Skin cancer is the most common of all human cancers.
Cancer occurs when normal cells undergo a transformation and grow and multiply without normal controls.
As the cells multiply, they form a mass called a tumour.
Tumours are cancerous only if they are malignant. This means that they encroach on and invade neighbouring tissues (especially lymph nodes) because of their uncontrolled growth.
Tumours may also travel to remote organs via the bloodstream.This process of invading and spreading to other organs is called metastasis.
Tumours overwhelm surrounding tissues by invading their space and taking the oxygen and nutrients they need to survive and function.
Basics of skin cancers
The vast majority of skin cancers are basal cell carcinomas and squamous cells carcinomas. While malignant, these are unlikely to spread to other parts of the body. They may be locally disfiguring if not treated early.
A small but significant number of skin cancers are malignant melanomas. Malignant melanoma is a highly aggressive cancer that tends to spread to other parts of the body. These cancers may be fatal if not treated early.
Like many cancers, skin cancers start as precancerous lesions. These precancerous lesions are changes in skin that are not cancer, but could become cancer over time. Medical professionals often refer to these changes as dysplasia.
Types of skin cancers
Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), and Melanoma are the three major types of skin cancer. The first two skin cancers are grouped together as non-melanoma skin cancers. Other unusual types of skin cancer include Merkel cell tumours and Dermatofibrosarcoma protruberans.
Symptoms of skin cancer
The general warning signs of skin cancer include:
Any change in size, color, shape, or texture of a mole or other skin growth.
An open or inflamed skin wound that won't heal.
Melanoma, the most dangerous type of skin cancer, may appear as:
A change in an existing mole.
A small, dark, multi-coloured spot with irregular borders, either elevated or flat, that may bleed and form a scab.