Melanoma is a dangerous form of skin cancer and the most likely to cause death. Brisbane has one of the highest melanoma rates in the World. 1 in 30 Queenslanders will develop melanoma in their lifetime. If detected early, the survival rate is excellent. Late detection of melanoma is associated with a high mortality rate. Melanomas can be subtle, and present as a new mole, a changing mole or even as a red patch. If you have fair skin, a family history or personal history of skin cancers, or have had significant sun exposure, you are at higher risk of developing melanoma skin cancer. A thirty minute visit with our highly trained skin cancer doctors can be a lifesaving visit.
Important facts on melanoma skin cancer
While anyone may develop melanoma, those with fair complexions and those who have a past history of frequent sunburns particularly as a child have anincreased risk. Other factors that increase your risk include a past history of non-melanoma skin cancer, a family history of melanoma, having many moles on your skin (>10 on your arms OR > 200 o your body), being immunosuppressed (eg: chemotherapy) and increasing age.
The cornerstone of melanoma treatment is surgical excision. For those melanomas that are small and more superficial, extensive surgery is often not necessary. Usually these lesions will be removed along with a margin of normal skin under local anaesthetic. In some cases a second surgery may be required when the pathologist is not satisfied that the margin of normal skin is cancer free.
A wider area of excision is necessary for those melanomas that are thicker (those over 1 mm). In some instances where a large portion of skin has to be removed, a skin graft may be required.
Mohs micrographic surgery is a specialized surgical technique that may be recommended when the melanoma occurs on delicate areas, such as the head and neck.
Radiotherapy has a very limited role in the treatment of melanoma because melanoma is known to be resistant to this form of therapy when compared with other forms of cancer. Radiotherapy may be used as an accessory therapy when obtaining adequate surgical margins has not been possible.
Melanoma develops when pigment containing cells (melanocytes) in the skin are transformed into cancer cells. Although melanoma development is complex and not completely understood, it is thought to involve interactions between environmental factors, genetic changes, and an impairment of DNA repair allowing cells to grow at an uncontrolled rate.
The growth of melanomas is thought to occur in three distinct steps. In the earliest stage, the melanoma may be confined to the most superficial layer of the skin (epidermis) and displays only horizontal growth where it is referred to as melanoma in-situ. As melanoma progresses, it can extend into deeper layers of the skin (the papillary dermis) where it becomes known as microinvasive melanoma. In the more advanced cases, melanoma continues to grow vertically and spread even deeper where itinvades the dermis of the skin where it then has the ability to spread to other areas of the body (metastasize), and is referred to as invasive melanoma.
Melamona may initially present itself as a new or unusual looking mole, freckle or patch on the skin. Melanoma can vary in appearance ranging from brown, tan, pink, red black or even blue. Despite being derived from pigment cells, not all melanomas have a colour, these melanomas are referred to as amelanotic melanoma. Melanomas are often asymmetric and may have an irregular border. In the early stage of growth where they remain on the superficial layer of the skin they are often flat. With further growth or as the melanoma invades deeper layers of the skin it may become thicker and become raised. Melanomas may be itchy or tender and with further growth of the lesions they may become crusted over and bleed.
Because melanomas can present in a variety of ways and have features that vary, it is advisable to get you’re my skin clinic doctor or dermatologist to assess any new moles or any lesions of concern to you.
There are four main subtypes of melanoma: superficial spreading melanoma, nodular melanoma, lentigomaligna melanoma, and acrallentiginous melanoma. Rarer subtypes of melanoma include nevoid melanoma, desmoplastic melanoma, clear cell sarcoma, and solitary dermal melanoma.
Superficial spreading melanoma accounts for the majority of melanomas comprising 50-80% of all melanoma diagnoses. As its name suggests, it is a form of melanoma in which only the superficial layer of the skin is affected and the melanoma has only grown horizontally along the skin surface and vertical (deeper) growth has not yet occurred. It is most frequently seen on those areas of skin exposed to the sun such as the back in men and the lower limbs in women, however it may occur on any region of the body. These melanomas arise de novo yet can also occur within a pre existing mole.
When examined, a superficial spreading melanoma appears multicolored with a well definedand often irregular border. Typical presentations include lesions that have multiple shades of tan, brown, black, grey, purple, pink, and, rarely, blue areas and may possibly have small or localised whitish areas (hypopigmentation).
20 – 30% of diagnosed melanomas are of the Nodular melanoma type. This type of melanoma is characterized by the early onset of growth in a vertical direction, meaning cancer cells are seen in the deeper layers of the skin at an earlier time frame. Nodular melanoma is more common in men, and usually found on the trunk in men and legs in women.On examination, they appear as a uniformly dark brown, black, or blue-black pigmented lesions.
Lentigomaligna melanoma is seen most often in the elderly population, particularly those with a history of sun-damaged skin. This melanoma has a predilection for those areas of the skin regularly exposed to the sun such as the temples, nose, forehead, neck, and forearms.
On examination, lentigomaligna melanoma commonly presents as a slowly enlarging patch that is flat with variable pigment that may be tan, brown, and black in appearance. Additionally, the tumor is stereotypically asymmetrical with irregular borders. Lentigomaligna, while often small initially, can reach several inches in diameter if left untreated. This melanoma may take many years to reach the invasive stage of growth, however, immediate treatment is required if this melanoma is diagnosed.
Acrallentiginous melanoma is not a common melanoma seen in Brisbane and is most often reported in African American populations and those with darker complexions. It is the rarest subtype of melanoma, accounting for less than 5% of all melanomas.These melanomas are characteristically found on hairless areas of the body such as the nail bed, the palms and the underside of the feet.
On examination, an acrallentiginous melanoma regularly develops as a unevenly colored patch, usually brown or black, that has an irregular border and increases in size with time.The surface may feel raised to touch particularly when the tumor grows deeper into the skin and becomes invasive.
When this melanoma occurs in the nail bed it often appears as a brown or black longitudinal line extending from the cuticle to the tip of the nail.
Should a lesion be suspected of being a melanoma is should be surgically excised along with a 2 to 3mm margin of normal skin surrounding the lesion. Following excision, this skin sample will be sent to a pathology laboratory where it can be examined under a microscope to confirm or rule out the diagnosis of melanoma. Smaller biopsies are avoided to improve diagnostic ability and also to attempt to remove the cancer before it has a chance to spread any further.
Following a confirmatory biopsy, the pathologist will provide a description of the melanoma based on specific features that will help guide further management. Further excision of surrounding tissue may be necessary to achieve appropriate clearance and to reduce risk of recurrence either at the site or of metastatic spread.
A biopsy of the lymph node that is the first in the chain of lymph nodes associated with the melanoma (Sentinel lymph node) is usually recommended for those melanomas that are more than 1 mm deep. The usefulness of a lymph node biopsy is in its ability to provide important prognostic information. Whether or not removing multiple lymph nodes (regional lymphadenectomy) provides any benefit to the patients survival is still not well known.
Superficial melanomas usually have a good prognosis.
Following the diagnosis and treatment of a melanoma there will be a life long risk of developing a second melanoma in the future. For this reason it is imperative that regular skin checks are carried out to ensure the early detection and management of new/recurrent tumors.
Self skin examinations are recommended along with regular follow up with your doctor or dermatologist. Suggested intervals of follow up with your doctor are six-monthly for five years for patients with stage 1 disease and every three months for five years for patients with stage 2 or 3 disease with yearly visits thereafter.