Some experts question the usefulness of Pap testing going forward. But how would cutting back on Pap testing affect clinical laboratory revenue and is it safe for cancer patients?
Recently, a major medical society issued its findings that cervical cancer in the United States has been on a sustained decline for more than a decade and a half. This confirms what cytopathologists and cytotechnologists have watched as the development of new clinical laboratory tests, and the introduction of a vaccine for HPV (human papillomavirus) about 15 years ago, contributed to a reduction in the number of cervical cancer deaths annually here in the United States and in several other nations.
Pap tests have been a primary screening test for cervical cancer since the 1990s. As such, they also have been a major source of revenue for clinical laboratories that performed the tests. Now, the American Society of Clinical Oncology (ASCO) has published a study, titled, “HPV-Associated Cancers in the United States Over the Last 15 Years: Has Screening or Vaccination Made Any Difference?” The study authors wrote that “Over the last 16 years, the incidence of cervical cancer has decreased at an annual percent change (APC) of 1.03% (p<0.001).”
As incidences of cervical cancer declined, so have orders for Pap tests. Thus, clinical laboratory revenues in this area also have declined. This is a change from the 1990s and early 2000s, when Pap tests were the primary screening tool for cervical cancer. About 55 million Pap tests were performed annually during those years and many labs maintained sizeable numbers of cytotechs to perform these tests.
HPV Testing Drove Decreases in Cervical Cancer, Decline in Pap Testing
For at least the past decade, there are pathologists, cytotechnologists, and medical laboratory scientists who graduated from their training programs and began working in labs unaware that, since the 1990s, conventional Pap testing as a major source of test referrals and revenue for clinical laboratories and pathology groups has been on the decline.
What is the reason for the decline? Advances in several areas of medicine, implemented over the past 25 years, have greatly altered how we screen for cervical cancer today. And, in a stepwise fashion, the HPV test and HPV vaccine steadily reduced the role of Pap tests as a primary screening tool.
The ASCO study showed incidence of cervical cancer in the US has decreased more than 1% each year for 16 years amid HPV screening and vaccination guidelines. Thus, the US may be on the same path as Australia, which—according to research Dark Daily cited in “Australia’s HPV Vaccination Program Could Eliminate Cervical Cancer If Its National HPV Vaccination and Screening Programs Remain on Current Pace,” has nearly eliminated cervical cancer rates due to HPV screenings and vaccinations.
HPV, a common sexually-transmitted virus, is linked to not only cervical cancer, but also cancers of the vulva, vagina, penis, and anus, according to the Centers for Disease Control and Prevention (CDC) data, which recorded 43 million HPV infections in the US in 2018.
Cervical Cancer Down, But Other HPV Cancers Up
Though cervical cancer incidence is down, other HPV-related cancers may need additional screening standards to head off rising cancer cases, the ASCO study suggests.
To conduct their study, the ASCO researchers analyzed data for 657,317 people in the US Cancer Statistics (USCS) program from 2001 to 2017. The researchers reported their findings at the 2021 ASCO Annual Meeting held online in June. They include:
- Cervical cancer incidence rate decreased each year by 1.03% annually over 16 years.
- In the 20 to 24 age group, a “disproportionately higher decrease” of 4.6% per year in cervical cancer incidence rate suggested “potential effect of vaccinations.”
- Without screenings, HPV-related cancers incidence increased in women over 16 years.
- Oropharyngeal, anal, rectal, and vulvar cancer increased 1.3% in women per year.
- In men, oropharyngeal cancer incidence represented 81% of all HPV-related cancers—five times more than cases for women over 16 years.
- HPV-related cancers in men increased 2.36% per year over 16 years, and oropharyngeal cancer had the biggest increase.
“Without standardized screening, HPV-related cancers—such as oropharyngeal cancers and anal rectal cancers—are increasing. To reduce these trends and achieve success comparable to what we’re seeing with cervical cancer we must develop effective screening strategies and determine vaccine efficacy in these patient populations,” Liao said in the news release.
Should PAP Tests Be Dropped as a Primary Screen for Cervical Cancer?
Today’s American Cancer Society (ACS) guidelines for cervical cancer screening denote the primary (FDA-designated) HPV test as the “preferred test” for people 25 to 65 years of age. A Pap test (or Pap smear) can be done at the same time, or in instances when a primary HPV test is not available, the ACS said.
HPV screening aims to detect high risk strains of HPV by looking for DNA in cervical cells and the Pap test involves collecting cells from the cervix for review in the medical laboratory for cancer and pre-cancer, the ACS added.
However, pathologists and cytotechnologists who have examined Pap smear slides for many years know that indications of cervical cancer are not always detected by HPV screening. A Pap test often picks up indications of cervical cancer that might not have been detected by the HPV test.
One reason is HPV tests only monitor about 20 of the genetic mutations known to cause cervical cancer. There are about 80 mutations that can cause cervical cancer, but most are so rare, it does not pay to include them in the HPV test panel.
“The Pap is not something that we should look at as replaceable. In some circumstances, we can get a Pap smear that has some significant cellular changes on it,” Jessica Shepherd, MD, an obstetrician and gynecologist at Baylor University Medical Center in Dallas, told USA Today.
Medicine Advancing, Pap Referrals Not So Much
In the 1990s, Pap tests were the front line for cervical cancer screening and a source of about 55 million referrals to clinical laboratories each year, recalls Robert Michel, Editor-in-Chief of Dark Daily and its sister publication The Dark Report.
“Interestingly, in the past decade, many cytotechnologists and laboratory scientists who started work in labs at the time of the new HPV screening guidelines and vaccination were unaware of the Pap test’s impact on revenue for clinical labs and pathology groups,” he said.
Medical advancements over the past 25 years have altered how providers screen women for cervical cancer and help them prevent it. And as HPV screening and HPV vaccination gained prominence, the standard Pap test became a kind of “co-pilot” to HPV testing. Unfortunately, this meant less oncology referrals to medical labs.
—Donna Marie Pocius