You should tell your friend (if she's willing to listen to advice) that breast implants are placed below the muscle in most cases, especially when breast lift is done, and they never increase nor decrease the risk of breast cancer. This includes those women who start at increased risk because of family history or precancerous biopsy, such as this case.
The question that needs to be addressed is: what happens to your lift plus implants in the event you eventually develop breast cancer? The answer is that all of the surgical and oncologic options remain, though such things as radiation therapy may increase risks of capsular contracture around your implants.
However, having this elective surgery now does not decrease your ability to undergo appropriate surgical and oncologic options should you develop breast cancer. Obtaining a soft, natural result is critical in allowing proper breast examination and mammographic evaluation, but capsular contracture does not increase your cancer risks, and may impact your ability to detect early lumps.
This scenario requires detailed discussion with the ABPS-certified plastic surgeon involved in this case, who likely has the general surgical training prior to plastic and reconstructive surgery training that allows him/her to knowledgeably discuss this specific situation. Best wishes! Dr. Tholen