Lung cancer higher in the region than in the rest of the province

Saguenay–Lac-Saint-Jean Public Health held a technical briefing on Wednesday on the portrait of lung cancer in the region, similar to what it organized last year on the portrait of cancer. in general. Lung cancer is the most common cancer. It represents 18% of cases, all cancers combined, but 30% of all cancer deaths.

“It is estimated that one in 14 people will one day have lung cancer in Quebec,” mentions Dr. Martin Fortin, public health physician advisor, who participated in producing the portrait.

Doubling of lung cancers

In the region, the number of cancers has doubled in nearly 30 years, going from an annual average of 218 cases for the period from 1986 to 1990, to an average of 413 cases between 2016 and 2020. Of these 413 cases, we records, on average, 249 annual deaths. These rates can be explained in particular by the aging of the population, which is more significant in Saguenay–Lac-Saint-Jean than in other regions.

This is why scientists prefer to calculate the standardized incidence rate, which will take into account the number of lung cancers according to the age group, and will thus make it possible to compare with other regions. We then notice that the cancer rate according to age group has tended to decrease since the 1980s in the region, to reach the provincial rate, but still remains higher than in other regions.


Doctor Martin Fortin, medical advisor to Public Health. (Sophie Lavoie/Le Quotidien)

On the other hand, the standardized mortality rate decreased in Saguenay for the most recent period. Although lung cancer generally occurs in adults over the age of 40, it is people aged 70 and over who account for the highest incidence and mortality rates in the region. The local health networks (RLS) of Jonquière and Domaine-du-Roy show significantly higher rates than the rest of Quebec.

Dr. Martin Fortin also highlights that the standardized incidence rate among women has increased, unlike that of men, which is experiencing a downward trend. Despite everything, this cancer rate by age group among women remains lower than that of men.

“The smoking rate was much higher among men compared to women, and the fact that men started quitting before women. We have had a delay among women in starting to stop smoking, they are more numerous than men and are getting older,” he explains.


(Sophie Lavoie/Le Quotidien)

Risk factors

“It is estimated that 86% of lung cancers are attributable to modifiable factors. »

— Dr Martin Fortin

There are different risk factors that can cause lung cancer, starting with the first in line, the big champion: smoking, which alone represents nearly 72% of cases, even if the number of adult smokers fell from 30% in the 2000s to 16% in 2018.

Thanks to changes made in health policies, interventions by Public Health and various doctors and nurses, smoking has been steadily decreasing in recent years.

“When we talk about the risk of lung cancer linked to tobacco, we have to talk about the latency period; it takes several years of exposure to eventually develop lung cancer. What we measure today is the result of what happened 20-30-40 years ago.”

— Dr Martin Fortin

Exposure to radon is described as being the second factor, after tobacco, responsible for 7% of lung cancers. Atmospheric pollution and poor air quality would also be aggravating factors.

>>>Regional Public Health presented a portrait of lung cancer on Wednesday. From left to right: Dr. Martin Fortin, Dr. Donald Aubin and Dr. Jean-François Betala, doctor specializing in community health.>>>

Regional Public Health presented a portrait of lung cancer on Wednesday. From left to right: Dr. Martin Fortin, Dr. Donald Aubin and Dr. Jean-François Betala, doctor specializing in community health. (Sophie Lavoie/Le Quotidien)

Physical inactivity (up to 11%) and a diet low in fruits and vegetables (between 2 and 6%) can also influence the emergence of lung cancer.

Finally, some workers are exposed in the workplace to substances such as asbestos, polycyclic aromatic hydrocarbons (PAHs), diesel engine exhaust, crystalline silica, nickel, chromium, radon, and second-hand smoke. Dr. Fortin estimates that these occupational exposures represent 45 cases in Saguenay, or 2% of the total number of lung cancers in the region.

These risk factors linked to lifestyle habits are said to be modifiable, but there are also other non-modifiable risk factors, such as family history, genetic mutations, a deficient immune system, ethnic origin, or another previous lung disease.

But socioeconomic inequalities can also come into play. Indeed, researchers have discovered a gradient that disadvantages people with low income or little education.

Vaping and cannabis

>>>The effects of vaping on lung cancer are not yet known, but could provide surprises in the future.>>>

The effects of vaping on lung cancer are not yet known, but could provide surprises in the future. (Archives)

The long-term effect of vaping has not yet been studied. According to scientists, it is possible that the carcinogenic effect is less than for cigarettes, because the chemical composition is different, but this still remains to be demonstrated. Same observation for cannabis.

“We know that when we switch from cigarettes to vaping, we are more likely to return to cigarettes and we know that there is a lot of common element in the combustion products between cigarettes and vaping. The risk of cancer could decrease with vaping, but it could also be that it doesn’t change either. It will take several years before we see results,” says Dr. Fortin.

To continue to reduce the number of cases of cancer, we should continue the fight against smoking, improve food security, develop infrastructure for active travel, promote physical activity and leisure even more, reduce social inequalities of health, and adopt policies for better air quality to reduce health risks.



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