This month’s Science of Sex was inspired by research I was doing myself based on my own health, so this post will be a bit more anecdotal/personal than usual.
I’ve been getting Pap smears since I was 18. If I had to get, I’ve had about a dozen or so — one every year until a positive HPV result when the exams became twice yearly. After things returned to normal, I went back to annual paps. Seven years ago, the American Cancer Society changed recommendations official to three years, so my visits became less frequent. As an American, I went according to the suggested schedule because I thought it was helpful; although, I realize other countries have different recommendations. I imagine that many women, trans men, and nonbinary folks have followed a similar schedule.
I don’t know if the HPV test has always accompanied my paps, but it has a good portion of them. Combination testing is recommended for anyone over 30 as it’s believed that people in their 20s may have transitory strains of HPV that will be suppressed by the younger person’s immune system. The HPV test can now detect the very strain of HPV (13 of the highest-risk strains), which is helpful to prevent cervical cancer and benefits treating HPV itself.
Read more about HPV and the vaccine.
Imagine my surprise several months ago when my pap came back clear, but I was positive for HPV 16. For those who may not be familiar, the pap smear is a collection of cells using a swab. The swab can miss areas of the cervix where cells may be abnormal, so false negatives are possible. On top of that, false positives are also possible. Because samples are sent away to a lab where a person must identify if cells are abnormal are not, there’s a pretty high margin of error.
According to one 1996 article,
Pap smears, which can detect cancer of the cervix, are now said to have a false negative rate of 20 to 40 percent.
Things may be looking up; however. Modern paps experience false negatives been 10% and 20% of the time.
A false negative could allow abnormal cells to spread and potentially turn pre-cancerous or cancerous. However, a false positive can result in unnecessary, invasive procedures. My HPV results have led to biopsies colposcopies, which enabled doctors to examins the cells of my cervix to locate and sample abnormal cells. After finding moderately abnormal cells this time around, I was referred for a procedure known as a LEEP that involves cauterization of the cervix.
Considering that abnormal cervical cells are not uncommon and not always caused by HPV and can clear up by themselves, which could make any followup procedure unnecessary.
This leads me to the crux of this post: HPV tests alone are more accurate and better predictors of cervical cancer than paps. In fact, people have questioned how useful paps are as a tool for over two decades. Clearly, co-testing (combining both HPV testing and pap smears) is effective, but it may be effective enough to simply perform HPV testing.
However, for those people who may not routinely undergo STI screenings, the recommendation that paps should be performed less frequently may mean less frequent HPV testing as well. Because HPV testing can indicate when a person’s immune system is no longer suppressing the virus in addition to new viruses, it might be helpful to increase the recommendation for HPV testing even as paps become less frequent especially considering that the CDC now states virtually everyone who is sexually active will have HPV, and it may have gone unnoticed because of a faulty pap, or may reappear during times of a weakened immune system.
Further Reading
- Screening for Cervical Cancer: U.S. Preventive Services Task Force Recommendation Statement
- HPV Testing in the Evaluation of the Minimally Abnormal Papanicolaou Smear
- Study Suggests HPV Test More Accurate Than Pap Smear for Cervical Cancer Screening
- Accuracy of cervical cytology: comparison of diagnoses of 100 Pap smears read by four pathologists at three hospitals in Norway
- Detecting High-Risk HPV in Older Women
- Human Papillomavirus and Cervical Cancer
- Cervical Cancer
- HOW ACCURATE IS THE PAP TEST?
- Pap smear
- The HPV DNA Test
- Screening for Cervical Cancer: US Preventive Services Task Force Recommendation Statement.
- HPV-DNA testing for cervical cancer precursors: from evidence to clinical practice
- Why I’ll never have another smear test
- Cervical screening
- BODY AND MIND; Is the Pap Test Valid?
