Melanoma is a form of skin cancer that occurs when the cells that produces pigment called melanocytes, which give colour to the skin become cancerous. Melanomas can occur anywhere on the body.
Melanoma often spreads, making it one of the most deadly type of cancer. Risk factors for melanoma include overexposure to the sun.
Most pigment cells are found in the skin, but melanoma can also occur in the eyes, a condition called ocular melanoma and other parts of the body, including, the intestines (but very rare). It is uncommon in people with darker skin.
Melanomas can develop anywhere on the skin, but certain areas are more prone than others. In men, it is most likely to occur on the back and chest while in women, it mostly affects the legs. Other common sites are the neck and face.
Stages of Melanoma
The stage at which melanoma is diagnosed will indicate how far it has already spread and what kind of treatment is appropriate.
One method of staging melanoma describes the cancer in five stages, from 0 to 4.
Stage 0: The cancer is only in the outermost layer of skin and is known as melanoma.
Stage 1: The cancer is up to 2 millimeters (mm) thick. It has not yet spread to lymph nodes or other sites.
Stage 2: The cancer is at least 1.01 mm thick and it may be thicker than 4 mm. It may or may not be ulcerated, and it has not yet spread to lymph nodes or other sites.
Stage 3: The cancer has spread to one or more lymph nodes or nearby lymphatic channels, but not to far sites. The original cancer may no longer be visible. If it is visible, it may be thicker than 4 mm, and it may also be ulcerated.
Stage 4: The cancer has spread to distant lymph nodes or organs, such as the brain, lungs, or liver.
Types of Melanoma
There are four types of melanoma.
Superficial spreading melanoma: This is the most common, and found on the trunk or limbs. The cells tend to grow slowly, before it spreads across the skin surface.
Nodular melanoma: It is the second most common type, appearing on the trunk, head, or neck. It tends to grow more quickly than other types, assuming a red coloration as it grows.
Lentigo maligna melanoma: This is less common, it affect older people, especially in parts of the body that have been exposed to the sun over several years. It starts as a Hutchinson’s freckle, or lentigo maligna, which looks like a stain on the skin. It usually grows slowly.
Acral lentiginous melanoma: This is the infrequent kind of melanoma. It normally appears on the palms of the hands, soles of the feet, or under the nails. It is more likely in people with darker skin and is not linked to sun exposure.
Causes of Melanoma
People with certain types of skin are more susceptible to to developing melanoma, and the following factors are linked to an increased frequency of skin cancer:
- high freckle density or tendency to develop freckles after sun exposure
- high number of moles
- five or more atypical moles
- presence of actinic lentigines, small gray-brown spots, also known as liver spots, sun spots, or age spots
- giant congenital melanocytic nevus, brown skin marks that present at birth, also called birth marks
- pale skin that does not tan easily and burns, plus light-colored eyes
- red or light-colored hair
- high sun exposure, particularly if it produces blistering sunburn, and especially if sun exposure is intermittent rather than regular
- age, as risk increases with age
- family or personal history of melanoma
- having an organ transplant
Of these, only high sun exposure and sunburn are avoidable.
Avoiding overexposure to the sun and preventing sunburn can considerably lower the risk of melonama skin cancer.
Symptoms of Melanoma
- skin changes, such as a new spot or mole or a change in color, shape, or size of a current spot or mole
- a skin sore that fails to heal
- a spot or sore that becomes painful, itchy, or tender, or which bleeds
- a spot or lump that looks shiny, waxy, smooth, or pale.
- a firm red lump that bleeds or appears ulcerated or crusty
- a flat, red spot that is rough, dry, or scaly
The ABCDE examination of skin moles is also a key way to reveal suspect lesions. It describes five simple characteristics to look out for in melanoma appearance:
Asymmetric: normal moles are often round and symmetrical, whereas one side of a cancerous mole is likely to look different from the other side – not round or symmetrical.
Border: this is likely to be irregular rather than smooth – ragged, notched, or blurred.
Color: melanomas tend not to be of one color but to contain uneven shades and colors, including varying black, brown, and tan, and even white or blue pigmentation.
Diameter: a change in the size of the mole, or a mole that is larger than a normal mole (more than a quarter inch in diameter) can indicate skin cancer.
Evolving: a change in a mole’s appearance over a period of weeks or months can be a sign of skin cancer.
Treatment of Melanoma
The treatment of melanoma is similar to that of other cancers. However, unlike many internal cancers, it is easier to access the cancer to completely remove it. Surgery is mostly used for the treatment of melanoma. For surgery, the lesion and some of the normal tissue around it is removed. A biopsy may be taken at the same time.
If melanoma covers a large area of skin, a skin graft may be required. If the cancer may have penetrated into the lymph nodes, a lymph node biopsy may be done.
Other treatments for skin cancer include:
- Biological therapy – which involves using drugs that work with the immune system.
- Photodynamic therapy involves using a combination of light and drugs, and radiation to treat melanoma.
Avoiding too much exposure to ultraviolet radiation can reduce the risk of skin cancer. Below are list of things to note;
- avoid sunburn
- put on clothes that protect against the sun
- using sunscreen with a minimum sun protection factor (SPF) of 15, but preferably SPF 20-30, with 4- or 5-star UVA protection
- liberally applying sunscreen about half an hour before going out, and applying it again after half an hour
- reapplying every 2 hours and after swimming to maintain adequate protection
- avoiding the highest sun intensity between 11 am and 3 pm by finding shade.
- protecting children by keeping them out of direct sunlight, instead keep them in the shade, with clothing, and by applying SPF 50+ sun screen.