Dr. Tiago Mestre

Dermatologist

Mohs surgery
Is the gold standard in skin cancer treatment

HPA Magazine 16

It can be considered the most refined, precise and effective technique for the treatment of the most frequent types of skin cancer. 

This surgical technique, offers the highest cure rate in the excision of non-melanoma skin cancers. With this procedure, it is possible to identify and remove the entire tumour, while preserving healthy skin around the lesion. This technique consists of removing the cancer from the skin, layer by layer and examining each one under the microscope, until tumour free margins are obtained, that is, until the tumour has been completely removed (the level of precision and accuracy can reach 99%). This precision is possible since during the surgical procedure practically 100% of the margins are analysed by microscope. Once the tumour free margins are reached, the wound is reconstructed. The advantages of Mohs Micrographic Surgery when compared to conventional surgery are related to this microscopic control of the margins of the tumour during surgery which  allows the biggest cure rate, the smallest surgical wound and the best possible cosmetic outcome. The minimal of healthy skin is removed with the possible highest cure rate. In conventional surgery, the tumour is removed with a standard safety margins and sent to pathological anatomy. The result is usually received within 1-2 weeks. The risk of some cancerous residue remaining may exist and is definitely higher in relation to Mohs surgery, as removal of the tumour is carried out by what can be visualized by the dermatologist. Complex repairs following incomplete excisions of a tumour can cause be a serious problem to resolve. Therefore, high risk tumours in high risk areas, as the face, incomplete excisions or recurrences are formal indications for Mohs Surgery. This issue of “extending the safety margin of the excision” has always been much discussed in dermatological surgery; exiguous margins tend to leave remnants of the tumour, but facilitate reconstruction, while enlarged margins tend to completely remove tumours, but they can produce functional or even aesthetic sequelae, in addition enlarged surgical margins do not always guarantee total tumour removal for aggressive skin cancers. In short, the concept of “safety margin” is based on the supposed prediction of subclinical tumour growth, which, in reality, cannot be anticipated by a basic examination only. In order to perform Mohs micrographic surgery, it is necessary that the specialist has a deep knowledge of skin histology – to permit a microscopic analysis of the skin during surgery, to ensure a complete removal of the cancer, even in areas that are not clinically visible. He must also have surgical knowledge and most importantly reconstruction techniques

Mohs Surgery is also very often used in collaboration with other specialties like Oculoplastics, Plastics or ENT for a multidisciplinary approach and complex cases. 
The name micrographic surgery refers to the precise mapping and orientation performed during Mohs surgery, which allows the tumour to be removed and, at the same time be examined (described above). The term Mohs refers to the name of the creator of the technique, Frederic E. Mohs, who began the procedure in the 1930s. However, with the technological development in medicine, this technique has undergone a huge transformation, especially with the use of the cryostat, a device that allows skin slicing and freezing, so that the tumour can be examined during surgery. It can also be indicated for basal cell carcinomas considered to have a low risk of recurrence, when the objective is to preserve healthy skin.
Whether to reduce the size of the scar, or for areas where there is no excess skin to perform the reconstruction, as is the case, for example, in the auricular regions (ears), eyelids and glans penis. 

MOHS SURGERY IS INDICATED FOR: 

• • Basal cell carcinoma with an increased risk of recurrence;
• • Squamous cell carcinoma (or squamous cell);
• • Dermatofibrossarcoma protuberans (DFSP); 
• • Lentigo Maligna and some other rare skin tumours.

Fellowship trained Mohs surgeons ensure the quality and certification of 1 to 2 years rigorous fellowship program after specialty.
Dr. Tiago Mestre is one of the two fellowship trained Mohs surgeons by the British Society of Dermatological Surgery who perform in Portugal and the only member in the country of the prestigious American College of Mohs Surgery.