A new study found that breast cancer is rapidly rising in younger Canadians. The researchers suspect that a heavier population may be at fault.
The study released on Wednesday at JAMA Network Open looked at data from all Canadians diagnosed with colorectal cancer between 1969 and 2016.
The researchers found that the risk of colorectal cancer in the youngest cohort of men (those aged 20 to 29 in 2015) was more than twice the risk of that age group in 1936. For women, the incidence rate was also higher high in younger cohorts, although the difference was not considered significant.
Rates of the disease among Canadians below 50 have been steadily rising since the mid-1990s, while rates have dropped mostly for those over 50 since the 1980s, according to the paper.
International studies have found a similar pattern. A study published in The Lancet earlier this year looked at rates among 143 million people in Australia, Canada, Denmark, Norway, New Zealand, Ireland, and the United Kingdom. but increased. dramatically between 50 years old.
The authors of the new study, led by Dr. Darren Brenner of the University of Calgary, say that increasing colonoscopies for purposes other than cancer cannot explain most new cases. "
"More likely, lifestyle factors associated with increased weight gain are fueling the increase in (colorectal cancer) incidence in this age group," the authors write.
The paper concludes that more research is needed to decide if project recommendations should change.
The Canadian Gastroenterology Association recommends that people whose parents, children or siblings have been diagnosed with breast cancer should be screened between the ages of 40 and 50, or 10 years earlier than the age at which their relative was diagnosed.
The Canadian Prevention Health Task Force recommends screening every two years for those aged 50 to 74 years.
People of all ages are encouraged to watch for changes in the bowel movements, signs of straight blood or shells in their abdomen, which could be signs of the disease.
The authors of the new study write that although younger screening may reduce mortality, guidelines need to consider potential negative consequences of screening including the invasive nature of colonoscopies and possible increased waiting times for individuals at higher risk.
Colorectal cancer refers to both colon and rectal cancers. In 2017, an estimated 26,800 Canadians were diagnosed with the disease, according to the Canadian Cancer Society. The five-year survival rate is estimated at 63 percent for men and 65 percent for women.