Death rates for the four major cancers — lung, colorectal, breast and prostate — are declining, thanks to falling smoking rates and increases in screening and treatment, the Canadian Cancer Society says.

Wednesday's annual report on cancer statistics showed that between 1988 and 2007, nearly 100,000 lives have been saved. Over that time span, overall cancer death rates dropped by 21 per cent in men and by nine per cent in women.

The society said the gender gap was because smoking rates among men started to decline in the 1960s but women’s smoking rates did not begin to decrease until the 1980s. There's a time lag before a decline in smoking prevalence translates into drops in lung cancer incidence and death rates.

"We've seen a big drop in the death rates due to lung cancer in men only," Gillian Bromfield, the group's director of cancer control policy, said in an interview. "So that has been one of the main drivers that has had actually a huge impact on the overall cancer death rate in Canada."

About half of cancers can be prevented, said Bromfield. The society advocates for governments to pass policies "to make healthy choices easy choices," she said.

Tobacco use, along with unhealthy eating habits, physical inactivity, excess body weight, alcohol consumption, overexposure to the sun, and exposure to environmental and workplace carcinogens account for a "substantial number" of cancer diagnoses and deaths each year, the group said.

About 27 per cent of all cancer deaths are attributed to lung cancer, and the disease is the leading cause of cancer death among women. More Canadians die of lung cancer every year than the combined deaths from breast, colorectal and prostate cancer.

The declines in death rates for other cancers suggested improvements in screening, such as the fecal occult blood test for colorectal cancer, Pap test for cervical cancer and improvements in type and uptake of screening for breast cancer, are paying off, the group said.

Stamping out smoking

"The trends call for an enhancement of primary prevention efforts; a sustained focus on screening for breast, colorectal and cervical cancers; more emphasis on early detection measures and public education on the early signs of cancer; and improved treatment options and health promotion," the report's authors concluded.

Health officials want the progress of anti-tobacco campaigns to continue to drive down smoking rates as fast as possible.

"We still have a ways to go in terms of developing high quality preventive and cessation programs," said Heather Bryant, vice-president of cancer control for the Canadian Partnership Against Cancer.

The partnership is following a large number of Canadians with questionnaires to look at the interaction between behaviour and genetic make-up in cancer and chronic disease.

Margie Douglass of Halifax smoked since she was 13. She started trying to quit using gum, patches, acupuncture and hypnosis.

Douglass is now participating in the provincial lung association's program that encourages people to develop the healthy habit of runnning instead of smoking.

"This is the best I've ever felt since I was 23 that first time trying to quit," said Douglass, who is currently smoke-free.

Rare cancer incidence rises

Along with the declines, the incidence of rare cancers, such as liver, thyroid and kidney, are on the rise.

Obesity is thought to be driving up both liver and kidney cancers. Immigration from countries where hepatitis B and C virus infections are more common, as well as alcohol abuse, contribute to liver cancer.

Thyroid cancer is the most rapidly increasing cancer. More frequent use of diagnostic testing that may be detecting earlier stage, asymptomatic thyroid cancers could be behind the higher incidence, the society said.

An estimated 186,400 new cases of cancer will be diagnosed in Canada this year and an estimated 75,700 people will die from the malignancy.

The report was released with the Public Health Agency of Canada and Statistics Canada.

With files from CBC's Kelly Crowe and Pauline Dakin