Cancer is a word that fills most people with dread. But, with regular testing, it can be detected and treated…
Few diseases give us an opportunity to perform tests to predict its development. Some cancers are among those and the test is called screening. It can predict the development of disease before it is obvious or while it is still in the early stages. Effective screening tests are usually cheap, minimally invasive and sensitive to pick up disease; and the disease must have a cure that is acceptable to users.
In gynaecology, the screening of certain specific cancers can prevent significant morbidity and mortality. These include ovarian, uterine, cervical, vaginal and vulval cancers. In South Africa, the following four are noteworthy in terms of prevalence, prognosis and survival.
Cancer of the ovary has two age peaks, early in life (teenage and early adulthood) and later, during the postmenopausal period. The cancers associated with these peaks are different, and have slightly different progression and management implications.
Screening has low sensitivity and specificity, meaning it can miss many cancers and may be unable to differentiate in the general population. Women with a strong family history of cancer may benefit from genetic screening. There are familial genes that put some families at higher risk than the rest of the population. If a woman has close relatives with breast, ovarian, stomach, bowel or pancreatic cancer, it may be worthwhile testing her.
Routine screening is not useful and becomes extremely costly. It is important to know that ovarian cancer may be subtle in its presentation, but a regular check-up is advised when there is unexplained intestinal discomfort and or swelling of the abdomen. Ultrasound has not proven effective in detecting cancer in low-risk groups. Currently there are no blood tests or radiological investigations that can be used to test for ovarian cancer.
With this type of cancer, screening can only be initiated once there are symptoms. Most common of these are abnormal vaginal bleeding and bleeding after menopause; in addition, high-risk women are often obese, hypertensive and diabetic. It’s important for the gynaecologist to determine what a normal cycle is for a particular individual.
There are tests to confirm the presence of suspected cancer: ultrasound measurement of the uterus and, often, testing a sample of the uterine lining can be diagnostic. Treatment and prognosis is dependent on the stage of cancer and the need for adjuvant treatment such as chemotherapy or radiation
Cancer of the cervix is the only cancer that has a screening test that, if applied to a large portion of the population, would make a significant difference in incidence and prevalence. There is a premalignant stage that can be detected and treatment initiated. The Pap smear is a fairly simple test that has reasonable sensitivity and specificity. The World Health Organization (WHO) recommends screening in resource-constrained countries like South Africa to be done at age 30, 40 and finally 50. Currently, in the US the Pap test is recommended every three years, rather than annually. The aim of the Pap smear is to detect abnormal cells before they progress to cancer. The current rate of HIV infection has been linked to an increased risk in the development of cervical cancer and perhaps the rapid progression and earlier onset of disease.
Currently the test can only be performed by a healthcare practitioner. It requires an internal examination of the cervix and cells are collected for cytological evaluation. The result can range from normal to degrees of abnormal, where treatment may vary from repeat smears one year later to surgical intervention. Surgery may be minimal, taking the form of a cone biopsy, or more radical, such as a hysterectomy. (In the near future women may be able to perform the test themselves and just hand the specimen in at the pathology lab and wait for results!)
Medical science has progressed to a point where we now know what can cause cervical cancer and we can perform specific tests to identify the culprit and mould treatment on the presence of the specific sub-type of Human Papilloma virus (HPV). Certain strains of HPV have been identified as high risk positively linked to the development of squamous cell cancer, while others have no link and some pose a significant risk. Like many viruses there is now a vaccine for the prevention of cervical cancer. A few companies are making these vaccines, which are used to target the very high-risk sub-types and some of the other high-risk groups. The aim is to produce an innate immunity to HPV and thus to enable the body to defend itself against a cancer-causing virus. In South Africa, there has been a roll-out of the vaccine to young, sexually naive girls around the age of 14 years, with boosters a few months apart. Strategies for the future may include vaccinating young boys and even young adults.
Other types of cervical cancer are rare and only make up about five percent of the total, but they often carry a worse prognosis and follow a more aggressive progression.
This falls outside the scope of gynaecological practice, but is important enough to justify a mention. Unfortunately, screening is poorly done and tests are expensive. Regular mammograms are advised, but self-breast examination has also been useful. Currently, it is recommended that mammograms be undertaken every two years after the age of 45.
Vaginal and vulval cancers are rare and there is no screening test available. Self- examination and regular check-ups are recommended.