Cervical cancer screening has undergone some very important and significant changes recently. If you are of a certain age, you may remember the old-fashioned Pap tests in which the cervical sample was smeared onto a glass slide and sent to the pathology lab for assessment. I know that when you are on the exam table, the last thing you are thinking about is cytology, but let me just say this. We have progressed to the point in cervical cancer screening where smears are infrequently done and liquid-based cytology is the norm. So, from this point on, I will refer to cervical cancer screening instead of Pap testing. (Read "New Guidelines for Cervical Cancer Screening," from the American College of Obstetricians and Gynecologists, Sept. 2013.)
Cervical cancer screening was developed to examine the squamous cells of the cervix before an advanced stage of cancer occurred. Squamous cells form the external genital skin, as well as the skin of the vagina and the cervix. Infection with high-risk human papillomavirus (HPV), commonly HPV-16 and HPV-18, is necessary for the development of abnormal cervical skin changes and nearly all types of cervical cancer.
There is another type of cervical cancer that does not involve squamous cells.
Adenocarcinoma in situ
Adenocarcinoma in situ (AIS)* represents a pre-cancerous condition that can progress to cervical adenocarcinoma. Cervical adenocarcinoma in situ occurs in the glandular tissue of the cervix and is the condition which leads to invasive adenocarcinoma1. The average age of women who are diagnosed with cervical adenocarcinoma in situ (AIS) is 36.92.
Sadly, in most areas with well-established cervical screening programs, there has been no obvious reduction in deaths due to adenocarcinoma, despite substantial decreases in deaths due to squamous cell cancer of the cervix3. One reason for this concerns the cervical cytology screening process. It is done for squamous cell changes, but may miss glandular cell changes of the cervix. Also, know that these screening tests are not 100% accurate for the detection of abnormal cells. This fact alone underscores the need to see your gynecologist on a periodic basis.
What are the risk factors for AIS?
The risk factors for AIS are HPV infection, prolonged infection with high risk HPV types, HPV-16 and HPV-18 that has been undetected, smoking, a compromised immune system (organ transplant history) and human immunodeficiency (HIV) infection.
What are the signs of AIS?
AIS is found in most women who have no warning sign or symptoms. It is not visible to the naked eye and it is most commonly detected due to an abnormal finding on your cervical cancer screening report. It is considered rare for women to experience abnormal vaginal bleeding.
What can you do to decrease the risk of adenocarcinoma in situ (AIS)?
Infection with human papillomavirus (HPV) is very common in both women and men. Of the more than 100 types of this virus, about 30 are spread from person to person through sexual contact. Some types of HPV cause genital warts, while others cause cancer of the cervix. It is estimated that at least three out of four people who are sexually active will get an HPV infection during their lifetime. There are things you can do to protect yourself against HPV infection. One is to be vaccinated against certain types of HPV4.
The finding that adenocarcinoma of the cervix is primarily related to HPV-16 and HPV-18 and that HPV vaccination has significantly prevented cervical adenocarcinoma in situ in clinical trials may indicate that vaccination is the most promising measure to reduce the risk5. For more information click on this link:
Is there a cure for AIS?
The diagnosis and treatment of AIS is challenging because AIS can extend into the cervical canal. Detection and complete removal can also be difficult. Hysterectomy remains the standard treatment for AIS6. If you have not completed your family and wish to retain your fertility, your gynecologist may perform a procedure referred to as a "conization."***
Long term follow up is required for women with AIS who do not undergo hysterectomy. Post-conization follow-up consists of cervical cytology and testing for high risk HPV types for five or more years.7.
1. S. Poterauer, A. Reinthaller, E. Joura, C. GrimmCurr Obtst GynecolRep (2013) 2:86-93
2. M. Carmen, J,. Schorge, B. Goff, S. Falk; cervical adenocarcinoma in situ. www.uptodate.com 2013
3. S. Poterauer, A. Reinthaller, E. Joura, C. GrimmCurr Obtst GynecolRep (2013) 2:86-93
4. American College of Obstetricians and Gynecologists, Human Papilloma Virus APL 167
5. S. Poterauer, A. Reinthaller, E. Joura, C. GrimmCurr Obtst GynecolRep (2013) 2:86-93
6. S. Poterauer, A. Reinthaller, E. Joura, C. GrimmCurr Obtst GynecolRep (2013) 2:86-93
*Adenocarcinoma in situ: pre-invasive cancer of the glandular cervical cells
** woman-year: 1 year in the reproductive life of a woman
***Conization: a procedure which removes a cone-shaped segment of the cervix.