Cancer death rates continue to decline in the United States, mainly because anti-smoking efforts have caused a drop in lung cancer deaths, researchers report.
From 2001 through 2010, death rates for all cancers combined decreased by 1.8 percent a year among men and by 1.4 percent a year among women, according to a joint report from four of the nation's top cancer institutions, published Dec. 16 in the journal Cancer.
"The four major cancers -- lung, colorectal, breast and prostate -- represent over two-thirds of the decline," said study author Brenda Edwards, a senior advisor for cancer surveillance at the U.S. National Cancer Institute.
The report also found that one-third of cancer patients over 65 have other health conditions that can lower their chances of survival. Diabetes, chronic obstructive pulmonary disease (COPD), congestive heart failure and cerebrovascular disease, which impedes blood flow to the brain, are the most common ailments that complicate cancer treatment and survival odds, the researchers said.
"It's good to see a report of this prominence focus on this," said Dr. Tomasz Beer, deputy director of the Knight Cancer Institute at Oregon Health & Science University. "The general health of patients is important, and it impacts on cancer outcomes."
The report produced by the National Cancer Institute, the American Cancer Society, the U.S. Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries.
Researchers found that lung cancer death rates for men fell by 2.9 percent a year between 2005 and 2010, a much faster rate than the 1.9 percent-per-year decline during the period 1993 to 2005. \
For women, rates declined 1.4 percent annually from 2004 to 2010, which was a turnaround from an increase of 0.3 percent a year during the period 1995 to 2004.
The researchers attributed these overall decreases to the decline in cigarette smoking in the United States. Since lung cancer accounts for more than one in four cancer deaths, these declines are fueling the overall reduction in cancer deaths.
Beer said new targeted therapies for lung cancer have also helped improve survival chances. He expects lung cancer death rates to fall even further with the advent of new standards for lung cancer screening using low-dose CT scans.
"I was particularly struck by the overall decline in cancer death rates," Beer said of the study. "It's modest but real, and the fact that it's annual is encouraging in the sense that even though these gains are modest, they compound over time."
Death rates among men decreased for 11 of the 17 most common cancers, increasing only for melanoma, soft tissue cancers and cancers of the pancreas and liver. Death rates among women decreased for 15 of the 18 most common cancers, increasing for cancers of the uterus, pancreas and liver.
Researchers compared National Cancer Institute data with Medicare claims data to investigate other health problems that can complicate cancer treatment and survival.
Diabetes and its associated complications is the most common health problem affecting cancer patients. It was found in 16 percent of people older than 65 diagnosed with cancer between 1992 and 2005, the researchers said.
"There are a number of issues with diabetes," Beer said. "Some data even suggests insulin can accelerate the growth of cancer." (Many diabetics take insulin, a hormone needed to turn food into fuel for the body).
Patients with diabetes also have to struggle with the effect that cancer medications can have on their blood sugar, Beer added. They may end up receiving a lower dosage or stopping a treatment regimen early because of the conflict between their diabetes control and their cancer therapy.
COPD affects more than 15 percent of older cancer patients, while congestive heart failure affects about 10 percent of patients. About 6 percent are affected by cerebrovascular disease, which can include stroke and aneurysms.
Lung and colorectal cancer patients tended to have other health problems more often than people with other cancers. People with breast and prostate cancers tended to have other health problems at the same rate as people without any cancer.
"The general strength and wellness of patients makes a huge difference in cancer outcomes," Beer said. "People who are capable of going on a hike, jogging, running and eating healthy do a heck of a lot better than people who are sedentary and in poor physical condition."
