WASHINGTON (EGMN) - There have been some significant victories in the almost 40 years since President Richard M. Nixon signed the National Cancer Act in 1971, declaring the "war on cancer," according to commentary offered by American Cancer Society epidemiologists at a March 16 briefing sponsored by the Journal of the American Medical Association.
Even so, despite more than $100 billion spent by the United States government alone over those years, cancer is still the second-leading cause of death in the United States and, by the end of this year, is projected to be the leading cause of death worldwide.
Susan M. Gapstur, Ph.D., vice president at the ACS presented an overview of the progress in the war so far at the briefing. Her commentary, which was co-authored with Dr. Michael J. Thun of the ACS, appears in the March 17issue of JAMA.
Claims of defeat or stasis in the war are inaccurate, given surveillance reports that show an almost 16% decrease in the death rate from all cancers combined between 1991 and 2006, said Dr. Gapstur. There has been a 1% annual drop in the incidence rate between 1999 and 2006, she noted in her paper.
Mortality rates for men have dropped 21% since their peak in 1990, and mortality rates for women have dropped 12% since their peak in 1991, she said. The overall drop in death rates since 1970 has been about 6%.
The ACS estimates that some 765,000 cancer deaths have been avoided since 1990.
But the decline in mortality is more impressive when taken into context, she said. Since 1970, the U.S. population has grown 30%, and there has been a twofold increase in adults aged 55 years or older. That segment of the population accounts for three-quarters of the cancer incidence.
Incidence rates and the sheer number of people dying from cancer are expected to rise with the aging of the U.S. population. During their lifetime, one in two men and one in three women will be diagnosed with cancer.
The ACS estimates that there were 1.5 million new diagnoses in 2009 and 560,000 deaths.
The billions of dollars spent on public and private research has helped determine that cancer is incredibly variable and individualized. There are more than 100 different anatomical and histological subtypes of the disease. Many of these illnesses have "multiple molecular variants with different [prognoses], clinical features, and susceptibility to treatment," wrote Dr. Gapstur and Dr. Thun.
There have been successes, chief among them the decline in cigarette smoking that has led to a 40% reduction in cancer mortality for men from the peak rates, largely due to a huge decline in lung cancer deaths.
Early detection through Papanicolaou testing has also reduced the death rate from cervical cancer. Screening technologies hold the same promise for breast and colon cancer, and to a more debatable extent, prostate cancer, according to the authors (JAMA 2010;303:1084-85).
Treatment advances have led to more success stories in pediatric cancers. Dr. Gapstur noted that some 80% of pediatric cancer patients survive 5 years or more. Therapeutic advances have also led to better prognoses for Hodgkin's disease, testicular cancer, and chronic myelogenous leukemia, they said.
Localized cancers also are being treated with greater success, leading to better prognoses. But metastatic cancers and certain, more lethal diseases, such as cancers of the brain, liver, lung, ovary, and pancreas, are still a "critical problem," the authors wrote.
Death rates are rising for esophageal and liver cancer and melanoma in men, and for pancreatic and liver cancer in women. These cancers may be obesity related, said Dr. Gapstur, who noted that the obesity epidemic could fuel rising cancer death rates in the future.