Significant reduction in cancer death toll

The problem in tabulating the full extent of recent gains against cancer is that efforts to beat back other diseases have also been successful, the researchers said.

"As fewer and fewer people die from heart disease, stroke and accidents, more and more people are alive long enough to be at risk of developing and dying from cancer," study principal investigator Samir Soneji, an assistant professor at the Geisel School of Medicine at Dartmouth College, said in a statement provided by Dartmouth-Hitchcock Medical Centre.

For example, the study found that deaths from heart disease declined by 62% between 1970 and 2008. During the same period, deaths from accidents fell by more than a third.

Risk increases with age

Deaths from cancer, however, dipped by only 12%, the researchers said.

As part of their research, Soneji's team accounted for progress against cancer in the context of people avoiding other illnesses or accidents and living longer. Cancer risk increases with advancing age, making it more likely that today's longer-lived Americans will someday develop the disease, the researchers said.

"We estimate how the years of life lost from cancer are directly affected by cancer mortality and indirectly affected by increased cancer incidence because of greater longevity due to improvements in primary prevention, detection and treatment of other diseases," Soneji said.

In this context, the researchers found signs of significant progress in cutting cancer death rates.

Quitting smoking

For example, lung cancer deaths dropped dramatically between 1985 and 2005, mainly due to people quitting smoking, Soneji said. But the decline in these deaths wasn't as great as it could have been because more people were avoiding death from other causes – and living long enough to develop lung cancer.

Overall progress in limiting deaths from colon, prostate and breast cancers has also been seen, the researchers said.

"Our approach reveals more accurately the aggregate contribution of cancer prevention, screening and treatment on progress against cancer," Soneji said.

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