Although no research has documented this effect, it's OK to go caffeine-free to see.
There are several common causes of benign breast lumps: breast pain, especially birth control pills, hormone replacement therapy, soy products, and caffeine.
Speculation that caffeine may increase breast cancer risk followed reports that or who had greatly increased or decreased their coffee intake over the past