There are three major forms of skin cancer, basal cell carcinoma, squamous cell carcinoma and melanoma. Genetics and UV exposure are the two major factors underlying the development of skin cancer. Skin cancer tends to arise in sun exposed areas but may found anywhere on the body including on the palms and soles, under the nails and in the genital area.
Non-melanoma skin cancers include basal cell carcinoma and squamous cell carcinoma. 90 percent of all non-melanoma skin cancers are associated with UV radiation exposure (including indoor tanning).
Basal cell carcinoma (BCC)
This is the most common form of cancer worldwide. Basal cell carcinomas typically present as a non-healing sore, pearly bump, reddish or pigmented patch or scar-like area. In addition to UV exposure risk factors for basal cell carcinoma include older age, male gender, fair skin and chronic skin infection/inflammation. Basal cell carcinomas are slow growing and very rarely spread to other areas of the body. If left untreated however, basal cell carcinomas may become quite large and disfiguring, therefore early detection and removal is key.
Squamous cell carcinoma (SCC)
These may appear as a firm, red nodule or crusted, scaly patch. In addition to UV exposure risk factors for squamous cell carcinoma include immunosuppression, older age, male gender, fair skin, chronic skin infection/inflammation and precancerous skin lesions such as actinic keratosis. When caught early and treated, most squamous cell carcinomas can be cured. Advanced squamous cell carcinoma has the potential to spread to lymph nodes and distant sites, so lesions should be treated quickly following diagnosis.
Melanoma is the most serious and potentially fatal form of skin cancer. Melanoma may arise from an existing mole or de novo from otherwise normal appearing skin. In men melanoma is most common on the face or trunk and in women on the lower leg.
The ABCDEs of moles can help detect atypical moles and melanoma.
A: Asymmetry. Most melanomas are asymmetrical, meaning if you draw a line through the middle of the lesion the two halves do not match.
B: Border. Melanoma borders tend to be uneven and may have scalloped or notched edges.
C: Colour. Multiple colours may be a warning sign of melanoma. Melanoma may have different shades of brown, tan and black, and even red, white and blue.
D: Diameter. Lesions that grow to 6 mm (about the size of a pencil eraser) or larger may indicate melanoma.
E: Evolving. Any change in size, shape, colour of a lesion, or the development of symptoms such as bleeding, itching or crusting may be a warning sign of melanoma.
Treatment for skin cancer may include:
- Sun protection
- Regular skin examinations
- Mole mapping
- Skin biopsy
- Topical cream
- Electrodessication and curettage
- Excision removal
- Mohs surgery
- Photodynamic therapy