USPSTF simplifies cervical cancer screening recommendations: Dual testing no longer advised

The US Preventive Services Task Force (USPSTF) has issued new draft recommendations for cervical cancer screening with a major change that it recommends either cervical cytology (CC) or high-risk HPV (hrHPV) test as a screening procedure every 3 years for women aged 30-65 years, and not both ( Grade A)  

It still continues to recommend Pap screening every 3 years for women aged 21- 29 years in line with 2012 recommendations (Grade A).

Screening is not recommended in women younger than 21 years because despite their being sexually active, screening in this population subgroup does not reduce cervical cancer incidence or mortality (Grade D).

It also continues to recommend against routine screening for women aged 65 and above who had regularly undergone screening earlier and are not at high risk for cervical cancer and in women who have had a total hysterectomy with no history of cervical intraepithelial neoplasia [CIN] grade 2/3 or cervical cancer (Grade D).

These recommendations do not apply to women with in utero exposure to diethylstilbestrol, or a compromised immune system (living with HIV).

“Cervical cancer is highly curable when found and treated early,” says USPSTF member Carol Mangione, MD, MSPH. “Most cases of cervical cancer occur in women who have not been regularly screened or treated. Therefore, making sure all women are adequately screened and treated is critical to reducing deaths from cervical cancer.”

“The Task Force looked at the evidence on the effectiveness of different screening tests and intervals based on age, and found that after age 30, the Pap test and hrHPV tests are both effective for cervical cancer screening,” says Task Force member Maureen G. Phipps, MD, MPH. “Women ages 30 to 65, therefore, have a choice between the Pap test every three years or hrHPV test every five years.”

The Task Force’s draft recommendation statement and draft evidence review have been posted for public comment on the Task Force website. It is open for public comments from September 12 through October 9, 2017.

 The American Cancer Society (ACS), American Academy of Family Physicians (AAFP), the American Society for Colposcopy and Cervical Pathology (ASCCP), and the American Society for Clinical Pathology (ASCP) recommends similar screening strategy for women aged 21-29 years. 

They defer with USPSTF for age group 30-65 years of age in whom dual screening with cytology and HPV testing is advised every 5 years or cytology alone every 3 years.

ACOG also prefers cotesting with cytology and HPV testing every 5 years but  only cytology every 3 years is acceptable according to a 2016 statement.

USPSTF Draft Recommendation Statement Full Text 

HPV testing vs Pap test in cancer screening: Cochrane Systematic review

A negative HPV test is more reassuring than a negative Pap test, as the cytology screening has a higher chance of being false negative thereby missing some women with precancerous lesions and delaying treatment says the result of a Cochrane Systematic review published ahead of print.

Since decades the usual method of screening for cervical cancer is based on cell cytology, but since the etiological relationship between cervical cancer and HPV infection was confirmed along with advent of HPV testing in 1999, the supremacy of these two tests is debated.

Some physician advice Pap and HPV both, especially for women over 30 years old, who are most at risk of cervical cancer, getting both tests provides the best assurance of finding cervical disease before it becomes cancer.

Younger women (20-30) are advised to get HPV test only if their Pap smear looks "inconclusive" or "borderline.”

This systematic review by Cochrane was aimed at determining efficacy of the two tests in detecting precancerous lesions (CIN 2+ and CIN 3+). Literature search for relevant studies till November 2015 identified about 40 studies amounting to a total of 140,000 women between 20 to 70 years old who underwent cervical cancer screening.

Data analysis identified true positives (TP), false positives (FP), true negatives (TN), and false negatives for each screening test (HPV test and cytology) used in each study.

It was seen that HPV test was more sensitive than conventional Pap test and liquid based test in identifying CIN 2+ and CIN 3+, but less specific than Pap test in detecting precancerous lesion.

Data analysis showed that for every 1000 women screened, around 20 women will have precancerous lesions. If HPV test is used, it will correctly identify 16 of the 20 women to be positive for the lesions (but will miss 4 women who have the lesions). The Pap test will correctly identify 12 of the 20 women (but will miss 8 women).

Similarly, for every 1000 women screened, there will be 980 women who will not have precancerous changes. The HPV test will correctly identify 879 women as disease free (but 101 women will be incorrectly told that they have a lesion). The Pap test will correctly identify 951 women (but 29 will be incorrectly told that they have a lesion).

This high false positive rate of HPV testing will lead to high unnecessary referrals and further tests like colposcopy, biopsy and surgery but at the same time it will also identify 50% more women with precancerous changes as compared to conventional cytology.  

The authors concluded that,” Whilst HPV tests are less likely to miss cases of CIN 2+ and CIN 3+, these tests do lead to more unnecessary referrals. However, a negative HPV test is more reassuring than a negative cytological test, as the cytological test has a greater chance of being falsely negative, which could lead to delays in receiving the appropriate treatment.”

Source: Koliopoulos G, Nyaga VN, Santesso N, Bryant A, Martin-Hirsch PP, Mustafa RA, Schünemann H, Paraskevaidis E, Arbyn M. Cytology versus HPV testing for cervical cancer screening in the general population. Cochrane Database Syst Rev. 2017;8:CD008587. doi: 10.1002/14651858.CD008587.pub2. PMID: 28796882

Access the abstract here.