Management of Skin Cancer
This is still the most commonly utilized technique used to treat skin cancer. In some instances, the diagnosis of cancer is obvious following clinical and dermatoscopic examination. After discussion with the patient the initial surgery or excision could be done in such a way that there usually would not be a need for a re-excision.
There are times that a second procedure would be indicated. This would include larger lesions where an incisional biopsy was done to confirm a diagnosis or in cases where the diagnosis was not clear-cut initially and a more conservative excision was performed. The aim for this second procedure would be to achieve appropriate margins (i.e. the uninvolved skin included as part of the excision) that is proven to decrease the chance of the skin cancer to recur. The size of these margins depends on the type of skin cancer.
Mohs micrographic surgery (MMS)
For high risk BCC and SCC this technique is used because the margins are assessed during the procedure and this way one can be sure that the complete tumour is removed before the wound is closed up. The Mohs surgeon excises the lesion or skin cancer and examines the borders of the specimen under a microscope. The borders are marked, so if it is found that a border is involved the surgeon knows where a wider excision is needed. Because this technique requires a lot of expertise and is time consuming it is not as readily available.
The most commonly used form of cryotherapy is to use liquid nitrogen either by applying it with a cotton wool tipped swab directly or by using a cryogun with varying sizes of nozzles. Freezing of the cells leads to cell death. Premalignant lesions (e.g. Actinic Keratosis) and rarely superficial skin cancers (e.g. superficial BCC) can be treated with cryotherapy.
Curettage and electrodesiccation
A curette and electrical current is used to destroy the affected tissue. This technique can be used to treat superficial BCC and SCC in situ.
For Actinic Keratosis, a pre-malignant lesion, 5-fluorouracil (5-FU, Efudex) is the most widely used topical treatment. In individual cases (e.g. frail patients) it could also be used for SCC in situ. The treatment period varies from 4-8 week and it leads to severe tissue inflammation with side-effects including erosion, swelling, redness, itchiness and pain.
Other topical treatments for Actinic Keratosis include methyl aminolevulinate (Metvix) and ingenol mebutate (Picato).
Another topical agent used in the treatment of skin cancer is imiquimod (Aldara) and it is indicated for Actinic Keratosis, superficial basal cell cancer and at times SCC in situ. It is a local immune response modulator and treatment lasts for 6-16 weeks. There can also be a severe local inflammatory response.
The topical agent is applied and after a certain period of time the area is exposed to a light source. The increased photosensitivity leads to destruction of the cells of the lesion. Methyl aminolevulinate used in the treatment of Actinic Keratosis is one of these agents.
This type of treatment is used in older patients or frail patients and in some high risk skin cancers. Radiation can have long term side-effects.
Also rarely used in skin cancer treatment and reserved for extensive local invasion and in cases of distant metastasis.
For more advanced melanoma with a high risk of recurrence or metastasis and for disseminated melanoma there are immune modulating agents. These agents are not commonly used and many of them are still experimental and they are used as adjuvant (“add-on”) treatment following surgery. Some of the agents include ipilimumab, interferon alfa and vemurafenib (BRAF inhibitor).