The Cost-Effectiveness of Mohs Micrographic Surgery Versus Surgical Excision in Basal Cell Carcinoma

Purpose: Of the 1.3 million cases of nonmelanoma skin cancers (NMSCs) expected to occur within a year in the United States, 80% will be basal cell carcinoma (BCC).(1) These cases affect primarily the elderly population translating into Medicare spending of $1.5 billion per year for the treatment of NMSCs.(2) Mohs micrographic surgery (MMS) has been advocated as the gold standard for treating NMSCs due to its advantages in lowering the recurrence rate of BCC from 2-5% with surgical excision (SE) to 1-2%(3) and in preserving tissue cosmesis.(4) Previous studies have suggested MMS to be cost-effective compared to SE, but have methodological shortcomings including questionable assumptions regarding recurrence rates of SE, consideration of only anatomical areas (i.e, the “H” zone of the face) known to have high predilection for recurrence, and neglecting closure and future reconstructive costs.(4) BCC has a metastasis rate of less than 1% and recurrence rate for microscopic incomplete excisions less than 35%.(5) Given this background and the serious issues confronting healthcare financing in the United States, we conducted a rigorous cost-effectiveness study of MMS versus SE that may contribute to a more robust analysis of the economic implications of the medical management of BCC.

Methods: In the absence of prospective trials on the relative outcomes of MMS versus SE for BCC, we created a decision tree model that utilized the probability of recurrence from the dermatologic and plastic surgery literature and costs from the American Medical Association 2008 Current Procedural Terminology (CPT) codes. The CPT codes were converted into dollar amounts using the Connecticut Medicare reimbursement rates for 2008 in the non-facility setting.

Results: The cost of MMS (CPT codes 17312, 17313) reflected Connecticut data revealing that MMS required a second stage 67% of the time, but omitted closure costs that may have required flaps. To evaluate MMS in a fair manner, the costs of MMS were minimized and the costs of SE were maximized. Thus, the cost of SE assumed tissue rearrangement (CPT code 14040) and permanent section (CPT code 88305), although many BCC lesions require a less expensive, smaller excision followed by simple layered closure. If recurrence occurred, it was assumed that MMS required only one stage and that SE required another tissue rearrangement and frozen section (CPT code 88331). Using a recurrence rate of 1% for MMS and 5% for SE, the total cost that accounted for reexcision of recurrent lesions was $1,320 per patient for MMS and $854 per patient for SE. This implies an incremental cost-effectiveness ratio (ICER) of $11,634, indicating that a single percent of recurrence avoided by MMS costs over $10,000.

Conclusions: This study reveals a major cost differential of $465 million in the treatment of BCC between MMS and SE on a national annual basis. Given the current economic climate and concerns over healthcare funding, it suggests that further study of the risk of recurrence, impact on quality of life, and economic costs of treatment for this common cancer are warranted.

References: 1. Alam, M., Ratner, D. Cutaneous squamous-cell carcinoma. N Engl J Med 344: 975-983, 2001. 2. Bickers, D. R., Lim, H. W., Margolis, D., et al. The burden of skin diseases: 2004 a joint project of the American Academy of Dermatology Association and the Society for Investigative Dermatology. J Am Acad Dermatol 55: 490-500, 2006. 3. Bialy, T. L., Whalen, J., Veledar, E., et al. Mohs micrographic surgery vs traditional surgical excision: a cost comparison analysis. Arch Dermatol 140: 736-742, 2004. 4. Neville, J. A., Welch, E., Leffell, D. J. Management of nonmelanoma skin cancer in 2007. Nat Clin Pract Oncol 4: 462-469, 2007. 5. Pascal, R. R., Hobby, L. W., Lattes, R., et al. Prognosis of "incompletely excised" versus "completely excised" basal cell carcinoma. Plast Reconstr Surg 41: 328-332, 1968.