Once your doctor identifies that you have a lesion that may be suspicious for skin cancer, or is clearly identifiable as a skin cancer, the next step will be to either biopsy the lesion with a view to sending off to the pathologist for identification OR it could be surgically removed as a final treatment for removing the skin cancer definitively.
Before any procedure is performed, it will be necessary to numb, or anaesthetise the skin. This process involves injecting a local anesthetic or chemical which will prevent pain impulses travelling along nerves from your skin to your brain, preventing the sensation of pain. The anesthetic is mostly administered by an injection through and under the skin, beneath the area where the procedure will be performed. A syringe with a very small gauge needle is used to slowly inject the local anaesthetic into the tissue. If injected slowly and with a very small gauge (25-30 gauge) needle, pain of the injection is minimized to a period of 20 – 60 seconds for a small procedure. The pain is comparable to a mild green ant bite but passes very quickly as the tissue becomes numb. A sting will be felt as the needle goes through the skin and then as the local infiltrates into the tissue. The anesthetic is then allowed to take effect over the next 10 minutes or so. Once working, the doctor will test to ensure the area is numb and pain free before commencing the procedure. The sensation of touch, pressure and temperature may still be felt but all pain should be absent. Lignocaine is usually the preferred local anesthetic and is often combined with adrenaline to minimize bleeding and prolong the duration of action.
Topical anesthetic in the form of applied patches to the skin are sometimes used, particularly if there is a planned procedure. Emla patches are a prime example. They may be used in conjunction with injectable local anaesthetic and can be
The majority of skin cancers will be excised under local anaesthetic. For larger more complex procedures, particularly around the face and head, or in someone who may be too anxious (especially children), a general anaesthetic may be used. This will be in a hospital or day surgery setting and will not be the realm of The Flying Skin Cancer Doctor.
Your doctor will look to perform a skin biopsy for any lesions that are suspicious for skin cancer. This procedure may also be performed as a diagnostic tool for many other general skin diseases where the diagnosis is unclear. The biopsy process involves taking a small piece of skin from a lesion or a rash and the sample is placed in a jar of formalin before sending to a pathologist who will slice the sample into thin slices before examining under a microscope.
In the setting of skin cancer, the biopsy conveys the following information and allows the doctor to plan how the cancer is treated:
Diagnosis of the lesion: benign or cancerous
The aggressiveness of a cancer
The stage of a cancer (especially for Melanoma)
In some cases where the edge of the cancer stops
Once this information is known, a skin cancer will be surgically removed with a surrounding margin of normal skin around the cancer. This will vary for each type of cancer and each stage of melanoma.
A punch biopsy is usually reserved for Non Melanoma Skin Cancer (NMSC). The procedure is similar to that of a paper hole punch. A small metal punching device (like a tiny cookie cutter) is used to take a small circle of skin from the lesion once the skin has been anaesthetised. The punch biopsy is most commonly 3 mm in diameter but can vary from 2 mm to 6 mm. A small dressing is applied and in some cases a stitch may be placed before the dressing. The remaining hole usually heals within 5-10 days.
A shave biopsy involves a shallow to deep shave of a lesion over a wider diameter than a punch biopsy. It is good for shallow lesions but especially for pigmented lesions where melanoma may b suspected and we want to ensure the whole lesion is removed to ensure adequate pathological diagnosis of the whole lesion. A shave biopsy blade or a scalpel is used and the remaining shallow ulcer is dressed without sutures and heals over 1-3 weeks.
Curettage is the process of scooping the tissue of a lesion with a curette like scooping ice cream. It is commonly used as part of treatment for superficial skin cancers like BCC and Intraepidermal Carcinomas where the soft cancerous tissue easily comes away from the healthy tissue beneath. Where treatment is the objective, there will often be a series of three curettings followed by electrical diathermy to electrically burn the tissue creating effective removal of superficial cancers.
An incisional biopsy involves the removal of a larger ellipse of skin from a lesion through the full thickness of the skin. Sutures will normally be required to close the area where the ellipse has been removed.
This refers to the surgical removal of a whole lesion with a surrounding margin of normal tissue. It is normally performed as an ellipse with a scalpel and the defect is closed with sutures in the deep tissue and also on the surface. In some cases, a complicated flap may be constructed to fill the defect and then sutured closed or a skin graft from another site may be sutured into the defect.
