A Pap test is a routine screening procedure designed to detect changes in cervical cells that could indicate a risk of cervical cancer. During this examination, cells are collected from the cervix and analyzed for abnormalities. An “Atypical Squamous Cells of Undetermined Significance,” or ASCUS, result is a common finding. While “abnormal” can cause concern, an ASCUS result frequently does not point to a serious health issue. It suggests some cells appear atypical, but their exact significance for future health is undetermined.
Understanding ASCUS
ASCUS refers to cervical cells that show minor, atypical changes, but these are not distinct enough to be classified as clearly precancerous or cancerous. Pathologists cannot definitively determine the cause or implications of these cellular alterations, hence “undetermined significance.” ASCUS is the most frequently encountered abnormal Pap test result, representing approximately 2 million out of 3.5 million abnormal Pap results reported annually in the United States.
This classification differs from other abnormal results like Low-Grade Squamous Intraepithelial Lesion (LSIL) or High-Grade Squamous Intraepithelial Lesion (HSIL), which suggest more defined levels of abnormal cell growth. LSIL indicates mild changes, while HSIL indicates more severe changes that could potentially progress to cancer if left untreated. An ASCUS result carries a low risk of indicating high-grade lesions or cancer, with the risk of invasive cancer being between 0.1% and 0.2%.
Common Causes of ASCUS Results
The most frequent cause of an ASCUS Pap test result is an infection with the human papillomavirus (HPV). HPV is a common sexually transmitted infection, and many infections often clear on their own without intervention. Certain types of HPV can lead to cellular changes on the cervix that are detected as atypical during a Pap test.
Beyond HPV, several other non-HPV factors can also lead to an ASCUS result. Inflammation of the cervix, often due to various infections or irritation, can cause cervical cells to appear atypical. This inflammatory response can temporarily alter cell appearance.
Other infections, such as yeast infections, bacterial vaginosis, or trichomoniasis, are also known to induce temporary cellular changes that may result in an ASCUS finding. Hormonal fluctuations, particularly during menopause or pregnancy, can also influence the appearance of cervical cells. Lower estrogen levels in postmenopausal individuals can lead to cellular changes that mimic atypical conditions.
Benign growths or conditions, such as cervical polyps or cysts, can additionally contribute to an ASCUS result. Even factors like recent vaginal douching or sexual intercourse before the test can sometimes lead to an ASCUS result by causing temporary irritation.
Next Steps After an ASCUS Result
After receiving an ASCUS Pap test result, the subsequent steps are guided by a healthcare provider, considering individual factors like age and medical history. A common follow-up is a repeat Pap test, often recommended within 6 to 12 months, allowing time for temporary cellular changes to resolve naturally.
HPV testing is frequently recommended to determine if the atypical cells are linked to an HPV infection. If the HPV test is negative, the risk of significant cervical changes is very low, similar to a completely normal Pap test result, and routine screening may resume, often with another co-test (Pap and HPV) in three years.
If the HPV test is positive, especially for high-risk HPV types, a colposcopy might be recommended. This involves a closer, magnified examination of the cervix using a special instrument to identify any areas of concern. During this procedure, a healthcare provider may take small tissue samples, known as biopsies, for further analysis. Maintaining good overall health, including avoiding smoking and supporting the immune system, can also aid the body’s ability to clear HPV infections or resolve inflammation.