A substantial proportion of older adults in the United States undergo unnecessary and even harmful screening for colon, prostate, breast, and cervical cancer, contrary to clear guidelines that are widely recognized and well publicized, according to two separate studies published online Aug. 18 in JAMA Internal Medicine.
In the case of colon cancer, most of these unnecessary screenings can be attributed to patients getting rescreened more frequently than at the 10-year intervals recommended and continued screening past the age of 75 years is also a culprit. With the other cancers, the main reason for these unnecessary procedures is continuing screening in patients who have a short life expectancy because of advanced age or irreversible health problems.
Dr. Trevor Royce
In both reports, the investigators emphasized that unnecessary cancer screening is not only inefficient and expensive from a societal perspective but is also harmful for individual patients because it exposes them to invasive procedures and complications, impairs their quality of life, and sometimes leads to downstream overdiagnosis and overtreatment of cancers that would have remained asymptomatic until the patient died of other causes.
In one of the studies, researchers analyzed data from the population-based National Health Interview Survey, which assesses approximately 90,000 Americans each year to provide health information representative of the U.S. population. They focused on 27,404 participants aged 65 years and older who reported on the cancer screening they underwent between 2000 and 2010. A validated mortality index was used to calculate each respondent’s 9-year mortality risk based on factors such as age, sex, smoking status, body mass index, comorbidities, hospitalizations, and functional measures, said Dr. Trevor J. Royce of the departments of radiation oncology and medicine, University of North Carolina at Chapel Hill, and his associates.
They found that contrary to numerous recommendations, "a sizable proportion of the U.S. population who have less than a 9-year life expectancy" underwent screening for cancer, including 55% of men who were screened for prostate cancer, 41% of people screened for colorectal cancer, 38% of women screened for breast cancer, and 31% of women screened for cervical cancer.
Most egregiously, as many as 56% of women who had undergone hysterectomy for benign reasons were still undergoing annual Pap tests to detect cervical cancer, even though most of them no longer had a cervix. And overscreening for prostate cancer was especially common, "possibly because PSA testing is viewed as a simple, safe blood test, with little recognition of the important downstream harms," Dr. Royce and his associates said (JAMA Intern. Med. 2014 Aug. 18 [doi:10.1001/jamainternmed.2014.3895]).
Cancer screening was also common in people whose life expectancy was less than 5 years, or even less than 3 years. Even though the lack of net benefit from cancer screening in such patients "is widely recognized and publicized in clinical practice guidelines, important obstacles exist to reliably applying these guidelines."
Chief among these obstacles is the lack of a simple, reliable tool for assessing life expectancy in clinical practice. In addition, physicians may find it difficult to communicate to patients that they are very likely to die within the next few years, and patients may find it difficult to accept that they have a limited life expectancy or that cancer screening is no longer warranted for them. Physicians’ fear of litigation further contributes to overscreening, Dr. Royce and his associates said.
In the other study, researchers used microsimulation modeling to assess whether screening more intensively than recommended for colorectal cancer would be favorable for individual patients or for society as a whole. They created two hypothetical cohorts of 10 million Medicare beneficiaries at average risk for the disease: the first included patients who had a negative screening colonoscopy at age 55 years and the second included patients who had never been screened for colorectal cancer, said Dr. Frank van Hees of the department of public health, Erasmus University Medical Center, Rotterdam, the Netherlands, and his associates.
The model simulated recommended screening (that is, colonoscopy at ages 65 and 75 years), as well as several shorter screening intervals, screening up to age 85 years, and screening up to age 95 years. It factored into the analyses the sensitivity rates for colonoscopy for adenomas or carcinomas at various stages, age-specific risks for GI and cardiovascular complications requiring hospitalization, and survival rates after a variety of possible clinical diagnoses. "For each scenario of more intensive screening than recommended, we determined the associated increase in colorectal cancer cases prevented, colorectal cancer deaths prevented, life-years gained, life-years with cancer care prevented, colonoscopies performed, and complications experienced," the investigators said.