#76 About PAP Smears

In the 1920s a Greek physician, Georgios Papanikolaou, developed a screening test for cervical cancer. The test became known as the PAP test, named after him. The test procedure has undergone a number of improvements since Dr. Papanikolaou developed it, but the name has remained the same. This is what is known as a screening test and consists of taking a sample of cells from the cervix to check for cervical cancer. The early stages of cervical cancer have no symptoms, so the PAP test finds signs of cervical cancer in its early and treatable stages.

For years, women got a PAP test at their yearly physical exam. In the past couple of decades, screening tests of many different kinds have come under the scrutiny of researchers who often conclude that these tests needn’t be performed every year.

Over the last two decades, medical protocols in response to the research on screening tests have progressively increased the timing between Pap smears. The main advantage of having a PAP smear every year is that there is such a thing as a false negative (a smear that is labeled normal, but isn’t.) With traditional PAP smears, false negatives can occur 40 percent of the time. So, if you had a false negative smear in 2022 and you had another smear in 2023, the second smear can effectively check if the previous smear was accurate. In other words, it is extremely unlikely that you would have two false negative PAP smears in a row. With a PAP smear every year, with a false negative test result, you would go only one year with undiagnosed cervical cancer.

On the other hand, if you had a Pap smear every three years, the false negative would allow the cancer to grow for three years before a follow up PAP catches the previous false negative test result. The cervical cancer would have progressed much further in three than it would have in one year.

As noted previously, early cervical cancer is usually asymptomatic, so catching it in the early stages with a timely PAP smear can be very important in avoiding later state cervical cancers which are hard to treat successfully. However, there are five warning signs of cervical cancer:

  • Vaginal bleeding after sex
  • Vaginal bleeding after menopause
  • Vaginal bleeding between periods or periods that are heavier or longer than normal.
  • Vaginal discharge that is watery, has a strong odor, or that contains blood
  • Pelvic pain or pain during sex

In 2020, there were 604,000 new cases of cervical cancer reported worldwide, and 342,000 deaths from cervical cancer worldwide. Cervical cancer is the fourth most common cancer in women.

There is now a combination PAP smear and test for Human papillomavirus (HPV). This HPV test identifies the type of HPV virus. Some varieties are less aggressive than others. The combined PAP smear and HPV test decreases the false negative results of the PAP smear to 5 percent instead of 40 percent. The American College of Obstetricians and Gynecologists (ACOG) has an extensive explanation of PAP tests and the combination of the PAP test with the test for HPV and how often to have these tests.

What used to be a fairly simple decision to see your doctor and have a PAP test every year has gotten more complicated. Even with the combination PAP and HPV showing only a 5 percent false negative test result, ACOG suggests the combination test every five years and the PAP test by itself every 3 years. I still prefer to see the PAP test every year, so any false negative can be found quickly and treatment started while before symptoms of cervical cancer become obvious.