24 Apr Cervical Cancer: Screening and Vaccination
Cervical Cancer: Screening and Vaccination:
Background: The human Papillomavirus (HPV) represents one of the most common sexually transmitted infections that cause cervical cancer. Persistent HPV infection causes most cervical cancer as well as some other cancer like anus, vulva, vegina, penis and oropharynx.
According to WHO ( World Health Organisation) regular screening as well vaccination is essential in the fight against cervical cancer. People living in developing, low or middle income countries are at the increased risk of cervical cancer because they do not have access to screening and treatment services. Cervical cancer is a preventable disease and it can be prevented by simply regular screening and vaccination.
In last few decades cervical cancer mortality rates have fallen in most of the developed countries due to screening programmes. However mortality rate in most of the developing countries remain unchanged or risen due to either limited access to health services or mainly due to lack health education and awareness.
Vaccination: For primary prevention, two vaccines, Gardasil (quadrivalent) and Cervarix (bivalent) have been introduced in India for vaccinating young adolescent girls between ages 9–13 and/or 13–26 years. The HPV vaccines prevent infection with certain species of HPV associated with the development of cervical cancer or genital warts.
The quadrivalent vaccine protecting against human papilloma virus (HPV) types 16/18/6/11 was licensed in 2006, and the bivalent vaccine protecting against infection with HPV-16/18 was licensed in 2007. Both vaccines protect against the oncogenic varieties of HPV-16/18 that cause 70% of all cervical cancers and precancers, as well as many cancers of the vulva, vagina, anus, and throat (Human papillomavirus vaccines: WHO position paper. 2014 Oct;89,43:465–91). The nonavalent vaccine protecting against HPV types 16/18/6/11/31/33/45/52/58 was approved by the USA Food and Drug Administration in December 2014 and can provide a protection against almost 90%.
Even after HPV vaccination, screening test is recommended at regular interval, because the available vaccines do not protect against all HPV types that can cause cervical cancer, girls vaccinated against HPV will still require cervical cancer screening later in their lives.
Two screening tests can help prevent cervical cancer or detect at early stage. (i) The Pap test is recommended for women between ages 21 and 65. (ii) HPV DNA test along with the Pap test is recommended for 30 years old or older.
According to CDC , you should start getting regular Pap tests at age 21. The Pap test, which screens for cervical cancer, is one of the most reliable and effective cancer screening tests available.
The only cancer for which the Pap test screens is cervical cancer. It does not screen for ovarian, uterine, vaginal, or vulvar cancers. So even if you have a Pap test regularly, if you notice any signs or symptoms that are unusual for you, see a doctor to find out why you’re having them. If your Pap test results are normal, your doctor may tell you that you can wait three years until your next Pap test.
If you are 30 years old or older, you may choose to have an HPV test along with the Pap test. Both tests can be performed by your doctor at the same time. When both tests are performed together, it is called co-testing. If your test results are normal, your chance of getting cervical cancer in the next few years is very low. Your doctor may then tell you that you can wait as long as five years for your next screening. But you should still go to the doctor regularly for a checkup.
If you are 21 to 65 years old, it is important for you to continue getting a Pap test as directed by your doctor—even if you think you are too old to have a child or are not having sex anymore.
Dr. Arif, Ph.D ( Molecular Biology), Department of Biosciences, Jamia Millia Islamia,New Delhi, India.
(http://www.bio-services.org/together-we-can-fight-against-cervical-cancer/)
April 24, 2016
References:
Obstet Gynecol Int. 2015;2015:694560. doi: 10.1155/2015/694560. Epub 2015 Dec 9.
Community Awareness of HPV Screening and Vaccination in Odisha.
https://www.ncbi.nlm.nih.gov/pubmed/26783394