Just to make sure we all start at the same baseline: a cervical Pap smear is done when a physician or other medical professional uses a small, soft plastic brush to collect cells from the surface of the cervix. The cervix is the lowest part of the uterus (womb.) The cervix can only be seen after a speculum, which is a plastic or metal tool shaped like two serving-size spoons, is placed in the vagina. The speculum exam is also called a “pelvic exam.” Many women assume that every pelvic exam includes a Pap smear, but that is not the case. If the examiner does not mention whether or not a Pap was done, the patient should ask.
The Pap test was invented in 1929 by Dr. Georgios Papanicolau. It came into widespread use as a screening test for cervical cancer in the 1950s. At that time, cervical cancer killed more women than any other type of cancer. Pap screening is so effective that today, cervical cancer is not even one of the top ten most frequent cancers in women. By the 1980s, the rate of cervical cancer had decreased by 70% – to less than a third of the rate before Pap smears. At that time, the general recommendation was that women should have a Pap smear every year starting at age 18 or at the start of sexual activity, with no recommendation about at what age Paps could be stopped. Many authorities also recommended that Pap smears should continue even after a hysterectomy, even though the cervix has been surgically removed.
There have been important advances in the understanding of cervical cancer since then.
First, it was shown that cervical cancer is a slow growing cancer, so it can be identified in the early stages even if testing is done less often than once a year. Guidelines changed to recommend that if a woman has had three normal Pap tests in a row and has never had had any form of cervical cancer, she can decrease Pap frequency to every three years. This rule applies only if she is not pregnant, has had no new sexual partners since her last screening, and is not having any abnormal discharge, bleeding or pain. The recommendation for when to start Paps changed to begin three years after the start of sexual activity, regardless of age. And women over 65 could stop getting Paps at age 65 if their last three Paps showed no signs of cancer.
An even more significant change occurred when it was proved that cervical cancer is a sexually-transmitted infectious disease. It is caused by a few particular strains of HPV, the human papilloma virus. This discovery opened up new ways of thinking. A new vaccine was released in 2006 to prevent HPV and therefore prevent cervical cancer as well as several other types of cancer caused by HPV. This vaccine, called Gardasil, is recommended for all boys and girls in the pre-teen years. Tests have been developed to look for the HPV virus itself in the cervical cells rather than looking for the pre-cancerous or cancerous cells that develop several years after the start of infection. The test is so accurate at detecting the earliest signs of HPV infection that if a woman is over 30 and her test for HPV is negative, she can decrease her Pap smear frequency to every five years. HPV testing is not recommended for women younger than 30, because in younger women most HPV infections clear up on their own and do not require treatment.
It is now generally accepted that Pap smears are not necessary for women over 65 if they are not having new sexual partners. Paps are also unnecessary for women who have had hysterectomies as long as the hysterectomy was not done because of cancer. The cervical Pap smear is still the most effective test ever developed for early detection and treatment of cancer. It is also the most cost-effective cancer screening test.
These guidelines apply only to women who aren’t pregnant, are healthy, have never had any type of cervical or uterine cancer, have no problems with their immune system (such as HIV), who have not had a new sexual partner since their last Pap smear, and are not having any problems with vaginal bleeding, discharge, itching, or pelvic pain. If any of those things are happening, a pelvic exam and possibly a Pap smear may need to be done earlier than usual.
Eva Hersh, MD, is a family physician. Please send questions and comments to her by email at email@example.com