TORONTO, Canada` - The death toll cancer takes in Canada is on the decline, fuelled in large part by the fact that lung cancer is killing fewer Canadian men than it did in earlier decades, the Canadian Cancer Society said Wednesday.

In its annual report on cancer in Canada, the agency estimated that close to 100,000 lives have been saved in this country over the past 20 years because of the declining cancer death rate.

In part that is due to improved cancer survival rates. There have been advances in treatments for several types of cancer, meaning more Canadians are surviving prostate, breast and colorectal cancer as well as for non-Hodgkin lymphoma, said Gillian Bromfield, the cancer society's director of cancer control policy.

But the biggest factor in the lowering of the death rate is not cancer survival, it's cancer prevention. Fewer men have developed lung cancer in recent years because more men either stopped smoking or never picked up the habit. That trend started decades ago and the benefits are being seen now.

"That has been one of the main drivers in that overall drop in death rates," Bromfield said in an interview. "It's just sort of clear that the overall death rate has really followed the trend in men's lung cancer death rate."

That said, lung cancer is still the No. 1 cancer killer of men and women in Canada. The Cancer Society estimates it kills 37,000 Canadians each year.

"So despite all the progress that we've made in terms of tobacco control and despite seeing decreases in incidence mortality in men, lung cancer still has a huge impact on Canadians. And that's something we hope to change," Bromfield said.

The tide on smoking turned for Canadian men in the 1960s. From a peak of 61 per cent in 1965, the rate of men who smoke dropped to 20 per cent in 2010.

But the trend towards kicking the habit was slower to start among Canadian women. The Canadian Cancer Society said it was another two decades before the smoking rate among Canadian women started to drop in the same way as it had in men. By 2010, only 14 per cent of Canadian women smoked.

The delay means it will be awhile before Canada sees the same type of decline in lung cancer deaths among women that it is seeing among men, said Bromfield, who noted the incidence of the disease in women — the new cases found every year — has started to stabilize.

"So hopefully that means we'll start to see the declines in incidence and therefore the declines in the death rate as well," she said.

Between 1988 and 2007, overall cancer death rates dropped by 21 per cent in men and nine per cent in women.

The cancer society is pushing for more tobacco control measures, hoping to emulate jurisdictions like California where the smoking rates are lower than they are in Canada.

The decline in cancer death rates has been seen elsewhere. Earlier this spring health agencies in the United States reported that death rates there between 2004 and 2008 continued to decline among men, women and children who had been diagnosed with cancer.

Despite the gains, there are concerns among health officials that the rising rates of obesity and inactivity may undo some of the progress attributed to the anti-tobacco campaigns.

"Certainly if we aren't conscious of those risk factors that we know quite well, and those ones that we know for certain contribute to increasing cancer risk, we will see some backsliding even if we continue to make progress in terms of tobacco control," Bromfield warned.

The cancer report estimates that 186,400 new cases of cancer will be diagnosed in Canada in 2012 and 75,700 Canadians will die from the disease. Almost 70 per cent of the new cancer cases will be found in Canadians aged 50 to 79.

Prostate cancer remains the most commonly diagnosed cancer in Canadian men, while breast cancer continues to be the most commonly diagnosed cancer among women.