Is raising age for tests a concern?
The Ministry of Health is raising the age women begin having cervical smear tests, used to detect human papilloma virus (HPV), from 20 to 25.
Q: Are the Ministry of Health’s changes to cervical cancer screening any cause for concern? A: Associate Professor Merilyn Hibma, of the department of pathology at the University of Otago, responds:
Cervical cancer may occur when there is a long-term infection with human papillomavirus (HPV).
There are many types of HPV that infect our skin. It is only when the infection is with a ‘‘cancercausing’’ HPV, and when the infection is not cleared by our body’s immune system, that there is a risk of cancer developing.
The HPV infection causes changes to the cells of the cervix that can be detected by the ‘‘pap’’ smear. These changes indicate a greater risk that cancer could occur and, depending on the type of change, are monitored or treated.
The HPV vaccine protects against the two major cancercausing virus types – 16 and 18. Vaccination should be administered prior to sexual activity and works best in younger women.
The vaccine is very effective for the two cancer-causing types, but vaccinated women are still at risk of infection with other types. Also, the vaccination rates in New Zealand are relatively low, and unvaccinated women are particularly at risk of developing cellular changes that may lead to cancer.
The Ministry of Health is planning to use a new test that identifies HPV DNA in the future. This test is very sensitive for detecting HPV, but a positive test is not always associated with cellular changes or persistent infection, particularly in women under 25.
By commencing screening after 25 years of age, the risk of unnecessary treatment in young women is reduced.
An effective screening programme to prevent cervical cancer requires participation.
With good participation in screening by women, this change in age of commencement of screening will not reduce the effectiveness of the screening programme in New Zealand. ❚ Source - Science Media Centre