If i choose breast-sparing surgery, how much of my breast has to be taken if cancer?

Depend: It will depend on how big is the mass and the size of your breast. The surgery is aimed to remove all breast cancer tissue and make sure that the margins are negative-free from cancer involvement. If the mass is too large for your breast size, a mastectomy would be recommended instead of a lumpectomy. Please discuss further with your surgeon. Good luck.

Cancer&a little more: The 'art' of lumpectomy is to remove enough to prevent recurrence but not so much that the cosmetic results are poor. Factors include the size and location of the ca & the breast size. Using modern oncoplastic techniques, most women are very satisfied with the outcome. Please address these issues with your surgeon pre-op.

"clear" margins: The total volume of removed tissue depends on the size of the tumor (larger tumor=larger excision). The surgical treatment of the cancer requires it be removed with "clear" margins. How much of a margin is needed is debated (mm's vs "no tumor on ink"). Once this is accomplished, then one needs to assess what's left. If the cosmetic outcome is unacceptable then a mastectomy is usually preferred.

Tumor size matters: This question is best answered by a surgeon who is able to evaluate you in person. The amount of tissue that needs to be removed depends on the size of the tumor and your breast size. If you have a larger tumor, then getting chemotherapy before surgery can shrink the tumor so less breast tissue needs to be removed. Seek out a good surgeon and even get a 2nd opinion to evaluate options.

Depends on size: The surgeon must achieve "clean" margins so the amount of breast tissue removed depends on the size and location of the tumor and the extent of spread into the breast. This should be discussed with the surgeon before surgery. Also, because of your age it is crucial to have brca genetic testing before deciding on lumpectomy!