A small number of Mohs surgeons are conducting more than three times the number of procedures as their colleagues.

Annual caseload data from 2016-2018 shows the Australasian College of Dermatologists (ACD) Mohs group mean was close to 300 cases per year. Yet a few clinicians were performing close to 1,000 cases per year.

“Carrying out more than 700 cases per year (two standard deviations above mean) indicates outlier status and should prompt a review of practice using the current guidelines and peer discussion,” said Perth dermatologist Dr Harvey Ronald Smith in a brief report published in the Australasian Journal of Dermatology.

The research also highlighted that for every additional Mohs case performed, the complexity of location decreased by 0.9%.

One of the benchmarks of quality for ACD Approved Mohs Micrographic Surgeons is that ‘90% of Mohs cases are carried out in difficult sites including the head and neck, lower leg, hands, digits or anogenital area’.

Yet the data showed ‘the more cases a surgeon performs, the lower the proportion that are in complex locations’.

Dr Smith told the limbic while there was always going to be some variation in practice, there were concerns the procedure was not being appropriately used.

“I think what the data shows is that the vast majority of us are practicing along those benchmark lines. It could be that the people who are outside of that have a very different population they are dealing with or maybe they just need to remind themselves about guidelines.”

“We are going to repeat this and what we hope we’ll be seeing is a drawing in of the outliers. That’s the aim. You can debate whether that’s a good thing or not but having a more cohesive group is arguably a good thing.”

“I would imagine that, doing the feedback annually, I would hope to see some sort of change over a two to three year period.”

He said there were particular concerns about the flow-on effect to trainees learning from outliers.

“The reality is there is lots of data showing that the patterns of behaviour you pick up in your training, whether you are a physician or a surgeon, they stay with you over a 10-15 year period. So we would really want outliers involved in training to review their practice very carefully.”