Cervical screening is shifting from the Pap smear to the HPV test

For decades, cervical screening meant one thing: the Pap smear, a sample of cervical cells examined under a microscope for early changes. It worked — deaths from cervical cancer in the United States fell from 2.8 to 2.3 per 100,000 women between 2000 and 2015 as screening became widespread [s1]. But the test at the centre of the programme is changing, from looking at cells to looking for the virus that causes almost all cervical cancer. The transition is well underway, and the major guidelines do not fully agree on how fast to make it.

What the guidelines currently allow

The US Preventive Services Task Force recommends screening women aged 21 to 65 [s1]. For women aged 21 to 29, it recommends cytology — the Pap test — every three years. For women aged 30 to 65, it offers three equally endorsed options: cytology every three years, high-risk HPV (hrHPV) testing alone every five years, or both together (cotesting) every five years [s1]. It concludes with high certainty that each of these strategies for the 30-to-65 group outweighs its harms [s1]. Screening is not recommended for women under 21, for women over 65 who have had adequate prior screening and are not otherwise at high risk, or for women who have had a hysterectomy with cervix removal for a benign condition [s1].

Where the American Cancer Society goes further

In 2020, the American Cancer Society moved ahead of that framework. Its guideline recommends starting screening at age 25 and undergoing primary HPV testing every five years through age 65 as the preferred strategy [s2]. Where FDA-approved primary HPV testing is not yet available, cotesting every five years or cytology every three years is offered as acceptable, but the guideline is explicitly transitional — those options are meant to be phased out as access to primary HPV testing improves [s2].

That marks two clear departures from the older model, which the ACS spells out. The recommended age to start screening rises from 21 to 25, and primary HPV testing is recommended from age 25 rather than from 30 [s2]. The reasoning is that HPV is the cause of nearly all cervical cancer, that HPV infections in the very young are common and usually clear on their own, and that a test for the virus is a more direct and durable marker of risk than a snapshot of cell appearance.

The visible disagreement — the Task Force screening from 21 with cytology, the ACS from 25 with HPV testing — is not a dispute about facts. It reflects different judgments about the youngest screening years and how quickly to retire cytology, made from the same underlying evidence that HPV testing is the more sensitive test. Both bodies are moving in the same direction.

The self-collection question

The other shift is who takes the sample. Because HPV testing looks for viral DNA rather than needing well-preserved cells read by a cytologist, it can in principle be run on a sample a woman collects herself. A large meta-analysis found that PCR-based hrHPV assays were about as sensitive on self-collected vaginal samples as on clinician-collected samples for detecting high-grade precancer (CIN2+ or worse), with a pooled sensitivity ratio of 0.99 (95% CI 0.97 to 1.02) [s3]. The same review found that assays based on an older signal-amplification method were less sensitive on self samples — so the test chemistry matters [s3]. Its other finding was arguably more important for public health: offering self-sampling raised participation among women who were irregularly or never screened [s3], the group that accounts for a large share of cervical cancers.

What this means for a reader

The practical picture is that HPV testing, on its own or with cytology, is now a mainstream cervical screening option for women aged 30 to 65, and one leading guideline would make it the primary test from 25 [s1][s2]. The recommended intervals — three years for cytology, five for HPV-based testing — are longer than the annual Pap many people remember, and that is by design, reflecting how slowly cervical cancer develops and how well the tests perform. Which strategy and interval apply to a particular person depends on age, history and what is available locally, and is a matter for a clinician. None of this replaces HPV vaccination, which addresses the cause upstream; screening and vaccination are complementary, not alternatives.

Sources

• [s1] Screening for Cervical Cancer: USPSTF Recommendation Statement, JAMA, 2018-08-21
• [s2] Cervical cancer screening for individuals at average risk: 2020 ACS guideline update, CA: A Cancer Journal for Clinicians, 2020-07-30
• [s3] Detecting cervical precancer and reaching underscreened women by using HPV testing on self samples, The BMJ, 2018-12-05