Study shines light on characteristics of aggressive melanomas

East Melbourne, Australia-According to a new study, melanomas are more likely to grow rapidly if they are thicker, symmetrical, elevated, have regular borders or have symptoms.

Additionally, rapidly progressing melanoma is more likely to occur in older men and people with fewer moles and freckles, and its cells tend to divide more quickly and have fewer pigments than those of slower-growing cancers.

Those are the major findings of a new study reported in the December issue of Archives of Dermatology. The study was conducted by researchers at the Peter MacCallum Cancer Center here. Its objective was to attempt to identify frequency, growth rate and associations of melanoma with a rapid growth rate.

The researchers investigated melanoma growth rate in 404 patients (222 of whom were male, 182 female, average age 54.2) suffering from invasive melanoma. Dermatologists examined participants’ skin, the number of typical and atypical moles was recorded, and patients were interviewed after diagnosis, preferably in the presence of a friend or family member. The researchers gathered information about demographics, skin cancer risk factors, the characteristics of the tumor and whether the patient, a family member of friend, or a physician first detected the cancer.

All patients and their families were asked to recall the date when they first noticed a spot on their skin from which the melanoma later developed, then the date when they noticed changes. The researchers used these two dates, the date that the melanoma was removed, and the thickness of the tumor at the time of removal to estimate the approximate rate of growth.

The study found that about one-third of all the melanomas (141) grew less than 0.1 millimeters per month, another one-third (136) grew between 0.1 millimeters and 0.49 millimeters per month, and one-third grew by 0.5 millimeters or more per month. A high rate of growth was associated with tumor thickness, ulceration, amelanosis, regular borders, elevation and symptoms. Faster-growing melanomas were more likely to occur in individuals 70 years or older, in men and in individuals with fewer moles and freckles. Factors that were not associated with the rate of growth were the number of atypical moles or solar lentigines, history of sun damage or sunburns, skin type, eye color, family or personal history of melanoma and current or childhood sun exposure.

The study concludes that awareness of clinical features of faster-growing melanomas can help ensure that aggressive cancers are diagnosed and treated quickly.