LAS VEGAS – The use of Mohs surgery in Medicare beneficiaries increased steeply in the past decade, mainly for nonmelanoma skin cancers on the face and with great variation in treatment practices, two new studies show.
The majority of physicians who billed Medicare for Mohs surgeries do relatively few of the procedures per year, raising questions about the optimal volume of Mohs surgeries to ensure good outcomes and cost-effectiveness, one of the studies suggested.
Dr. Matthew Donaldson
The United States is experiencing an epidemic of nonmelanoma skin cancer, which has grown in numbers from approximately 1 million in 1994 to approximately 4 million per year today, Dr. Matthew Donaldson said at the annual meeting of the American College of Mohs Surgery.
The rate of Mohs surgery per 1,000 Medicare beneficiaries increased by 236% between 1999 and 2009, while excisions and destructions of lesions increased by approximately 20%, said Dr. Donaldson, who is training in Mohs surgery under Dr. Brett Coldiron at the skin cancer center of TriHealth Good Samaritan Hospital, Cincinnati.
He and his associates analyzed the Medicare claims database for 2009 to examine who is doing Mohs surgery, and why. They utilized both the Physician/Supplier Procedure Summary Master File (which contains data on all claims for procedures) and a random sample of 5% of claims called the Medicare Limited Data Set Standard Analytic File.
For CPT code 17311 (Mohs surgery on the head, neck, hands, feet, genitalia, or any location directly involving muscles, cartilage, bone, tendon, major nerves, or vessels), Florida and Arizona had more than twice the rate of claims, compared with the national average of 14 claims per 1,000 Medicare beneficiaries.
For CPT code 17313 (Mohs surgery on the trunk, arms or legs), Florida and Arizona had three times the national average of two claims per 1,000 Medicare beneficiaries.
Only 0.1% of CPT 17311 claims and 0.4% of CPT 17313 claims were for malignant melanoma. Carcinoma in situ made up 1% of CPT 17311 claims and 2% of CPT 17313 claims. The rest were for malignant neoplasms, "predominantly for basal cell and squamous cell" carcinomas, he said.
Of the 1,777 medical providers who billed for Mohs surgery in 2009, 97% were dermatologists, accounting for approximately 18% of all practicing dermatologists in the United States.
Dr. Donaldson and his associates used the data to estimate how many Mohs cases each claimant performed. Approximately 44% of physicians who billed Medicare for Mohs surgery did fewer than 200 cases that year, approximately 35% did 300-1,000 cases, and only 5% did more than 1,000 cases, he predicted.
"A full 27% of surgeons in the country are doing, on average, 47 cases in Medicare" beneficiaries, "and probably 100 cases overall for the entire year," Dr. Donaldson said. "Is that a sufficient number to really maximize" cure rates, cosmetic outcomes, and cost-effectiveness?
The physicians who did large volumes of Mohs surgeries in Medicare beneficiaries were more likely to take additional stages beyond the initial surgery, and were more likely to repair defects themselves, compared with low-volume surgeons, he said.
Dr. Kate V. Viola reported in a separate presentation that a minority of nonmelanoma skin cancers in the Medicare population is treated with Mohs, but the use of Mohs for these cancers is increasing at a much faster rate than the use of excisions.
She and her associates looked at a 5% sample of Medicare claims from 2001-2006 in the SEER (Surveillance, Epidemiology and End Results) database representing 26% of the U.S. population in 16 registries.
Of the 26,931 Medicare beneficiaries who were treated for nonmelanoma skin cancers, 36% were treated with Mohs surgery and 64% were treated with wide local excision or simple excision.
The rate of Mohs surgery for nonmelanoma skin cancer "doubled – yes, doubled – by 2006," increasing from 0.7 per 100 beneficiaries in 2001 to 1.5 per 100 beneficiaries, said Dr. Viola of Albert Einstein College of Medicine, New York. During that period, the rate of excisions for nonmelanoma skin cancers increased only slightly, from 1.8 to 2.1 per 100 beneficiaries.
Mohs surgery was more likely than excisional surgery on the face and less likely elsewhere. Mohs surgery was used to treat 47% of facial lesions and 15% of lesions on the rest of the body, she said.
Patient age, race, and geographic region were significantly associated with the likelihood of Mohs surgery. The use of Mohs for these cancers decreased with patient age (from 41% of patients aged 67-69 years to 34% of patients 85 years or older). Mohs was used in 37% of white patients, 23% of black patients, and 29% of patients of other races.