A lot has changed since George Papanicolaou first discovered abnormal cells under a microscope while looking at a vaginal smear. In the 1920s, he wasn’t looking for a screening test for cervical cancer. His research was geared toward understanding the cellular changes that occur in response to hormones during the menstrual cycle. It turned out that one of the women that were sampled had uterine cancer and he noticed abnormal cancer cells on the slide he had prepared. This led him to consider the possibility of looking for abnormal cells as a way to detect cervical and uterine cancers. His idea was not taken seriously for several years but as we now know, the “Pap” smear gradually became widely used and has helped save millions of lives and made cervical cancer much less common in countries where screening is widely practiced. Unfortunately, even in the United States, cervical cancer kills 4000 women per year and many more in less developed countries.
For decades no one had any idea that most cervical abnormalities were caused by a virus. Over the past 30 years, the Human Papilloma Virus (HPV) has been proven to be the primary trigger for cellular abnormalities that can lead to cervical cancer. Technology has improved allowing microbiologists to identify more than 100 different strains of HPV. Many strains seem to do little damage, causing minor and transient changes on the cervix and resolve spontaneously. Other types are more likely to cause genital warts. “High Risk” types of HPV are most often associated with precancerous changes known as “high-grade cervical dysplasia”. These types of changes in the cervix can potentially become cancerous and therefore merit closer observation and treatment.
The ability to test for specific types of HPV allows screening and treatment of cervical abnormalities to be more precise and tailored to the findings in each individual. As many women remember, Pap smears used to be recommended every year. With a better understanding of the virus that triggers abnormalities and the progression of the diseases it may cause, several new changes have been made to the recommended schedule for Pap smears and the evaluation of abnormalities.
The current recommendation for screening intervals is in part age-dependent. Pap smears are no longer recommended for women under age 21. This is because most of the infections detected in younger women resolve spontaneously and do not need treatment. Pap smears are recommended starting at age 21. Overtreatment at a young age can lead to problems with fertility and pregnancy in the future.
Women between the ages of 21 and 30 should have Pap smears every three years if normal. If an abnormality is detected then either closer surveillance with additional Pap smears or treatment may be recommended. After age 30 a Pap smear will often be combined with testing for the high-risk types of Human Papilloma Virus (Co-testing ). If the Pap is normal and no HPV is detected, surveillance may be continued every three years. Some gynecologists even suggested as long as five years before co-testing again, although my personal opinion is that this is too long between screenings. A woman over 65 with no history of recent abnormal Pap screening may choose to discontinue them. There are plenty of other things that may be discussed and checked at the time of a gynecology visit so I still recommend regular visits even if a Pap smear is omitted.
Until recently, preventing cervical cancer has relied on early detection and treatment of the cancer precursor known as dysplasia. One of the most important new tools now available is a vaccine against the HPV virus that causes the disease. Although it doesn’t protect against all strains, it does cover the most virulent strains that cause 70% of cervical cancers and 90% of genital warts. The HPV vaccine (Gardasil) is now recommended for adolescents at around age 12. Since HPV is transmitted through sexual intercourse it is ideal to have the vaccine series prior to the onset of sexual activity. Because HPV may be contracted and passed on by either males or females it is recommended for boys and girls.
This is the only vaccine that can prevent cervical cancer and yet it is still underutilized because of the cultural/religious expectations regarding teen sexuality and parental hope that their children will practice abstinence. Although I fully support the notion of abstinence, I have been a parent and gynecologist long enough to understand that the reality is a large percentage of teens have sex before they’re even out of high school. And, even if one individual does abstain until marriage, there is no guarantee that the person they fall in love with has done the same.
Cervical cancer is almost entirely preventable. Every woman I have diagnosed with cervical cancer has gone years without screening. Although no one particularly enjoys a visit for this testing, it may be life-saving. As time goes on and HPV vaccination becomes mainstream and accepted, I hope that the need for me to treat cervical abnormalities will disappear.
