Dr Haynes van der Merwe,
Specialist Gynaecologist and Subspecialty Gynaeoncology
Cervical cancer is one of the most preventable forms of cancer, yet it remains a significant health concern worldwide and even more so in South Africa where the incidence rate is almost three times higher than the global average. In South Africa, cervical cancer is the second most common cancer among women with more than 10 000 new cases diagnosed each year and it is the leading cause of female cancer deaths each year. It can be prevented and lives saved through effective primary prevention early detection (prophylactic HPV vaccine) and secondary prevention (regular screening).
What is Cervical Cancer?
Cervical cancer occurs in the cells of the cervix—the lower part of the uterus that connects to the vagina. Most cases are caused by persistent infection with high-risk types of the human papillomavirus (HPV). Most HPV infections resolve on their own, but some can lead to abnormal cell changes and eventually cancer if not detected and treated early.
Why is Screening Important?
Screening helps detect abnormal changes in cervical cells before they turn into cancer. Thereby it allows for timely treatment of precancerous lesions and significantly reduces the chances of these lesions to develop into cancer. Regular screening is especially important because cervical cancer often develops slowly and may not show symptoms until it is advanced.
Screening Methods
There are two main types of cervical cancer screening tests. Both tests are performed on a specimen collected form the cervix by a healthcare worker:
1. Pap Smear (Pap Test): This test involves the evaluation of cells that exfoliate from the cervix to check for abnormalities. It has been the standard screening method for many years and used to be the preferred option.
2. HPV Test: This test detects the presence of high-risk HPV types that can cause cervical cancer. Because it is more sensitive than the Pap smear and can be done less frequently, HPV testing has been phased in to replace the Pap-test as the preferred primary screening test.
Initiation of screening
Because of the high background risk of HIV in South Africa the recommended age to start screening is 25 years. In low-risk subpopulations the age of first screening may be delayed to the age of 30 years. It is not recommended to screen asymptomatic women under the age of 25. Women under the age of 25 who are concerned about their risk of cervical disease because they are HIV positive or present with genital symptoms (bleeding, pain or discharge) should rather have a Pap-test.
Screening interval
The recommended interval between HPV screening tests, provided the previous test was negative, is five years. In a resource-limited setting the screening interval can be extended to ten years. In women living with HIV or those who had a previous positive HPV test the screening interval should be shorter than the recommended five years.
Self-Sampling for HPV Testing
Self-sampling is a newer, more convenient method that allows women to collect their own sample for HPV testing using a swab and has been widely accepted. This method is especially useful in communities with limited access to healthcare facilities and can increase participation in screening programs. Studies have shown that self-sampling is as effective as clinician-collected samples for detecting high-risk HPV. Self-sampling test kits are available from most big pharmacies and pathology laboratories. The disadvantage of self-sampling is that cervical cells are usually not represented in the sample. Women who have a positive HPV test will then require a second healthcare worker collected sample to ensure the collection of cervical cells for evaluation.
Guidelines for management of abnormal tests
Women who test negative for all the high-risk HPV types (14 types in total) have a very low risk to develop cervical cancer and should have a repeat HPV test three (HIV positive women) or five (HIV negative women) years later. Those with a positive HPV test are divided into an intermediate-risk group or high-risk group. Further management of these two risk groups are different and women with a positive HPV test should be referred to a gynaecologist or healthcare worker trained in the management of patients with positive HPV tests.
Barriers to Screening
Despite the availability of screening, many women unfortunately do not get tested due to lack of awareness, fear, stigma, and limited access to healthcare services. Education and outreach are essential to overcome these barriers and ensure that all women have the opportunity to protect their health.
Conclusion
Cervical cancer screening is a powerful tool in the fight against cancer. With regular testing, early detection and timely treatment of precancerous lesions, cervical cancer can be prevented. Whether through HPV testing or Pap smears of healthcare worker collected specimens, or self-sampling, it is important for women to understand their options and take proactive steps toward their health.
