Breast cancer surgery clinicians in California

Understanding CMS Data

CMS's "Mastectomy" category combines specific billing codes for breast surgery to calculate the number of times each clinician billed Medicare for a "Mastectomy." These include partial removal of the breast (lumpectomy); removal of the whole breast, with or without underarm lymph nodes; breast reconstruction after mastectomy; implant and implant-capsule procedures; breast lift and reduction; placement of a radiation device during surgery; and surgery for enlarged male breast tissue. CMS reports only procedures that clinicians billed to Original Medicare and Medicare Advantage. Therefore, CMS's procedure volume data does not include procedures that clinicians may have performed on patients who have other health care coverage (e.g., commercial insurance, self-pay, or the VA). Billing variation and coding errors can also affect CMS's data. Therefore, the number of procedures that CMS reports for a clinician may be higher or lower than the actual number of mastectomy procedures a clinician performed during the reporting period. Lastly, only clinicians with a primary specialty of General Surgery or Surgical Oncology (as reported to Medicare) are presented.

Source: Centers for Medicare & Medicaid Services (August 18, 2026 release).