Cervical Cancer… Making It Obsolete

Proof of how far medical science has come:  Fewer and fewer American women are diagnosed with cervical cancer every year (although the disease continues to be the number one killer of women in many developing countries.).  Credit goes to widespread use of the Pap test and newer screening tools and treatments that are reducing incidence in the United States even further.  There is also the new human papillomavirus (HPV) vaccine, which is recommended for girls 11 to 12 and is approved for ages 9 to 26.  If it works out as well as doctors hope, cervical cancer may one day be as rare as measles.

But not yet, as Washington, D.C. Legislative Director Paige Anderson found to her surprise.  In 2004, when she was 36, her periods lengthened and became more frequent, and sex was painful.  When the gynecologist she consulted began to insert a speculum, it hurt so much he had to stop.  In a follow-up visit using anesthetic, he found a tumor so large it was visible when he did the exam.  When a biopsy came back positive for late-stage 1 cervical cancer, Anderson was stunned.  “I have never had an abnormal Pap in my life,” she says.  She underwent a hysterectomy.

Looking back, Anderson is amazed by her own naiveté.  “I knew I was supposed to see my gynecologist every year for a pelvic exam, but I hadn’t gone in three years,” she says.  “I knew I was supposed to have a Pap smear, but I didn’t know it detected cervical cancer.”

For more than 50 years, the Pap has been the gold standard in cervical cancer screening.  But any test is only good if it is used, and most women who get the disease have either never had a Pap or haven’t been screened in five years.  That having been said, doctors and labs can also miss cancer — or the specimen may be sub-par (a problem largely fixed by newer liquid-based Paps, including the latest, even-more-accurate type called MonoPrep, which became available in 2006).

The Pap looks for abnormal cervical-cell changes, which are usually caused by certain strains of HPV, one of the nation’s most common sexually-transmitted diseases.  Now there is also an HPV DNA test that can detect the virus long before it causes malignancy, using the same sample that the doctor takes for a Pap.  First approved by the FDA in 2000 for use in women with abnormal Pap results, it is now also approved for use with the Pap to screen women over age 30 for cervical cancer.

So-called dual screening is far more accurate than doing the Pap alone.  A Canadian study published in the New England Journal of Medicine in October 2007 found that the Pap identified only 55% of high-grade cervical lesions, compared with 95% for the HPV DNA test, which screens for 13 potential cancer-causing strains.  “These are the more worrisome pre-cancers that we know, without treatment, could progress and possibly lead to cancer,” says Debbie Saslow, Ph.D., Director of Breast and Gynecologic Cancer at the ACS.  “When the tests are used together and come back normal, they are spot-on close to 100% of the time.”

If HPV testing is so accurate, why not scrap the Pap?  The Pap test finds pre-cancer and cancer, but the HPV test also picks up many strains that may never become cancerous.  Indeed, “Most new HPV infections go away on their own in six to 18 months,” says Diane Solomon, M.D., Senior Investigator in Cancer Prevention at the NCI.  If the HPV test is positive but the Pap is negative, there is a low risk for cancer.  All that is needed is to repeat both tests 12 months later.  If the doctor only had the HPV results, prudence would require prompt follow-up by a biopsy.  This would result in “doing colposcopy on tens of thousands of women who don’t need it,” says Dr. Solomon.  The Pap is also the screening test of choice for adolescents and young women because they have high rates of HPV “but a very low risk of cervical cancer,” says Dr. Solomon.