Mortality attributable to lung cancer is plummeting in Canada, reveal data released Wednesday by the Canadian Cancer Society.
The lung cancer mortality rate has fallen by 3.8% per year since 2015 when we combine men and women, we learn in the Canadian Cancer Statistics 2023 report. The decline is 4.3% per year. year since 2014 for men and 4.1% per year since 2016 for women.
This improvement is mainly attributed to the reduction in commercial tobacco use, which is among the main risk factors for lung cancer. About three in four cases of lung cancer in Canada are caused by smoking.
“When we see that in 1965, nearly 50% of Canadians smoked, while today we are down to 11.6% of the population, we see that we have made significant progress” , commented David Raynaud, who is a senior manager at the Canadian Cancer Society.
Despite everything, lung cancer remains the most prevalent cancer in Canada. It is estimated that 31,000 new diagnoses will be announced this year in the country. Among men, lung cancer mortality rates are generally higher in Quebec and the Atlantic provinces.
“Tobacco control efforts are still needed to further reduce the burden of lung cancer,” the report authors write. There are also concerns that vaping and e-cigarette use increase the risk of lung cancer and, therefore, mortality. »
The Canadian Cancer Society therefore applauds the efforts made by several provinces to regulate the availability of vaping products, particularly with regard to young people.
“We have really made significant efforts in recent years in the fight against smoking, and it would be a shame to have a new generation addicted to nicotine because of this new product,” said Mr. Raynaud.
When we compare with the peak reached in 1988, we see that cancer mortality rates have decreased by 39% among men and by 26% among women, notably thanks to progress made in the fight against lung cancer, the colorectal cancer and other cancers.
Little progress, however, has been made in lowering the mortality rate from pancreatic cancer; cancers of the liver and interhepatic tract also have a low survival rate.
“In general,” the report says, “cancer mortality rates are lower in the Western provinces and Ontario, and higher in Quebec and the Eastern provinces. »
The incidence of colorectal cancer has fallen by 4% in men and 3.1% in women since 2014. The incidence of lung cancer and leukemia has also declined in men, and the incidence of cancer of the thyroid and ovary in women.
On the other hand, melanoma is the form of cancer whose incidence has increased the most among men, with a jump of 2.2% since 1984. Among women, cervical cancer is now the one whose incidence incidence is rising the fastest (+3.7% per year since 2015); This is the first significant increase in the incidence of cervical cancer since 1984.
The number of cancer cases diagnosed each year is increasing, mainly due to population growth and aging. But if we eliminate the effect of age and population size, the risk of cancer decreases.
After lung cancer, bladder cancer, kidney cancer and melanoma are the forms of cancer whose incidence has lost the most ground among men. The same goes for Hodgkin lymphoma, colorectal cancer and melanoma in women.
Importance of screening
The report highlights the importance of early detection in the fight against cancer.
For example, approximately 70% of lung cancer cases are detected at stages III or IV, and less than 16% of people diagnosed at that time will still be alive five years later.
The authors of the report therefore welcome “the planned introduction of lung cancer screening programs in Canada in the near future”, which “could increase early detection of the disease (and) lead to further improvements in survival.”
“People with lung cancer benefit […] treatments that are more precise, more effective, with fewer harmful side effects, said David Raynaud. It’s really important to put the necessary resources in place to detect cancer as quickly as possible because it really makes a difference in survival rates. »
In comparison, mortality rates attributable to colorectal cancer declined significantly for both sexes between 1984 and 2020. Screening programs for this disease detect and remove precancerous polyps, reducing the incidence and helps detect cancer early, when treatment is most effective.
The availability of screening tests varies greatly from one province to another in Canada. In the case of colorectal cancer, for example, Quebec is the only province not to have an organized screening program, but we are hopeful that this will happen soon.
These inequalities then possibly generate differences in net survival by region. Also in the case of colorectal cancer, estimates range from 62% for Nova Scotia to 68% for Newfoundland and Labrador, perhaps reflecting “variations in the stage at which cancers are usually diagnosed in different provinces “.
Despite this, around half of colorectal cancers are diagnosed at stage III or IV, when treatments are less effective.
Ontario currently has the highest five-year survival rate at 64% and the lowest in Nova Scotia at 61%.
The situation in children
About 2% of new cancer diagnoses, or just under 4,000 cases, are predicted to occur in children and young adults (the 0-29 age group).
Among 0-14 year olds, leukemia will represent a third of new cases; Among 15-29 year olds, the three most common new diagnoses will be thyroid cancer, testicular cancer and Hodgkin lymphoma, which together will account for around 40% of new cases.
Eighty-four percent of children diagnosed with cancer were still alive five years later.
The five-year survival rate exceeds 95% in children with Hodgkin lymphoma, nephroblastoma and other non-epithelial kidney tumors, as well as malignant gonadal germ cell tumors. Five-year survival ranges between 65% and 72% for acute myeloid leukemia, rhabdomyosarcomas, intracranial and intraspinal embryonal tumors, malignant bone tumors and hepatic tumors.
Just over 239,000 cancer diagnoses will be announced in Canada this year. It is calculated that 86,700 people will succumb to this disease this year in Canada, and that a quarter of these deaths will be attributable to lung or bronchial cancer.
Cancer remains the leading cause of death in Canada, accounting for 26% of all deaths.