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The October 18 issue of Annals includes two articles on mammography screening and two articles on cervical cancer screening. The following press releases summarize the findings in both topic areas.
Author: By knowing what to expect, women may experience less anxiety related to screening
Mammography screening has been shown to reduce deaths from breast cancer, but controversy remains about the best time to begin screening and how often to get screened. In 2009, the U.S. Preventative Services Task Force recommended that the decision to start regular mammography before the age of 50 years should be an individual one and that physicians should take patient context into account, including the patient's values regarding specific benefits and harms. The Task Force also recommended that women aged 50 to 74 years and younger women who opted for screening should have screening once every two years versus every year.
A potential harm of shorter interval breast cancer screening is the risk of false-positive results. To compare the cumulative probability of false-positive results and stage of cancer diagnosis after 10 years of screening with either an annual or a biennial schedule, researchers studied seven mammography registries in the Breast Cancer Surveillance Consortium, the most comprehensive breast cancer registry in the world. The researchers concluded that after 10 years of annual screening, more than half of women will have at least one false-positive recall, and 7 to 9 percent will have a false-positive biopsy recommendation. Biennial screening reduces false-positive recalls by about one-third, but is associated with a small increase in the probability of late-stage cancer diagnosis.
Using data from the same registry, researchers studied screening records for women aged 40 to 79 who underwent digital (n=213,034) versus film-screen mammography (n=638,252) to determine if one method was better than the other at detecting cancer. The researchers found that digital and film-screen mammography were equally effective for women age 50 to 79, but for women age 40 to 49—especially those with dense breasts—digital was a bit more likely to find a cancer. However there was also had an increased risk for false positive results for these younger women.
“We conducted these studies to help women understand that having a false positive result is part of the process for mammography screening,” said Rebecca Hubbard, PhD, Assistant Investigator at Group Health Center for Health Studies, Seattle, WA, and co-author of both studies. “We hope that by helping women know what to expect in terms of false-positive results, they’ll be less likely to experience anxiety when they are called back for a repeat screening or biopsy.”
The study authors recommend that women and their doctors develop a screening plan based on the patient’s individual risk factors for breast cancer, and tolerance for false-positive recalls.
Evidence will inform upcoming update of 2003 screening recommendations
In 2003 the U.S. Preventive Services Task Force (USPSTF) published recommendations for cervical cancer screening. To inform an updated recommendation, researchers performed two reviews of the published literature focusing on evidence that has become available since the 2003 recommendation.
The first article reviewed published articles comparing liquid-based cytology to the conventional Pap smear. With a conventional Pap smear, the clinician collects cells from a woman’s cervix and transfers them to a slide for microscopic evaluation. With a liquid-based test, cervical cells are preserved in fluid, rather than smeared directly onto a slide. The same sample can be used for HPV testing.
The researchers found that conventional and liquid-based pap tests did not differ substantially in measures of relative detection or absolute sensitivity or specificity for detection of precancerous cells. However, the liquid-based test produced fewer unsatisfactory slides than conventional testing. Available evidence, though minimal, suggested no substantial difference in harms between the two tests.
Researchers also reviewed published research to assess the benefit and harms of HPV testing in women 30 years and older as an alternative or adjunct to conventional cytology screening. They found that HPV testing was more sensitive than cytology, but there was reduced specificity. While HPV-enhanced screening strategies offer a potential cancer prevention benefit compared with Pap testing alone, there is insufficient evidence to justify substituting HPV for cytology at the population level.
In terms of HPV-screening harms, false positive screening results and diagnosis of regressive or non-progressive histologic pre-disease could result in harms from unnecessary procedures or overtreatment. In addition, women diagnosed with HPV (especially young women for whom the disease may clear on its own) may experience unnecessary anxiety. At this time, researchers need more evidence in order to understand the population impact of HPV testing as a cervical cancer screening tool.
A second review focused on the appropriate ages at which to begin and end cervical cancer screening. Because cervical cancer is rare among women under the age of 20, the research supports beginning screening at age 21. If a woman aged 65 or older has had adequate recent screening with normal Pap smear result and is not at otherwise high risk for cervical cancer, the research suggests that she can end screening age 65.
The evidence reviews have been used to develop a draft recommendation statement that will be posted to the USPSTF website for public comment on October 19th. The final recommendation will be published in Annals at a later date.
Opinion piece co-authored by renown author, Abraham Verghese, MD
In the first half of the 20th century, the bedside evaluation (the act of taking a patient’s health history and performing a physical examination) was the most important means of diagnosis. Today, the bedside evaluation has largely been replaced by the use of sophisticated imaging and laboratory testing. Technological advances have improved patient care, but possibly at the cost of the bedside evaluation. Some physicians worry that the lack of bedside evaluation skills could lead to errors in diagnosis and subject the patient unnecessary testing. For patients, the bedside evaluation serves an important psychological function. The patient expects to examined in a skilled, respectful, and ritualized fashion. When this expectation is met, it brings about a positive therapeutic effect. According to the authors, the ritual is as important as the evaluation itself. The ritual includes the use of physician tools (stethoscope, reflex hammer), medical terminology (fremitus, tenderness), and special settings and garments (examination table, white coat). Because of its potential to enhance patient care, the bedside evaluation should be used in conjunction with technology as a regular part of treatment. According to the authors, the bedside evaluation is a ritual worthy of teaching, testing, refining, and preserving.