By Age Group
Cancer incidence data are derived from the Ontario Cancer Registry (OCR) operated by Cancer Care Ontario. The OCR contains information on Ontario residents who have been newly diagnosed with all types of malignant cancers, with the exception of basal cell and squamous cell (non-melanoma) skin cancers. Beginning in 2014, the OCR adopted the National Cancer Institute (NCI) SEER standards for counting multiple primaries for cancer cases diagnosed in 2010 and beyond. This standard is more liberal than the previously used case counting rules from the modified version of the International Association of Cancer Registries (IACR). Cancer data presented on this and other HealthSTATS pages only includes cases captured using the more conservative IACR definition for all years in order to maintain comparability over time. As a result, figures presented on HealthSTATS may be lower than those reported by Cancer Care Ontario as they are using the revised counting methodology.
This HealthSTATS page only includes cases of malignant melanomas of the skin. Non-epithelial skin cancers, which are not included in these statistics, represent less than 10% of skin cancers that are tracked by the OCR. These statistics also do not include data for basal cell and squamous cell carcinomas, which are not tracked by the OCR. Exposure to ultraviolet (UV) rays is the most important risk factor for malignant melanomas. Sunlight is the main source of UV rays. Tanning beds and sun lamps are also sources of UV rays.
The rate of new cancer cases (also called the incidence rate) provides a measure of the risk of developing cancer over a given period of time. In 2012 among Simcoe Muskoka residents, there were 141 new cases of malignant melanoma diagnosed with an age-standardized incidence rate for all ages and both sexes of 25 (20.9, 29.3) per 100,000 population. This was significantly higher than the Ontario malignant melanoma incidence rate of 20 (19.2, 20.7) per 100,000.
Figure one below shows the trend in malignant melanoma incidence in both Simcoe Muskoka and Ontario over the 27 year period from 1986 to 2012. The malignant melanoma incidence rates in both Simcoe Muskoka and Ontario increased steadily over this time period. In Simcoe Muskoka, malignant melanoma has increase by an average of 2.5 (2.0, 3.1) per cent per year, which was significantly faster than the overall provincial increase of 1.6 (1.4, 1.9) per cent per year. The Simcoe Muskoka rates have been consistently above the provincial rates over this time-period.
In 2012, the age-standardized incidence rate for malignant melanoma among Simcoe Muskoka males was 33 (26.5, 40.9) per 100,000, which was significantly higher than the female rate of 18 (13.4, 23.5) per 100,000. The 2012 age-standardized malignant melanoma incidence rates for Ontario males was significantly lower than what was observed for Simcoe Muskoka males; however the provincial females rate was not significantly different from the comparable Simcoe Muskoka rate.
Figure two shows the trend in malignant melanoma incidence rates for males and females in Simcoe Muskoka over the 27 year period between 1986 and 2012. The malignant melanoma incidence rates for both males and females in Simcoe Muskoka have increased significantly over this time-period, with an average annual increase of approximately two per cent per year.
By Age Group
The risk of being diagnosed with malignant melanoma increases significantly with age (see figure three). The age-specific malignant melanoma incidence rates between 2007 and 2012 (combined) in Simcoe Muskoka were highest among those 75 years and older at 109 (95.5, 123.9) new cases per 100,000 population. The age-specific malignant melanoma incidence rates in Simcoe Muskoka were significantly higher than the comparable provincial rates for all age groups among adults 45 years of age an older.
The age-specific malignant melanoma incidence rates for Simcoe Muskoka males (figure four) and females (figure five) have increased most substantially among seniors 65 years of age and older over the past quarter of a century. The male and female rates were similar among adults 20 to 64 years of age over this time-period. Male rates were significantly higher than the female rates for seniors 65 years and older over this period of time; however, the rates among female seniors more than tripled while the rates among male seniors doubled.