Mohs Micrographic Surgery (MMS) is a highly precise technique that removes skin cancer layer by layer, with immediate microscopic examination until all cancerous tissue is cleared, maximizing cancer removal while preserving healthy tissue. This method leads to high cure rates and smaller scars. When skin cancer requires this specialized treatment, beneficiaries need to understand how Medicare covers the procedure and the associated financial responsibilities.
Original Medicare Coverage Determination
Mohs surgery is generally covered by Original Medicare because it is considered a medically necessary treatment for skin cancer. Since the procedure is usually performed in an outpatient setting, such as a dermatologist’s office or an ambulatory surgical center, coverage falls under Medicare Part B. Part B covers medical services and supplies needed to diagnose or treat a medical condition. Coverage is provided when a physician determines Mohs surgery is the most appropriate course of treatment, including the surgical removal, microscopic examination, and necessary wound reconstruction.
Criteria for Medical Necessity
Medicare coverage for Mohs surgery is conditional upon meeting specific medical necessity criteria. The procedure is typically reserved for tumors located in areas where tissue preservation is a high priority, such as the face, eyelids, nose, lips, ears, hands, feet, and genitalia. These locations are considered high-risk due to their complex anatomy and cosmetic importance.
Medical necessity is also determined by the tumor’s characteristics, regardless of location. This includes high-risk basal cell carcinoma and squamous cell carcinoma that show aggressive growth patterns, poorly defined borders, or a history of recurrence. Large, deeply infiltrating tumors or those exhibiting specific aggressive histological features also support the need for Mohs surgery precision. Thorough documentation from the referring physician and the Mohs surgeon is required to justify the procedure to Medicare, detailing the lesion’s size, location, number of stages, and pathology findings.
Beneficiary Cost Sharing and Financial Responsibility
Even with coverage under Original Medicare Part B, the beneficiary retains financial responsibilities. The patient must first meet the annual Part B deductible before Medicare pays its portion of the costs. After the deductible is met, Medicare Part B pays 80% of the Medicare-approved amount for the Mohs procedure.
The patient is responsible for the remaining 20% coinsurance of the Medicare-approved amount, which varies based on the complexity and number of stages required to clear the cancer. For patients with a Medigap (Medicare Supplement Insurance) plan, the 20% coinsurance is often fully or partially covered by the supplemental policy. Patients must ensure their Mohs surgeon accepts Medicare assignment to avoid higher out-of-pocket costs.
Medicare Advantage Plan Differences
Medicare Advantage (Part C) plans must cover all medically necessary services that Original Medicare covers, including Mohs surgery. However, the way a patient accesses and pays for the service can differ significantly, often using fixed co-payments for surgical procedures instead of the 20% coinsurance model.
Many Medicare Advantage plans, particularly Health Maintenance Organizations (HMOs) or Preferred Provider Organizations (PPOs), require patients to use in-network providers. Using an out-of-network Mohs surgeon may result in higher costs or no coverage for non-emergency procedures. Unlike Original Medicare, most Medicare Advantage plans require prior authorization for Mohs surgery before scheduling. Failure to obtain this approval could lead to a denial of coverage or increased patient costs.