In a study published by Olsen et al in JAMA Dermatology, researchers found that in predominantly fair-skinned populations, melanoma incidence differed by age and anatomic site in men and women.
Methods
A cross-sectional analysis of sex- and site-specific trends was performed for white patients diagnosed with melanoma in the United States, Canada, Australia, New Zealand, the United Kingdom, Sweden, Norway, and Denmark from January 1982 to December 2015. Male-to-female incidence rate ratios were calculated both overall and by disease site, and annual percentage rate changes in sex- and site-specific incidence were estimated by regression modeling.
The main outcome measure was male-to-female incidence rate ratios and annual percentage change in rates.
Results
In the entire study period, total incidence of melanoma was higher in men vs women in the United States, Canada, Australia, and New Zealand. Incidence was higher in women vs men in Denmark during the entire study period, in the United Kingdom from 1982 to 1998, and in Norway from 1982 to 1989. In men and women in Sweden, incidence rates were similar for the duration of the study period. The incidence rates were highest in individuals located in the United States and Australia for the entire time period. In all countries included in the analysis other than Sweden and Denmark, there was an increase in incidence noted in the early- to mid-1990s, followed by either stabilization or more gradual increased in incidence through 2015.
KEY POINTS
- In the entire study period, total incidence of melanoma was higher in men vs women in the United States, Canada, Australia, and New Zealand. Incidence was higher in women vs men in Denmark during the entire study period, in the United Kingdom from 1982 to 1998, and in Norway from 1982 to 1989.
- In all populations, men had higher rates of melanoma located on the head and neck and torso than women, and lower rates of melanoma located on the lower limbs. Melanomas of the upper limbs occurred with similar frequency in men and women.
- The male-to-female incidence rate ratios increased log linearly with age.
In all populations, men had higher rates of melanoma located on the head and neck and torso than women, and lower rates of melanoma located on the lower limbs. Melanomas of the upper limbs occurred with similar frequency in men and women.
The male-to-female incidence rate ratios increased log linearly with age. Women younger than age 45 had excess melanomas in all populations, yet men age 69 and older had excess melanomas. However, incidence rate ratios were less than 1 in all populations younger than 45 years and were greater than 1 in those older than 69 years.
When examining incidence rate ratio differences by age and anatomic site, the researchers found that incidence rate ratio increases were mostly associated with changes in the incidence of melanomas of the head and neck and torso, but that melanomas occurred more frequently on the lower limbs in women than men in all populations at all ages and this ratio remained mostly constant across the study period. Male excess for trunk melanoma occurred at a younger age than for head and neck melanoma (mean = 45.0 vs 52.5 years) and female excess of melanoma on the lower limbs was apparent at an average of 27.5 years of age.
The age at which the melanoma incidence in men exceeded the melanoma incidence in women differed by population, being achieved by individuals aged 45–49 years in Australia and individuals aged 65–69 years in Denmark.
The study authors concluded, “In predominantly fair-skinned populations, melanoma incidence appears to differ systematically and consistently between men and women by age and anatomic site.”
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
