Annals of Internal Medicine is published by the American College of Physicians on the first and third Tuesday of every month. These highlights are not intended to substitute for articles as sources of information. For a copy of an article, call 215-351-2653 or e-mail Angela Collom at email@example.com
ACP urges adults to get screened starting at age 50
Even though the effectiveness of colorectal cancer screening in reducing deaths is supported by the available evidence, only about 60 percent of American adults aged 50 and older get screened. ACP has released a new guidance statement for colorectal cancer screening recommending that physicians perform an individualized risk assessment for colorectal cancer in all adults. For adults at average risk, physicians should screen for colorectal cancer starting at age 50. For adults at high risk (strong family history, personal history, inflammatory bowel disease) screening should begin 40, or 10 years younger than the age at which the youngest affected relative was diagnosed with colorectal cancer. ACP recommends screening with a stool-based test, flexible sigmoidoscopy, or colonoscopy for average risk adults. Patients at high risk should be screened using colonoscopy. Physicians should select the test based on the benefits and harms of screening tests, availability of the screening test, and patient preferences. The guidance statement does not recommend continued screening for colorectal cancer in adults over the age of 75 or in adults with a life expectancy of less than 10 years because the potential harms of screening outweigh the potential benefits. While colonoscopy is generally regarded as the gold standard to which other screening tests are compared, the risk factors of the test include possible bleeding, perforation of the intestine, and adverse reactions as a result of preparation required for the test. The authors performed a rigorous review of available guidelines to inform the guidance statement.
Mortality rates, not survival rates, determine the success of a screening tool
Cancer screening statistics are usually communicated in the form of improved survival rates. But these data can be misleading, as they are susceptible to lead-time and overdiagnosis biases. For example, a lead-time bias occurs when a group of 67-year-old patients are diagnosed with cancer and die at 70. Their five-year survival rate would be zero percent. If those same patients were screened at age 60, but still died at 70, their five-year survival rate would increase to 100 percent. Nothing changed about who died when, but those screened simply lived longer with a cancer diagnosis. Overdiagnosis similarly skews the data because screening can detect cases of cancer that would never become clinically important during a patient’s lifetime, thus falsely inflating survival statistics. The only reliable evidence that screening saves lives comes from trials that compare cancer death rates (mortality) in groups of people randomly assigned to screening or no screening. Mortality statistics are not affected by lead-time or overdiagnosis biases. But a national survey of 412 primary care physicians suggest that doctors do not understand which statistics provide evidence about whether screening saves lives. Researchers found that physicians were more enthusiastic about a screening test supported by irrelevant evidence (survival rates) than tests supported by relevant evidence (reduced mortality). When presented with irrelevant evidence, 69 percent of physicians recommended the test compared with 23 percent when presented with relevant evidence. Even a note explaining the biases did not change the physicians’ answers. The researchers and an editorialist, Dr. Virginia Moyer, Chair of the US Preventive services Task Force, conclude that this study shows that physicians need to be better educated about how to interpret studies about cancer screening tests. According to Dr. Moyer, what physicians don’t know can hurt their patients.
Surrogates who make decisions regarding life support for incapacitated patients need to have a clear understanding of not only the patient’s values and goals, but also the likely outcomes of treatment. Researchers surveyed 80 surrogates of critically ill patients to determine how they interpret prognostic statements and to explore factors influencing surrogates’ interpretations of grim prognostic information. Using a questionnaire, the surrogates were asked to use a probability scale to interpret 16 prognostic statements. The researchers found that when prognosis was good (low risk for death), surrogates’ interpretations were reasonably accurate. However, when the prognosis was negative (such as “a five percent chance of surviving”), surrogates tended to be more optimistic about how the patient would do than the prognosis information indicated. According to the researchers, the qualitative portion of the survey revealed a potential source for the bias, unrelated to the surrogates’ understanding of medical terminology or numeric statements. Surrogates expressed a strong need to show optimism when a patient was at high risk for death. The surrogates also believed that their loved one had positive attributes that would cause him or her to “outperform physicians’ grim prognostications.” The researchers conclude that clinicians need to develop communication strategies that address the emotional and cognitive biases that arise in surrogate decision making.
The availability of potent antiretroviral therapy (ART) has resulted in remarkable decreases in HIV-related morbidity and mortality in the last 15 years. However, recent data from the U.S. Centers for Disease Control and Prevention reveal that only 28 percent of persons with HIV in the U.S. have achieved viral suppression on ART. Of those who knew they had HIV, only 69 percent were linked to care, and only 59 percent were retained in care. The International Association of Physicians in AIDS Care (IAPAC) convened a panel to develop evidence-based guidelines to optimize entry into, retention in care, and ART adherence for people with HIV. Researchers reviewed 325 published studies to form the basis of the recommendations. Based on the evidence, the researchers developed five recommendations specific to entry into and retention in HIV medical care, and five recommendations related to monitoring ART adherence. Recommendations related to interventions to improve ART adherence were divided into several subcategories: ART Strategies (regimen-specific recommendations); Adherence Tools for Patients; Education and Counseling Interventions; and Health System and Service Delivery Interventions. The guidelines also included considerations for special populations including pregnant women, patients with substance use disorders or mental health disorders; incarcerated individuals; the homeless; and children and adolescents.