Not every skin cancer needs Mohs surgery. That is one of the most important things to understand when a biopsy comes back as basal cell carcinoma or squamous cell carcinoma.
Mohs micrographic surgery is a specialized technique that removes skin cancer in stages while examining the tissue margins during the procedure. It can offer a very high cure rate while preserving as much healthy tissue as possible—but whether it is the right treatment depends on the cancer, the location, the pathology, and the patient.
What makes Mohs surgery different?
With standard excision, a skin cancer is removed with a planned margin of normal-appearing skin and the specimen is sent to a laboratory for processing. With Mohs surgery, the surgeon removes a thin layer, maps it, examines the margins microscopically, and removes another targeted layer only where cancer remains.
That margin-control approach is especially useful when tissue preservation matters or when a tumor has features that increase the risk of recurrence.
When is Mohs commonly considered?
Dermatologists often consider Mohs when one or more of the following apply:
- The cancer is on a cosmetically or functionally important area such as the nose, eyelid, ear, lip, scalp, hand, foot, or genital skin.
- The tumor is large, aggressive, poorly defined, or has higher-risk features on pathology.
- The skin cancer has returned after prior treatment.
- The cancer developed in previously irradiated skin or near a scar.
- Preserving as much healthy tissue as possible is especially important.
These are not automatic rules. A small, low-risk skin cancer may be treated very effectively with standard excision, electrodesiccation and curettage, topical therapy, or another approach depending on the diagnosis and location.
Does every basal cell carcinoma need Mohs?
No. Basal cell carcinoma is very common, and many lesions can be treated without Mohs. The decision depends on factors such as tumor subtype, size, borders, anatomic site, whether it has been treated before, and the patient’s overall health.
A small, well-defined basal cell carcinoma on the trunk is a very different clinical problem from a recurrent infiltrative basal cell carcinoma on the nose.
What about squamous cell carcinoma?
Mohs may be particularly useful for squamous cell carcinomas that have a higher risk of recurrence or spread, are located in high-risk areas, have poorly defined borders, have returned after treatment, or show aggressive features.
The pathology report matters. So does the physical examination. Treatment decisions should be based on the entire clinical picture rather than the word “cancer” alone.
What happens on the day of Mohs surgery?
Mohs surgery is usually performed with local anesthesia. The visible tumor is removed with a thin layer of surrounding tissue. The tissue is processed and examined while you wait. If cancer remains at an edge, the surgeon removes another layer only from that involved area. The process continues until the margins are clear.
Once the cancer is removed, the wound may be closed with stitches, reconstructed with a flap or graft, or allowed to heal on its own depending on the size and location.
Why does tissue preservation matter?
On areas such as the eyelid, nose, ear, and lip, every millimeter can matter for function and reconstruction. By checking the margins during surgery and removing additional tissue only where cancer remains, Mohs can help minimize unnecessary removal of healthy skin.
How does a dermatologist decide?
The recommendation usually combines the biopsy diagnosis with the tumor’s size, location, clinical borders, prior treatment history, pathology features, patient health, and reconstructive considerations. In some cases, more than one treatment is reasonable and the advantages and tradeoffs can be discussed.
Learn more about Mohs surgery at Borealis Dermatology and our medical dermatology services.
Borealis Dermatology sees patients in Garden City, Syosset, and Bellerose. Visit our locations page or request an appointment.