Many older Americans are unnecessarily screened for breast and prostate cancer, which can lead to treatments they don't need, a new study contends.
The practice may also be costing the U.S. health care system $1.2 billion a year, the researchers added.
Almost 16 percent of those 65 and older are being screened for breast or prostate cancer even though they may have less than 10 years to live, the study found. A 10-year life expectancy is a benchmark for deciding whether to screen or not. And guidelines recommend against screening for these cancers in people with a life expectancy less than 10 years, the researchers said.
"Physicians, as well as patients, should consider life expectancy when deciding the necessity of prostate cancer or breast cancer screening," said lead researcher Dr. Firas Abdollah, of the Henry Ford Health System in Detroit.
"To achieve this goal, we need to overcome many hurdles," he said, which include the lack of easy-to-use and accurate life expectancy calculators to guide doctors in making screening recommendations.
Also, busy doctors may find it hard to explain the concept of life expectancy and why screening is not recommended for certain individuals, he added.
Robert Smith, vice president for cancer screening at the American Cancer Society, said: "This can be a hard conversation for doctors to have with patients. If a patient shows some enthusiasm for getting these tests, it's just easier to do the test than it is to have that conversation, especially if you're not that good at doing it."
In addition, it's difficult to estimate whether somebody has 10 years to live, Smith said.
The report was published online Jan. 21 in the journal JAMA Oncology.
Smith said that the U.S. Preventive Services Task Force recommends mammograms for women up to age 74. The task force does not recommend screening for prostate cancer at all, he said.
Using 10-year longevity as a benchmark for screening is the American Cancer Society's guideline, Smith said.
"We recommend that men should not be offered prostate cancer screening if they don't have 10 years of life left," he said. "Our breast cancer guideline is the same."
Abdollah said cancer screening aims to detect tumors early, before symptoms appear. "Evidence suggests that detection and treatment of early stage tumors may reduce cancer mortality among screened individuals," he said.
Despite this benefit, screening may also cause harm, he said. Screening may identify low-risk tumors that would never become life-threatening, but subject patients to the harms of unnecessary treatment, such as side effects of therapy and a reduced quality of life, he added.
For the report, Abdollah and his colleagues collected data on nearly 150,000 people 65 and older who responded to the Behavioral Risk Factors Surveillance System survey in 2012.
Among these people, 51 percent had had a prostate-specific antigen (PSA) test or mammography in the past year. Of those who were screened, almost 31 percent had a life expectancy of less than 10 years. The rate of non-recommended screening was 15.7 percent, Abdollah said.
This rate varied across the country, from 11.6 percent in Colorado to just over 20 percent in Georgia, the researchers found. States with a high rate of non-recommended screening for prostate cancer also had a high rate of non-recommended screening for breast cancer.
Smith said the other side of the coin is that many doctors fail to recommend screening for patients who clearly have 10 years to live or more.
About one-third of women who die from breast cancer each year are over 70, Smith said. "That means there is a significant fraction of these deaths that could be avoided if women had been screened," he said.
Smith added that many doctors aren't aware of the tools available to predict longevity and many who are aware don't use them. "Doctors need to be better prepared to estimate longevity, and have conversations with patients about cancer screening," he said.
Smith did note that as patients get older they tend to lose interest in screening.
"There is a natural attrition as you get older -- patients lose interest in prevention and doctors become preoccupied with managing life-limiting conditions," he explained.