Mohs Surgery

Mohs Surgery is the best treatment for non-melanoma skin cancers

  • Best treatment option for non-melanoma skin cancers (basal cell cancer, squamous cell cancer)
  • Best treatment option for higher risk skin cancers in cosmetically sensitive areas (face)
  • Precise and methodical surgical technique using microscope analysis to ensure complete clearance of skin cancer cells
  • It has the highest cancer cure rate and lowest recurrence rate
  • It can achieve the best cosmetic result by preserving healthy skin tissue and minimising surgical wound
Read The Straits Times article on skin cancer and Mohs Surgery by Dr Tay Liang Kiat

What is Mohs Micrographic Surgery?

Mohs Surgery (or Mohs Micrographic Surgery) is a specialised surgical technique used to treat skin cancers which has been developed by Dr Frederic Mohs in the 1930s.
It involves methodically excising the skin cancer progressively in stages with precise microscopic margin control using tangentially cut frozen-section histology.
Amazingly, even with all the medical advancements over the past decades, Mohs surgery is still considered the most effective treatment for non-melanoma skin cancers (basal cell and squamous cell cancers-BCC, SCC), as it is able to achieve the highest cure rates with maximal preservation of healthy skin tissue.
Doctors from different surgical fields have tried their hands at Mohs surgery, but it was only over the past few decades that this surgical technique became fully embraced by dermatologists in many countries. To perform Mohs surgery, the dermatologist needs the skill set to function both as a surgeon and pathologist.

How common are skin cancers in Singapore?

Non-melanoma skin cancers has become a significant public health problem in the western population. The primary cause is sun-damaged skin as a result of cumulative sun exposure.
In Singapore, skin cancer rates are also on the rise in recent years, especially with an ageing population and increasing large group of expatriate Caucasian population residing here.
Skin cancer rates are highest in fair skin Caucasians, and about three times higher in Chinese compared to Malay and Indian population, due to darker skin types having more skin pigment which protects against the damaging ultraviolet rays from sun exposure.
Basal Cell Cancer (BCC) is the commonest skin cancer, followed by Squamous Cell Cancer (SCC) which tend to behave more aggressively. Listed as the top 10 cancers in Singapore, although these skin cancers have low mortality rates, they are locally invasive on the skin and can result in significant symptoms of pain/bleeding, disfigurement and reduced quality of life.
Listed as the top 10 cancers in Singapore, although these skin cancers have low mortality rates, they are locally invasive on the skin and can result in significant symptoms of pain/bleeding, disfigurement and reduced quality of life.

Why is Mohs Surgery recognised as the gold standard treatment for non-melanoma skin cancers?

Many treatment options with variable effectiveness are available to treat non- melanoma skin cancers, such as topical creams, cryosurgery, electrodessication and curettage, photodynamic therapy and oral medications.
Surgical options offer better cure rates, and these include the traditional wide excision and Mohs surgery.
Mohs surgery is the only treatment modality that examines 100% of surgical margins, and has consistently been shown to offer the highest cure rate, lowest recurrence and best cosmetic outcome as compared to other treatment options.
In large medical studies, Mohs Surgery has shown a cure rate of up to 99% for first episode BCC and 97% for first episode SCC, far superior than other skin cancer treatments.

How does Mohs Surgery differ from standard wide excision of skin cancer?

Standard Wide Excision of Skin Cancer

Following standard wide excision of non-melanoma skin cancers, the wound is immediately closed and the tissue specimen sent for histology processing which can take a couple of days.
Histology sections are created at various distances through the tissue specimen and microscopically assessed to determine clearance, however only a small fraction of the actual surgical margins is assessed by the pathologist.
There is a risk of incomplete excisions which add to the stress and burden of patients requiring subsequent re-excision surgeries.

Mohs Surgery of Skin Cancer

Mohs Surgery has the benefit of microscopically examining the entire deep and peripheral surgical margins at the same time.
A methodical Mohs mapping and colour coding system allows precise localisation of any remaining cancer cells, which allows the skin cancer to be excised progressively in stages to ensure that only affected cancer-containing skin tissue is removed.
Mohs Surgery allows wound repair on the same day following confirmation that all the skin cancer cells have been completely removed.
By preserving as much healthy skin tissue, especially important in cosmetically sensitive areas on the face, the wounds are smaller and the cosmetic outcome much better.

Benefits of Mohs Surgery

  • Highest cure rate
  • Lowest recurrence rate
  • Smaller wounds
  • Better cosmetic outcome

What does Mohs Surgery involve?

Mohs Surgery is performed under local anesthesia. It involves a few phases-
Staged excision phase
The visible skin cancer is removed by using specialised surgical excision methods to allow examination of the entire surgical margins.
Processing phase
The specimens are then processed and sectioned using a cryostat machine by a specially trained Mohs Lab technician, stained and mounted on microscope slides.
Histology analysis phase
The Mohs surgeon then interprets the slides and microscopically maps the skin cancer.
If there are still skin cancer cells present, these are further excised based on the precise Mohs micrographic mapping, and then processed on slides again to check for any residual cancer cells.
The above Mohs staged excision and histology analysis is repeated until the entire deep and peripheral surgical margins are completely clear of cancer cells microscopically.
Post-Mohs wound repair phase
Following complete removal of the skin cancer, the Mohs surgeon then proceeds to repair the post-surgical defect, generally with a local skin flap or skin graft.

What types of skin cancer are best treated by Mohs Surgery?

Mohs surgery is widely accepted as the best treatment for high-risk non-melanoma skin cancers (BCC, SCC).
It is most beneficial for skin cancers at high risk of incomplete excision or recurrences, such as those occurring on the head and neck, more aggressive BCC subtypes (infiltrative or micronodular), SCC with higher risk of metastasis (located on the lip, ears, or immunosuppressed patients).
Tumours with ill-defined clinical borders, those arising in post-radiotherapy skin areas, and those recurrent or incompletely excised tumours will require Mohs surgery to ensure complete clearance.
Tumours arising from cosmetically sensitive areas (such as the face, nose, eyelids) will benefit from maximal tissue preservation using the Mohs excision technique.
Increasingly, Mohs surgery has also been used to effectively treat many other types of skin tumours.
DISCLAIMER:
The information written and published on this website is not intended to substitute the recommendations of a trained professional and does not replace a professional consultation.
It is advisable to undergo a formal consultation to help establish a relationship between the doctor and yourself, accurately determine your concerns/problems, and get the appropriate treatments for them.
It is also imperative to note that the contents of the website with respect to treatments, results and pricing can vary from individual to individual, and can only be accurately determined by the doctor upon diagnosis.
Do note that all medical treatments will only be administered upon proper consultation, with the requirement that patients be above 21 years of age to provide legal consent.

Skin Cancer

Meet your Dermatologist

Dr Tay Liang Kiat

Dermatologist
Dr Tay Liang Kiat is a fully accredited Dermatologist who specialises in skin cancers, Mohs micrographic surgery, dermatologic and nail surgery, aesthetic dermatology and laser procedures. With more than 20 years of clinical experience, he also manages other aspects of general ambulatory and inpatient dermatology, including eczema, psoriasis, acne, urticaria, hair loss, children skin issues and other complex medical dermatology. In addition, he has expertise in the use of the latest immunotherapy (biologics) treatment for severe eczema, psoriasis and urticaria.
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