A new evidence report recommends that annual Papanicolaou (Pap) screening be stopped, since many women are being tested too frequently, possibly leading to overtreatment of low-grade lesions that might not prove to be cancerous.

Researchers at the US Preventive Services Task Force (USPSTF; Rockville, MD, USA) reviewed the evidence on liquid-based cytology (LBC) and high-risk human papillomavirus (HPV) screening, using data from MEDLINE, the Cochrane Central Register of Controlled Trials, and PsycINFO from January 2000 through September 2010. Two independent reviewers then selected fair- to good-quality English-language studies that compared LBC or HPV-enhanced primary screening with conventional cytology, in countries with developed population-based screening for cervical cancer.

The review found no direct evidence that annual screening achieves better outcomes than screening every three years. Modeling studies suggest little added benefit of more frequent screening for most women. In addition, too frequent screening can result in increases in cost and in women having needless anxiety due to false positive results. The task force also recommended that screening begin for all women at age 21, regardless of their sexual activity levels, reflecting a change from the task force's 2003 recommendation stating that screening should begin at age 21 or within three years of the initiation of sexual activity.

The task force also reported that there is little evidence supporting continuation of screening for women older than 65 if their recent Pap smears have been normal, and they are not at risk for cervical cancer. Similarly, screening is unnecessary in women who have had a hysterectomy for benign disease. They cautioned that clinicians should confirm through surgical records or inspecting for absence of a cervix that a total hysterectomy was performed, and that screening may be appropriate when the indications for hysterectomy are uncertain. The task force also emphasized that more efforts should be made to identify and reach out to women who have not undergone screening. The evidence report was published in the October 18, 2011, issue of Annals of Internal Medicine.

“Although there is little value in screening women who have never been sexually active, many US organizations recommend routine screening by age 18 or 21 for all women, based on the generally high prevalence of sexual activity by that age in the US and concerns that clinicians may not always obtain accurate sexual histories,” concluded lead author Evelyn Whitlock, MD, MPH, and colleagues of the USPSTF.

As for screening methodology, the recommendations stated that newer technologies, such as liquid-based cytology, may have improved sensitivity over conventional Pap smear screening, but at a considerably higher cost and possibly with lower specificity. In the absence of studies that address cervical cancer outcomes, the task force found that available data on the accuracy of new technologies were insufficient to determine whether they are more effective than conventional cervical cytology for preventing invasive cervical cancer.

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