Recent cancer stats reveal conflicting results. Source: Northwestern University

Cancer mortality rates in the United States continue to decline, although the number of actual cancer-related deaths has gone up, according to Cancer Facts and Figures 2008, the American Cancer Society's annual cancer statistics report released Wednesday.

While the report findings might sound like mixed news, ACS experts said progress is being made in the fight against cancer.

The annual statistics report includes estimates of new cancer cases and deaths for the coming year, as well as the most recent cancer mortality data -- in this case, for 2005. The findings, along with detailed state-by-state data on cancer cases and deaths, are published in the March/April issue of CA: A Cancer Journal for Clinicians, and in the standalone Facts and Figures report.

While reports from the last two years have seen declines in the overall number of cancer deaths (in 2003 and 2004), this year's report examining 2005 data shows an increase (559,312 cancer deaths in 2005 compared to 553,888 in 2004).

ACS epidemiologists attribute the rise in part to normal population changes. In 2005, the decrease in death rate was simply not large enough to offset the influence of aging in the population, they said. In addition, there was a smaller decline in the death rate than in previous years. The cancer death rate dropped 1 percent between 2004 and 2005, compared with 2 percent between both 2002 to 2003 and 2003 to 2004.

"The increase in the number of cancer deaths in 2005 after two years of historic declines should not obscure the fact that cancer death rates continue to drop, reflecting the enormous progress that has been made against cancer during the past 15 years," said John R. Seffrin, PhD, ACS CEO. "While in 2005 the rate of decline was not enough to overtake other population factors, the fact remains that cancer mortality rates continue to drop and they're doing so at a rate fast enough that over half a million deaths from cancer were averted between 1990/1991 and 2004."

According to the report, prostate, lung and colorectal cancers account for about half of all cancer diagnoses among men; in women, breast, lung and colorectal cancer make up 50 percent. Cancer incidence rates have more or less steadied since the late 1990s, but certain cancers do appear to be on the decline. Lung cancer incidence rates are down in men and appear to be leveling off in women. There were fewer cases of colorectal cancer in both men and women from 1998 to 2004; female breast cancer incidence rates decreased 3.5 percent per year from 2001 to 2004.

ACS experts estimate that there will be 1,437,180 new cancer cases and 565,650 cancer deaths in 2008.

“The progress that has been made in reducing cancer death rates is a direct result of investment in approaches that we know work, such as comprehensive tobacco control and screening for breast, cervical, and colorectal cancers, as well as research that has identified more successful treatments,” said Otis W. Brawley, MD, chief medical officer of the ACS.

Brawley said that the ACS is also concerned that cancer death rates might increase as more U.S. residents lose health insurance and undergo fewer screenings for the disease.