A thin layer of tissue, composed of cells, covers the cervix. As cervical cells develop, the cells on the bottom layer move to the surface of the cervix. Sometimes, during cellular development, cervical cells may become damaged or abnormal. When this occurs, these cells develop in an abnormal way and sometimes require removal to prevent cervical cancer from developing.
Cervical dysplasia or cervical intraepithelial neoplasia (CIN) are precancerous cervical changes that may appear on the cervix. If these type of changes are detected on your Pap test, they will be graded as mild (CIN 1), moderate (CIN 2), or severe (CIN 3.) CIN 1 usually requires no treatment as it most often subsides on its own. CIN 2 and CIN 3 are more serious and require further evaluation and treatment.
Having regular Pap smear test significantly reduces the chance that cervical cancer will ever develop.
We now know that the cause of virtually all cases of cervical cancer is infection with the human papillomavirus (HPV). While there are numerous types of HPV, only a few types can develop into cervical cancer, as well as vulvar cancer and vaginal cancer. We also know that certain other types of HPV may develop into genital warts.
HPV is a common type of sexually transmitted disease (STD.) Women younger than 20 face a greater risk of contracting HPV than older women. In most cases, the immune system quickly attacks HPV, which helps the HPV infection heal itself. Other women are not so lucky and HPV does not heal itself – a small number of these women will develop CIN. The development of CIN is more likely to occur in older women who have had HPV for a long time. Women who smoke and have HPV face twice the risk of developing CIN than women who do not smoke. The good news is that if you have regular Pap smear tests, it’s unlikely that severe precancerous changes will occur because it takes many years for these types of cervical cell changes to develop into cervical cancer.
The most common system for describing Pap smear test results is the Bethesda System. The Bethesda System uses a number of terms to relate the results. Squamous intraepithelial lesion (SIL) describes precancerous changes in cervical cells. The word squamous describes irregular-shaped, flat cells. Using this system, your Pap smear test results may be:
- Normal – This is what we all hope for when we have our Pap smear tests.
- Atypical squamous cells of undetermined significance (ASCUS) – This is the most common abnormal Pap smear test result indicating the presence of cervical cell changes. While this is most often an indication that HPV is present, it can mean that precancerous changes have occurred.
- Squamous intraepithelial lesion (SIL) – This term describes abnormal cervical cell changes that may be a sign of precancer. SIL is either low grade (LSIL) or high grade (HSIL.) LSIL or HSIL refers to the grade of dysplasia and CIN. LSIL is indicative of either the presence of HPV or mild precancerous changes; this is a common type of abnormal Pap smear result and one that normally goes away without any intervention. HSIL, on the other hand, indicates more serious cervical cell changes. The most severe type of HSIL is carcinoma in situ (CIS.) CIS is the type of HSIL most likely to progress to cervical cancer.
Atypical Squamous cells, cannot exclude HSIL (ASCH) – This Pap smear test result means there is uncertainty about whether HSIL is present. This result requires further tests.
Atypical glandular cells (AGC) – This term implies precancerous changes to the upper cervix or uterus. Of course, this requires further testing.
Cancer – Hopefully, you will never get this result from your Pap smear. When this result is given, it means that abnormal cervical cells may have spread deep into the cervix or other nearby tissues. Having regular Pap smear tests can almost guarantee that you will never get a result of cancer.
