This study aims to assess whether gabapentin should be a standard component of peri-operative pain control in mastectomy patients at Memorial Sloan Kettering Cancer Center.

Inclusion Criteria:

• Age 18 to 65 years
• Undergoing ambulatory extended recover (AXR) mastectomy (bilateral or unilateral) at the Josie Robertson Surgical Center (JSRC)

Exclusion Criteria:

• None

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.