MOHS MICROGRAPHIC SURGERY & CUTANEOUS RECONSTRUCTION
Mohs Micrographic Surgery
Named after Frederic E. Mohs, the founder and originator of Mohs Micrographic Surgery, this procedure is a specialised form of surgery to remove skin cancers. It involves a precise surgical technique where a complete excision of skin cancer is attained via microscopic margin control. Also known as Mohs surgery, it offers the highest cure rates whilst ensuring the preservation of healthy tissue is maximised.
It has gained recognition to become the treatment of choice in Singapore for common skin cancers like high-risk Basal Cell Carcinoma and Squamous Cell Carcinoma. The procedure involves progressive removal of the visible portion of the tumour and further tissue at the margin that may include cancerous cells, one layer at a time. After every stage, the excision margins are examined microscopically for any remaining cancer cells whilst the patient is in the treatment facility, and the process will be repeated until all the cancer has been completely removed.
THE MOHS MICROSURGERY PROCEDURE:
- The histological processing takes place on the surgery day via frozen sections and the wound is closed only after all the cancer is removed.
- Excision margin is examined through an embedding technique, allowing horizontal sections to be cut involving all the deep and radial excision margins.
- If tumour is still visible, the excision is considered incomplete and the patient is given a further stage of Mohs.
- Closure is performed only after the skin cancer is entirely removed.
- Mapping process and colour coding system allows precise localisation of any remaining cancer, with tissue being removed only if it contains cancer.
- Helps to preserve healthy tissue by minimising removal of surrounding normal skin.
The Mohs surgery is recommended if:
- The skin cancer is in cosmetically sensitive sites (e.g. eyelids, nose, ears, lips) to minimise removal of healthy tissue
- The edges of the tumour are clinically not well-defined
- The skin cancer is of an aggressive subtype
- The skin cancer has recurred
- The skin cancer was previously excised, but some cancer cells remain
It is important to note that every patient is different and there may be certain characteristics of the tumour or location of the tumour for which a different method may be suitable, such as standard wide excision. Typically, Mohs surgery is favoured by patients, especially in cosmetically-sensitive areas as the procedure is tissue-sparing and recommended by surgeons if the edges of the tumour are clinically not well-defined or is of a high-risk subtype.
A complete assessment from a dermatologist and Mohs micrographic surgeon is imperative to discuss both options and select a plan of management based on tumour characteristics and patient preferences. Based in Singapore, Dr Angeline Yong is a dermatologist and dermatological surgeon who sub-specialises in skin cancers, Mohs Micrographic Surgery and cutaneous reconstruction. An integral member of both the skin cancer division and Mohs Micrographic Surgery service at the National Skin Centre, Dr Yong has completed a year-long fellowship at St John’s Institute of Dermatology, Guy’s and St Thomas’ NHS Trust, which is the leading, as well as largest, dermatology centre in the United Kingdom.
She is also the first Singaporean to qualify to be admitted as a member of the American College of Mohs Surgery, the leading body that accredits Mohs Micrographic Surgeons in the United States. In addition, she is also an international fellow of the American Society of Mohs Surgery, a member of the American Society of Dermatologic Surgery, and a member of the British Society of Dermatologic Surgery.