What is melanoma?
The statistics provided in this report include patients diagnosed with in situ and invasive melanoma. Melanoma is most frequently used to describe skin lesions, which develop in skin cells (melanocytes) and usually occurs on parts of the body that have been overexposed to the sun. However, rare melanomas can also start inside the eye or in a part of the skin or body that has never been exposed to the sun, such as the nervous system, mucous membrane (lining of the mouth, digestive tract, etc), soles of the feet, palms, and under the nails. Although it is one of the less common types of skin cancer, melanoma is considered the most serious because it is more likely to spread to other parts of the body, especially if not detected early. The earlier melanoma is found, the more successful treatment is likely to be.
How common is melanoma?
In 2019, 2840 Victorians were diagnosed with melanoma. Of these, there were 1633 males and 1207 females, representing 57.5% and 42.5% of the total Victorian melanoma diagnoses, respectively. The median age at diagnosis of melanoma is 63 years in males and 59 in females (Figure 1 & 2). Accounting for 7.9% of all cancers diagnosed and 2.4% of all cancer-related deaths in 2019, melanoma was the 5th most commonly diagnosed cancer and the 14th most common cause of cancer-related deaths in Victoria.
Trends in melanoma over time
Figure 3 shows that since 1982 incidence of melanoma has increased by an average of 1.7% per year in males and increased by an average of 0.7% in females. Over the past 37 years, mortality from melanoma has decreased by 0.2% per year in males and decreased by 1.5% per year in females.
Melanoma morphology
Figure 4 provides a summary of the different types of cells (morphology) which have caused melanoma. Most melanomas, 58.6%, present as Superficial cell tumours.
Geographical variance in melanoma by local government area
Figure 5 demonstrates variation in age-standardised incidence rates of melanoma by local government areas. Darker shading indicates areas with higher rates of melanoma.
Melanoma in people born overseas
Figure 6 shows the age standardised incidence rates of melanoma in Australian-born Victorians compared to other major migrant groups, over the five-year period 2015 to 2019. The highest age standardised incidence rate for melanoma was 33.5 for males born in the Australia and New Zealand region and the lowest rate of 0.8 was observed in males born in the North-East Asia region. The highest age standardised incidence rate for melanoma was 25.8 for females born in the Australia and New Zealand region and the lowest rate of 1.2 was observed in females born in the Southern and Central Asia region.
Melanoma distribution by stage at diagnosis
Figure 7 shows distribution of melanoma by stage of disease at diagnosis in 2019. In males, Stage 1 accounted for the largest proportion (70.3%) of new diagnoses and Stage unknown accounted for the lowest proportion (3%) of new melanoma diagnoses. In females, Stage 1 accounted for the largest proportion (75.6%) of new diagnoses and Stage 4 accounted for the lowest proportion (2%) of new melanoma diagnoses.
Melanoma five-year relative survival
Figure 8 demonstrates that five-year relative survival has increased for melanoma between 1989-1993 and 2014-2018 from 88% to 92%.