UNIVERSITY PARK – Although cervical cancer is the leading cause of cancer deaths among women worldwide, in the United States, regular Pap testing has made cervical cancer less formidable. Early detection has reduced the rate of invasive cervical cancer. Nonetheless, about 11,000 women will be diagnosed with cervical cancer in the United States this year and about 4,000 will die from it. Most of these deaths will be in those women who have not been screened either through lack of access or avoidance of testing.
Research has discovered that cervical cancer is caused by a virus called the human papilloma virus (HPV) which is sexually transmitted. There are many strains of HPV — some cause common warts, but four are responsible for most of the cervical cancer and some others cause genital warts. Strains that infect the hands and feet do not infect the vagina or cervix and vice versa.
The cervix is the opening to the uterus or womb and is situated at the upper end of the vagina. HPV is introduced into the cervix during intercourse. The more sexual partners a woman has, the more likely she is to be infected. At least half of all sexually active people become infected with at least one strain of HPV. Fortunately, most of these are cured by a healthy immune system and never cause a problem. Some, however, go on to cause changes that lead to cervical cancer.
The only way to tell if cancer is developing is to do an examination of the cervix and to take a sample for microscopic analysis — the Pap smear. While the laboratory analysis of Pap specimens has improved over the years, the only way to obtain the sample remains the same — by a pelvic exam.
Sexually active women should have annual Pap exams beginning in the third year after starting sexual activity or age 21, whichever is first. Women who are either not sexually active or who are in a stable sexual relationship with one person could possibly change to an every third year Pap, but many physicians disagree. One concern is that remembering to have an exam annually is easier than remembering it every three years. Without an effective reminder system, a woman could find it has been a much longer time since her last Pap. Also, it can be difficult to be certain that both partners in a relationship have not had other sexual contacts. After age 65, cervical cancer is much less likely, so for nonsmoking women with no other risks, Pap exams can be stopped.
Since cervical cancer is sexually transmitted, the earlier sexual activity begins and the more sex partners a woman has, the greater her risk. Condoms do not reduce risk as in other sexually transmitted diseases. Lesbian women do not have a lower risk of cervical cancer than heterosexual women and also should be examined annually. Smoking and second- hand exposure increase the risk of cervical cancer probably by tobacco’s deleterious effects on the immune system.
Sometimes a Pap is mildly abnormal. Some terms that might be used in the report include atypical squamous cell of undetermined significance (ASCUS) or low grade intra-epithelial lesion (LSIL). These do not indicate cancer and most of the time these conditions resolve without treatment. When the Pap shows a mild abnormality, typically the sample is tested for the presence of a cancer associated strain of HPV and treatment is directed to this result. Sometimes, no treatment is needed, just a repeat Pap to confirm the infection has resolved.
Until recently, Pap smears and HPV testing were the state of the art in cervical cancer prevention. Now there is a vaccine for the HPV virus which causes cervical cancer — the first-ever cancer vaccine. This vaccine was developed thanks to work done at Penn State College of Medicine in the 1980s and ’90s, when researchers created the first animal model for human HPV. This model allowed researchers nationwide to test various HPV treatments and vaccines. The currently available vaccine induces immunity to the two most common HPV strains causing cervical cancer plus two common strains of genital wart HPV. The three dose series reduces the risk of cervical cancer by 70 percent and genital warts by 90 percent. Although women will still require Pap exams annually since it is not a total preventive vaccine, the likelihood of abnormal Paps and deaths from cervical cancer is greatly reduced.
The ideal time for receiving the vaccine is before sexual activity begins, but it is reasonable to administer to any female during the currently approved ages of 9 through 26 even if she is sexually active since she might not have contracted the strains covered in the vaccine. Vaccines are like seatbelts — you might not need them, but if you do, it’s best to have it ahead of time.
One day, cervical cancer might be totally preventable. Until then, the risk of invasive cancer of the cervix can be reduced by vaccination of appropriate women, delay in onset of sexual activity and limiting partners for both heterosexual and lesbian women, avoidance of tobacco and annual Pap exams.
More information on cervical cancer can be found on the Web.