The purpose of this study is to look for ways to improve breast cancer treatment by giving breast cancer drugs through the skin of the breast.

The drug used in this study is a diclofenac epolamine patch and is a nonsteroid anti-inflammatory pain reliever. The drug amount that gathers in the breast, after application of a patch to the skin of the breast, will be measured and compared to the amount that is found in the breast when the patch is applied to the skin of the belly.

This is a randomized study where participants in group 1 will apply the diclofenac epolamine patch to the breast and participants in group 2 will apply the same drug to her abdomen. Participants are instructed to apply a new patch every 12 hours for 3 days. Total participation in this study will be for three days, ending on the day of surgery. On the day of surgery, participants will have blood drawn to measure the level of diclofenac epolamine in the body, and the final patch will be removed.

Inclusion Criteria:

• Women between the ages of 18 and 80 years, undergoing total mastectomy for, with or without axillary surgery for diagnosis or prevention of breast cancer.
• ECOG performance status less than 2.
• Ability to understand and the willingness to sign a written informed consent.
• Participants must have normal organ and marrow function

Exclusion Criteria:

• Prior history of ipsilateral breast radiotherapy.
• Pregnant women and those who will be actively breast-feeding in the preoperative period will be excluded.
• Inability to discontinue aspirin or warfarin use during the period of participation.
• Known allergy to diclofenac epolamine, or aspirin, diclofenac (Cataflam, Voltaren), or another non-steroidal anti-inflammatory drug (NSAID).
• Renal failure