types of cancer

Skin Cancer


Skin cancers (skin neoplasms) are named after the type of skin cell from which they arise. Basal cell cancer originates from the lowest layer of the epidermis, and is the most common but least dangerous skin cancer. Squamous cell cancer originates from the middle layer, and is less common but more likely to spread, and if left untreated, becomes fatal. Melanoma, which originates in the pigment-producing cells (melanocytes), is the least common but most aggressive, most likely to spread, and if untreated, becomes fatal. While most cases are caused by over-exposure to UV rays from the sun or sunbeds, treatment is generally via surgical removal.


There are a variety of different skin cancer symptoms. These include changes in the skin that do not heal, ulcering in the skin, discolored skin, and changes in existing moles, such as jagged edges to the mole and enlargement of the mole.


Ultraviolet radiation from exposure to sunlight is the primary cause of skin cancer. Other factors that play a role include:

  • Smoking tobacco.
  • HPV infections increase the risk of squamous cell carcinoma.
  • Some genetic syndromes, including congenital melanocytic nevi syndrome, which is characterised by the presence of nevi (birthmarks or moles) of varying size which are either present at birth, or appear within 6 months of birth. Nevi larger than 20 mm (3/4″) in size are at higher risk of becoming cancerous.
  • Chronic non-healing wounds. These are called Marjolin’s ulcers based on their appearance, and can develop into squamous cell carcinoma.
  • Ionising radiation, environmental carcinogens, artificial UV radiation (e.g. tanning beds), aging, and light skin colour. It is believed that tanning beds are the cause of hundreds of thousands of basal and squamous cell carcinomas. The World Health Organisation now places people who use artificial tanning beds in its highest risk category for skin cancer.
  • The use of many immunosuppressive medication increases the risk of skin cancer. Cyclosporin A, a calcineurin inhibitor, for example, increases the risk by approximately 200 times, and azathioprine about 60 times.
  • Diagnosis

    A physical exam of the skin is used to evaluate the skin for melanoma. If melanoma is suspected, a skin biopsy will be done. For this, your doctor will remove a sample of skin tissue and send it to a pathologist to be looked at under a microscope. If the biopsy shows melanoma, the pathologist will measure the thickness of the melanoma to find out how advanced the cancer is. Other techniques may include total-body photography to monitor for changes in any mole and to watch for new moles appearing in normal skin. A series of photos of the suspicious lesions may be taken. Then the photos can be used as a baseline to compare with follow-up photos. EVALUATION OF LYMPH NODES Your doctor will do a physical exam that includes checking the lymph nodes to see whether they are larger than normal. This may be followed by a sentinel lymph node biopsy to see whether the melanoma has spread to the lymph system. EVALUATION FOR POSSIBLE METASTASES (SPREAD OF CANCER) A complete medical history and a physical exam are needed to find out whether the cancer has spread (metastasized) to other parts of the body. Imaging tests, including Positron Emission Tomography (PET scan), Computed Tomography (CT scan) or Magnetic Resonance Imaging (MRI), may be used to identify metastases in other parts of the body, such as the lungs, the brain, the liver, or other organs. EARLY DETECTION Skin self-exam is a good way to detect early skin changes that may point to melanoma. A skin self-exam is used to find suspicious growths that may be cancer or growths that may develop into skin cancer (precancers). Adults should examine their skin once every month. Look for any abnormal skin growth or any change in the colour, shape, size, or appearance of a skin growth. Check for any area of injured skin (lesion) that does not heal. Have your spouse or someone such as a close friend help you monitor your skin, especially places that are hard to see such as the scalp and the back. There are other steps one can take, to prevent skin cancer or detect it at an early stage.

  • Be aware of the risk of skin cancer and the steps you can take to prevent it, including staying out of the midday sun, wearing protective clothing, and using sunscreen on exposed skin.
    • Have the doctor examine any suspicious skin changes. He or she may choose to check the skin once a year, or may suggest a skin exam more often, especially if there is:
    • Familial atypical mole and melanoma (FAM-M) syndrome, which is an inherited tendency to develop melanoma. Examine your skin every month and be examined by a doctor every 4 to 6 months, preferably by the same doctor each time.
    • Increased exposure to ultraviolet (UV) radiation, because of job, hobbies or outdoor activities.
    • Abnormal moles called atypical moles (dysplastic nevi). These moles are not cancerous, but their presence is a warning of an inherited tendency to develop melanoma.


    Treatment is dependent on type of cancer, location of the cancer, age of the patient, and whether the cancer is primary or a recurrence. Treatment is also determined by the specific type of cancer. For a small basal cell cancer in a young person, the treatment with the best cure rate (Mohs surgery or CCPDMA) might be indicated. In case of an elderly frail man with multiple complicating medical problems, a difficult to excise basal cell cancer of the nose might warrant radiation therapy (slightly lower cure rate) or no treatment at all. Topical chemotherapy might be indicated for large superficial basal cell carcinoma for good cosmetic outcome, whereas it might be inadequate for invasive nodular basal cell carcinoma or invasive squamous cell carcinoma. In general, melanoma is poorly responsive to radiation or chemotherapy. For low-risk disease, radiation therapy (external beam radiotherapy), topical chemotherapy (imiquimod or 5-fluorouracil) and cryotherapy (freezing the cancer off) can provide adequate control of the disease; both, however, may have lower overall cure rates than certain type of surgery. Other modalities of treatment such as photodynamic therapy, topical chemotherapy, electrodesiccation and curettage can be found in the discussions of basal cell carcinoma and squamous cell carcinoma. In the case of disease that has spread (metastasized), further surgical procedures or chemotherapy may be required. Currently, surgical excision is the most common form of treatment for skin cancers. The goal of reconstructive surgery is restoration of normal appearance and function. The choice of technique in reconstruction is dictated by the size and location of the defect. Excision and reconstruction of facial skin cancers is generally more challenging due to the presence of highly visible and functional anatomical structures in the face. When skin defects are small in size, most can be corrected with simple repair, where skin edges are approximated and closed with sutures. This will result in a linear scar. If the repair is made along a natural skin fold or wrinkle line, the scar will be hardly visible. Larger defects may require repair with a skin graft, local skin flap, pedicled skin flap, or a microvascular free flap. Skin grafts and local skin flaps are, by far, more common than the other listed choices. Skin grafting is patching of a defect with skin that is removed from another site in the body. The skin graft is sutured to the edges of the defect, and a bolster dressing is placed atop the graft for seven to ten days, to immobilise the graft as it heals in place. There are two forms of skin grafting: split thickness and full thickness. In a split thickness skin graft, a shaver is used to shave a layer of skin from the abdomen or thigh. The donor site, regenerates skin and heals over a period of two weeks. In a full thickness skin graft, a segment of skin is totally removed and the donor site needs to be sutured closed. Split thickness grafts can be used to repair larger defects, but the grafts are inferior in their cosmetic appearance. Full thickness skin grafts are more acceptable, cosmetically. However, full thickness grafts can only be used for small or moderate sized defects. Local skin flaps are a method of closing defects with tissue that closely matches the defect in colour and quality. Skin from the periphery of the defect site is mobilised and repositioned to fill the deficit. Various forms of local flaps can be designed to minimise disruption to surrounding tissues and maximise cosmetic outcome of the reconstruction. Pedicled skin flaps are a method of transferring skin with an intact blood supply from a nearby region of the body. An example of such reconstruction is a pedicled forehead flap for repair of a large nasal skin defect. Once the flap develops a source of blood supply form its new bed, the vascular pedicle can be detached.

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