Toronto—The prevalence of non-melanoma skin cancer is on the rise in Ontario, climbing 30 percent from 2003 to 2017 after a period of decline decades ago, says a study by Toronto researchers.
Scientists from the University of Toronto and Women’s College Hospital analyzed data from the Institute for Clinical Evaluation Science (ICES) on the skin cancer known as keratinocyte carcinoma, over a 20-year period.
They included cancers that formed in the cells of the lower or upper layers of the skin, as opposed to the melanin-producing cells deeper in the epidermis, which are more severe.
In 2017, the incidence rate reached 369 per 100,000 males and 345 per 100,000 females.
Non-melanoma skin cancers are the most common malignancies in Canada and “can cause substantial disease and affect quality of life” despite low mortality, the study authors said. But the study also shows that the annual death rate for skin cancer is rising, almost five-fold to 30.53 deaths per 100,000 in 2017, up from 6.39 deaths per 100,000 in 1998.
While the majority of deaths occurred in adults over the age of 65, the study found that the annual incidence rate of new cases was highest among people under the age of 35.
One of the study’s co-authors and Dr. D., a dermatologist and skin cancer surgeon at Women’s College Hospital. An-Wen Chan said he has seen clinically increasing rates of the disease, prompting his team to formally examine the data. province.
“When we looked deeper into the data and classified patients by age and gender, very clear patterns emerged, which were somewhat surprising,” Chan said. “We found that young people have the fastest growing rates of skin cancer, especially young women.
“We were also surprised by how rapidly the mortality rate increased over a 20-year period—an average of eight to nine percent increase per year.”
The study, published Monday in the Canadian Medical Association Journal, found that incidence rates were higher in women younger than 55 and men 55 or older. It also found that rates of non-melanoma skin cancer were rising more rapidly in women aged 45 to 64 than in men in the same age group.
ICES data included adults 18 years of age and older living in Ontario from January 1998 to December 2017. The researchers excluded patients who had a previous keratinocyte carcinoma diagnosis, analyzing only new instances of the disease.
Non-melanoma skin cancer rates decreased in the early part of the study period from 1998 to 2003 and reversed over the remaining 14 years.
The study suggests that the initial period of decline may be due to skin cancer prevention campaigns in the 1980s and 1990s, while a later increase may be linked to the popularity of artificial tanning booths and other practices.
The risk of tanning is highest in younger women and declines with age, Chan said, but women are also more likely than men to have their skin examined, which can lead to an earlier diagnosis.
The Canadian Skin Cancer Foundation states that non-melanoma cancers may present as persistent, non-healing lesions, red spots, shiny bumps or wart-like growths that may occasionally bleed, depending on the type. Is.
Chan said the rising incidence rates and rising mortality rates of non-melanoma skin cancers are worrying.
While the study period ended in 2017, Chan said the pattern “will not have changed” in the four years since then. He said the incidence and death rates could rise if the COVID-19 pandemic hinders early detection and treatment for some people.
“We are seeing patients with larger, more advanced tumors presenting for treatment at a later stage,” he said.
More research and renewed public health efforts are needed to promote preventive behavior and encourage early diagnosis, the study said.
Chan said governments and stakeholders could consider more educational campaigns around sunscreen and protective clothing and urging people to see a doctor if they have “suspected skin lesions.”
“Promoting early detection is important,” he said. “The more advanced the tumor is at the time of diagnosis, the more challenging it is to treat.”