Originally published in The Ottawa Citizen November 26, 2002
Original Title: A Proven and Effective Means of Fighting Cervical Cancer
Medical research strives for the day when the diagnosis of cancer will no longer evoke fear. The goal to develop effective screening and treatment strategies to eradicate this disease continues to move forward. One of the ongoing success stories in this battle is the screening and early treatment of cervical cancer.
Cancer of the cervix is the third most common malignancy in the United States and the eleventh among Canadian women. Approximately 1300 Canadian women will develop cervical cancer and 400 will die this year. Worldwide, it is the second most common form of cancer in women and the leading cause of cancer death in developing countries. Why this discrepancy?
Cervical cancer is preventable through regular screening – simply put, having a pap smear. The data suggests that the Canadian primary health care system is better able to provide the screening resources to patients. Women who avoid screening or have no opportunity to do so are at increased risk.
Cervical cancer commonly peaks within two age groups; 35 to 39 years and 60 to 64 years. Since the introduction of Pap tests over 40 years ago, the incidence of cervical cancer decreased from 45 to eight per 100,000 women. Indeed, there has been an increase in detection and incidence of precancerous changes and invasive tumours over this same period.
Death from cervical cancer decreased from a rate of 11 per 100,000 in 1951 to 2.39 per 100,000 in 1995. The rate of decline in incidence and mortality was similar for all age groups. Women over 65 have the highest incidence and mortality rates.
Early detection improves survival; 92 percent of women survive cervical cancer that has not spread or metastasized while only 10 percent with metastatic disease live for five years.
Unlike other cancers, women have the means to minimize their risk of cervical cancer. Indeed other than low socioeconomic status and increasing age, most risk factors fall under individual lifestyle choices. These modifiable risk factors include early age at first intercourse, greater number of sexual partners, infection with human papilloma virus (HPV) and smoking.
The virus that causes genital warts, HPV, also infects the cervix. A majority of women with cervical cancer and precancerous changes have HPV infection. In the United States, 20 percent of teenagers and 40 percent of women 20 to 29 years of age harbour HPV. Canadian rates are similar.
It can take years for the infection to cause cancer. HPV represents a class of about 50 to 60 viruses (subtypes). Only some of these subtypes cause cancer. Many women with HPV infection do not develop malignancies. Some precancerous changes spontaneously improve. Careful monitoring of these changes is mandatory.
HPV infection alone is not enough to cause cancer in some situations. One U.S. study of 296 women compared nonsmoking women without HPV (the control group) to three other groups: smokers, HPV infection alone and both smoking and HPV infection. The relative risk of pre-invasive cancer was two, 15 and 66 times more than the control group respectively.
This significant relationship persisted after adjusting for age and number of sexual partners. The longer someone smokes the greater the risk. Breakdown products of cigarette smoke have been found to concentrate in cervical mucous. The evidence implicates cigarette smoking as a co-conspirator with HPV with direct cancer-causing (carcinogenic) effects on the cervix.
Condoms are not foolproof protection from HPV because genital warts are not restricted to the genitalia. They can spread to the scrotum, anus and pubic areas. Skin to skin contact will pass the virus from one person to another. Treatment for HPV exists but early detection and treatment can reduce the duration, cost and complexity of therapy.
Treatment of cervical cancer depends on the patient’s age, their overall health, the desire to have children, the stage of the disease and size of the tumour. Treatment of advanced disease usually requires invasive surgery and radiation therapy.
Primary prevention is the best means of controlling this disease. This includes the sexual history of a new partner, screening of sexually transmitted infections (STIs) prior to any sexual activity, smoking cessation, being vigilant and delaying the onset of sexual intercourse.
The Pap test is the best means to date to screen for cervical cancer. Many women come into the office resigning themselves to this examination often with gender specific comments about their boyfriends and husbands best left to one’s imagination. Men, you don’t have a clue! Despite the compromising yet painless examination, it saves lives.
The Canadian Task Force on the Periodic Health Examination recommends annual screening with the Pap smear after initiation of sexual activity. A Pap test should be done after intercourse with a new partner. Women in long-term monogamous relationships having had two previous normal annual Pap smears can be screened every three years until age 69. Although the bane of many women, the cost of avoidance is too high.
© Dr. Barry Dworkin 2002