Understanding skin cancer -- diagnosis and treatment
How do I know if it's skin cancer?
All potentially cancerous skin growths must be removed to confirm a cancer diagnosis. Depending on the suspected type of skin cancer, the biopsy techniques vary slightly.
Any potential melanoma requires a surgical biopsy, also called excisional biopsy, in which the entire growth is removed with a scalpel. A pathologist then studies the sample under a microscope to determine whether cancer cells are present.
If melanoma is diagnosed, other tests may be ordered to assess the degree of cancer spread (metastasis). They include:
- Imaging. Your doctor will order one or more tests to look for metastasis. They include CT scan, MRI scan, and chest X-ray.
- Other biopsies. Using a variety of techniques, your doctor may want to get tissue samples from other organs or lymph nodes
Skin growths that are most likely basal cell carcinoma, squamous cell carcinoma, or other forms of non-melanoma can be biopsied in three ways: shave biopsy where the top layer of skin is shaved off under local anaesthetic; punch biopsy where a deeper tissue sample is removed (a small circle the full thickness of the skin); or sometimes incisional or excisional biopsy where a surgical knife is used to remove either a small piece of the suspicious area (taking the full thickness of the skin) or all of the suspicious area. Incisional and excisional biopsies require some stitching of the skin afterwards.
What are the treatments?
Most skin cancers are detected and cured before they spread. Melanoma that has spread to other organs presents the greatest treatment challenge.
Standard treatments for localised basal cell and squamous cell carcinomas are safe and effective and cause few side-effects. Small tumours can be surgically excised, removed with electric current, frozen with liquid nitrogen, or killed with low-dose radiation. Applying an ointment containing an anti-cancer agent called 5- fluorouracil to a superficial tumour for several weeks may also work. Imiquimod cream is a type of treatment for basal cell carcinoma (BCC). Imiquimod cream uses the immune system to attack cancers. It does this by releasing interferon. The idea is that the imiquimod makes cells produce more interferon (a type of disease-fighting protein) , and this then destroys the skin cancer cells.Photodynamic therapy (PDT) uses light therapy in combination with a topical photosensitising agent to destroy cancer cells in basal cell carcinoma.
Larger localised tumours are removed surgically.
In rare cases where basal cell or squamous cell carcinoma has begun to spread beyond the skin, tumours are removed surgically and patients are treated with chemotherapy, radiotherapy, or immunotherapy. Some patients with advanced squamous cell carcinoma respond well to a combination of tretinoin (a type of retinoid which is a derivative of vitamin A) and interferon. Tretinoin also seems to inhibit cancer recurrence in patients who have had tumours removed.