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CERVICAL CANCER PREVENTION The prevention of cancer is one of the biggest challenges in American medicine. A tremendous amount of manpower, brainpower and financial resources are consumed in this mightily important endeavor. After all, the best cure for cancer is to prevent it. In all its forms, cancer is the second leading cause of death in the United States. Approximately half of all men and one third of all women will develop cancer during their lifetimes. Efforts at prevention have met with varying degrees of success, depending on the type of cancer. The prevention of cervical cancer may well be the crown jewel in this effort.
Death due to cervical cancer, once the leading cause of cancer-related death in American women, now ranks thirteenth. Between 1955 and 1992, the cervical cancer death rate dropped by 74% and continues to decline by 2% per year. The reason for this dramatic improvement is due largely to the introduction of the cervical Pap smear approximately 50 years ago. Microscopic examination of the Pap smear can detect changes in the cells of the cervix before cancer develops, allowing your physician the opportunity to initiate appropriate therapy early in the course of the disease; ultimately preventing the development of cancer. To illustrate the importance of the Pap smear, cervical cancer is still the number one cause of cancer-related death among women in many countries where the Pap smear is not widely available.
What is the Pap smear and how is it done?
Because the cervix is easily accessible, it lends itself to sampling of the cells on its surface. It is these surface cells that develop the precancerous changes, also referred to as “dysplasia”, which when left untreated can potentially become cervical cancer. The Pap smear is simply a method of obtaining cells from the surface of the cervix so that they can be examined under a microscope. This process is initiated by scraping and/or brushing the surface of the cervix with special instruments. The sample then needs to be transferred to a glass slide for microscopic examination. There are two methods for preparing the slides for microscopic evaluation. The cells that were scraped from the cervix can be directly smeared on a glass slide and preserved by spraying with an alcohol preservative. The slides are then sent to a pathology laboratory for examination. Although this is a perfectly adequate method, and was the only method for about 50 years, it does have limitations. Some of these limitations can result in an indeterminate diagnosis, necessitating a repeat Pap smear. This, of course, means another visit to your doctor. A newer method, which has been developed over the past few years, is the “liquid-based cytology” method, most commonly marketed as the ThinPrep® Pap smear. This method requires your physician to directly place the cells he/she scraped from the cervix into a liquid preservative. The entire specimen is sent to a pathology laboratory where specialized technology is utilized to prepare slides in a very precise, reproducible manner. Slides prepared in this manner can be interpreted with greater accuracy as compared to the older method. With this new method, you can feel confident that you are getting the best possible care with fewer indeterminate diagnoses and fewer repeat Pap smears. At Pee Dee Pathology Associates, we have been utilizing this technology for more than five years and 99% of the physicians who send us Pap smears now use this method. This represents a commitment, by everyone involved, to provide the women of the Pee Dee the highest quality Pap smear service available.
What are the risk factors for cervical cancer?
Having a risk factor does not mean that you will get a disease, only that you have increased the odds of getting a disease compared to someone who does not have the risk factor. The risk factors for precancerous changes (dysplasia) and cancer of the cervix include: - Human papilloma virus (HPV) infection: this is the most important risk factor (discussed in detail below) - Smoking: women who smoke are about twice as likely to develop precancerous changes and cervical cancer as nonsmokers - Diet: women with a diet low in fruits and vegetables may be at higher risk - Chlamydia infection: this is a relatively common infection of the cervix that is transmitted sexually. It appears to be associated with a higher risk of precancerous changes in the cervix; however, further studies are needed - Family history: studies suggest that women whose mothers or sisters have had cervical cancer are at higher risk - HIV: this virus damages the immune system which makes a women more susceptible to HPV infection, thus, at higher risk for precancerous changes and cervical cancer
What is HPV?
Human papilloma virus (HPV) is the most important risk factor for the development of precancerous changes and cancer of the cervix. In fact, HPV is considered necessary for the development of these changes. Understanding the role of this virus in cervical cancer development has been a major breakthrough in women’s health. HPV is actually not just one virus but a family of about 100 viruses. Some types of HPV cause the typical warts that one may get on the skin. However, certain types of HPV infect the cervix. These types of HPV are transmitted by sexual contact. When HPV infects the cells on the surface of the cervix, it can cause an abnormal change in these cells (dysplasia). It is in this background of abnormal cells that cervical cancer can develop. Therefore, as amazing as it seems, cervical cancer is actually the result of a virus infection gone awry. Risk factors for exposure to HPV include: - intercourse at an early age - multiple sexual partners - intercourse with individuals who have had multiple sexual partners A significant percentage of women under the age of 30 will have HPV infection of the cervix at some point. The good news is that the vast majority of these women will either clear the virus without any problems (develop immunity) or develop only mild precancerous changes of the cervix that can be managed conservatively. However, some women will develop more worrisome precancerous changes that will require more aggressive therapy. These women, if left untreated, have a significant risk of developing cervical cancer.
How does the Pap smear help us detect HPV infection and precancerous changes? When HPV infects the cells of the cervix, it causes changes in the cells that can be seen under the microscope. These changes are effectively the virus’ calling card. The virus itself is not actually seen. Remember that a Pap smear is just a snapshot of a dynamic process. One can draw an analogy to a crime scene photograph in which you are trying to look for clues about what happened based on a still photo. The clues for an HPV infection and precancerous changes are usually obvious when examining the Pap smear. Occasionally, however, these changes can be quite subtle. In these situations we may need to resort to new DNA-based technology to directly detect the virus. DNA is the genetic material that identifies the virus. This HPV DNA test represents cutting edge technology that not only allows us to detect the DNA of the virus, thus identifying its presence, but also determines if it is high-risk or low-risk HPV. This provides your physician with very important information with which he/she can plan your treatment effectively. This is another situation where the liquid-based cytology (ThinPrep®) method is most beneficial. With liquid-based cytology, we can test for HPV DNA in the same sample your physician initially sent for the Pap smear evaluation, eliminating the need for the patient to come in for a repeat visit to provide another sample for HPV DNA testing. Again, this is all about providing the highest level of care with the least amount of inconvenience to the patient.
Although the Pap smear is a powerful screening tool for the prevention of cervical cancer, it is not perfect. The real power of Pap smear screening depends largely on having regularly scheduled tests so as to increase the likelihood of detecting an abnormality. It must be remembered that any single Pap smear is nothing more than a snapshot of what is going on at that point in time. The situation may change; therefore, regular examinations are necessary. The American Cancer Society provides recommended guidelines for Pap smear screening on their website www.cancer.org. These guidelines should be discussed with your physician to determine what is best for you.
The Pap smear has served as the cornerstone of cervical cancer screening for the past 50 years. It is the widespread availability of this test that has had such a tremendous positive impact on women’s health in this country. With the recent advances in technology, including liquid-based cytology and HPV DNA testing, accuracy of diagnosis has never been better. By offering these state of the art testing methods locally, Pee Dee Pathology Associates is committed to providing the highest level of service to the women of the Pee Dee.
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