In late 2017 a new screening program for cancer of the cervix (neck of the womb) will replace our current Pap smear screening.
For many years we have depended on using the Pap smear to check for abnormal cells that may lead to the possible development of cervical cancer. It is well known that this form of screening had its limitations. The interpretation of the smear test could be affected by many factors not least of all vaginal infection, changes due to menopause and so on.
Over time, the role of the human papillomavirus or HPV in the causation of cervical cancer has become clearer. Most cervical cancers are now believed to be due to the changes brought on by the HPV virus. It is also clear now that there are many types of HPV virus but only a specific number are important in this process. They have been called the high risk group of HPV. Even within this group there are viruses of different risks. The two most important are HPV 16 and 18. The others are classified as the “other “high risk HPV.
HPV is a sexually acquired infection. Current research suggests that HPV infection is common in the younger age population. However, in most, their immune system is able to clear the HPV. Furthermore, it normally takes a long time measured in years, from infection through to development of cancer. There are many changes that can be detected long before cancer occurs. Treatment of these precancerous changes are usually successful in preventing cancer.
In Australia, there was commenced an immunisation program using the vaccine Gardasil for teenagers and young adults. The vaccine comprised 4 HPV viruses including HPV 16 and 18. It has been a successful programme and has led to a reduction in the incidence of HPV infection in the community. This in turn led to a concomitant reduction in the incidence of abnormal cells found on smear testing. Next year a new vaccine with 9 HPV viruses will become available and will provide improved protection.
Given these findings and the success of the HPV vaccination program, it is now planned that a new cervical screening program be instituted from late 2017 onwards. The program will use detection of high risk HPV as the primary trigger for further testing.
There are significant differences from the current regime. Some of these are:
- Screening will commence at age 25 years.
- If on the first screen, high risk HPV is not detected, the tests will be scheduled at 5 year intervals unless such HPV is detected.
- If ongoing screens are all negative then final testing will occur between the ages of 70 -75 years of age
Women can be offered self-testing if they wish. A sampling kit and instructions can be given to those women who wish this. - If high risk HPV is detected, the pathology laboratory will do a smear test from the specimen sample they have received from the doctor. Further management will depend on the type of HPV detected and the smear test results. HPV 16 and 18 will trigger more intensive testing due to their higher risk nature.
- Depending on the abnormalities detected, it is likely that the woman will need to be referred to a Gynaecologist for further management. This management will involve a colposcopy which allows closer assessment of the vagina and cervix. A biopsy may need to be taken and then depending on those results, a future plan of management will be developed for her.
It is important to understand that whilst cancer of the cervix not due to HPV is uncommon, it can develop in a small percentage of women. Therefore, should a woman develop abnormal symptoms like bleeding with sex, irregular bleeding etc., she should seek attention despite having had a negative HPV result.
UPDATE:
Effective as of 1.12.2017, the new cevical screening program has commenced.