Mohs microsurgery

Mohs microsurgery, also called Mohs micrographic surgery, removes skin cancer while the edges of the removed tissue are examined under a microscope during the operation. This allows precise removal with checks of the tissue margins.

Mohs is used to treat skin cancers, including basal cell carcinoma and squamous cell carcinoma. For early tumours without lymph-node involvement, treatments studied alongside Mohs include conventional surgical removal, external-beam radiation and brachytherapy, a form of radiation treatment. These are different treatment options, not automatically interchangeable choices for every tumour.

Invasive melanoma requires a separate comparison. Mohs has been studied against wide local excision, which removes the tumour with a surrounding margin of tissue. Patients receiving Mohs in these studies were generally older and had thinner melanomas, so the comparisons do not establish which operation gives better outcomes for otherwise similar patients.

For early basal cell and squamous cell skin cancers classified as T1–T2N0, meaning early tumours without lymph-node involvement, a pooled analysis included 21,371 patients across several treatments. The estimated rate of cancer returning after Mohs was 0.2% at one year, with a statistical uncertainty range of 0% to 0.6%. The 21,371 patients were the total across all treatments, not the number who had Mohs. Cancer control at one year was similar across the treatments studied. This short-term result is not a lifetime cure rate or an individual prediction.

Appearance after treatment was also studied, but the Mohs evidence on cosmetic results came from only one study. Differences in which patients received each treatment and how results were reported make it difficult to conclude that one treatment gives a better cosmetic result.

Microscopic examination during Mohs can sometimes reveal an unexpected finding separate from the original tumour. Some findings are benign, while others can change the treatment plan and require further treatment.

Opioid pain medicines can lead to dependence even after a short postoperative prescription. They are not recommended as a routine prescription for every patient after Mohs surgery and reconstruction.

Pain relief after Mohs surgery and reconstruction does not automatically require an opioid prescription. Expert recommendations do not support prescribing these medicines routinely to everyone undergoing the procedure.