Incidence and anatomic presentation of cutaneous malignant melanoma in central Canada during a 50-year period: 1956 to 2005
Accepted 11 January 2009. published online 24 April 2009.
Background
Incidence rates of cutaneous malignant melanoma (CMM) have increased worldwide. Long-term studies examining rates and anatomic site-specific incidence on a population-based level are infrequent.
Objective
We sought to examine the historical changes in the incidence and anatomic site presentation of CMM during a 50-year period in Manitoba, Canada.
Methods
Using population-based data, all first diagnoses of CMM reported between 1956 and 2005 were identified. Age-specific rates, age-standardized incidence rates, and anatomic sites were recorded.
Results
Incidence rates of CMM slowed for each sex beginning in 1981 for female patients and 1992 for male patients. Annual percent change revealed decreasing rates among male patients younger than 40 years (1992-2005: –5.3% [P = .03]) and female patients younger than 40 years (1987-2005: –1.8% [P = .15]). Similarly, middle-aged individuals (age 40-59 years) also had diminished annual percent change (men 1992-2005: 0.6% [P = .65]; women 1983-2005: –0.3% [P = .68]). The annual percent change for older men and women (60-79 and ≥80 years) continued to increase. Anatomic site-specific analyses revealed that the trunk was the most frequent site of CMM for young male patients (<60 years) whereas the lower extremities were the most common among young female patients (<60 years). Incidence rates for each site, however, are slowing. Among those aged 60 years and older, the rates for each anatomic site increased.
Limitations
Determining changes in tumor thickness would have been useful in determining whether the nature of tumors have changed over time; however, this is not recorded in our registry.
Conclusion
The rates of CMM are slowing; however, this change is confined to younger individuals. Anatomic site-specific CMMs are changing; rates among older individuals continue to increase for both sexes.
aFaculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
bDepartment of Internal Medicine, Section of Dermatology, Section of Hematology and Oncology, University of Manitoba, Winnipeg, Manitoba, Canada
cDepartment of Community Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
dDepartment of Epidemiology and Cancer Registry, CancerCare Manitoba, Winnipeg, Manitoba, Canada
eDepartment of Surgery, Section of Plastic Surgery, University of Edmonton, Edmonton, Alberta, Canada
Correspondence to: Alain A. Demers, PhD, Department of Epidemiology and Cancer Registry, CancerCare Manitoba, 675 McDermot Ave, Winnipeg, Manitoba, Canada R3E 0V9.
ABSTRACT