Changes in cells vary, but the most significant changes are called ‘dysplasia’, which is an abnormal change in the size and shape of cells. Although not cancer, dysplasia may develop into a cancerous state over a lengthy but unpredictable period of time if left untreated. Dysplasia in endometrial cells of the cervix is classified as ‘cervical intraepithelial neoplasia, which has mild to severe stages denoted by CIN1 (mild), CIN2 (moderate), and CIN3 (severe). Additionally, other minor abnormal changes in these cells are also observed, but do not necessarily indicate a precancerous nature.
Human papillomavirus (HPV) causes CIN1; 4 in 5 cases of HPV will not need treatment within 12 months. Cases of CIN2 and CIN3 are too dangerous to leave untreated and it is usually recommended by a professional to have the cells removed.
These are possible results a Pap smear may entail and what they mean:
[CIN1] Atypical squamous cells of undetermined significance (ASCUS):
These thin and flattened cells are the most common abnormal finding in Pap smears. They grow on the surface of a healthy cervix and are quite ambiguous in suggesting the presence of precancerous cells or if cells are benign in nature. However, further liquid based tests can be used to analyse if there are types of HPV present, which are known to assist the development of cancer.
[CIN1/CIN2] Squamous intraepithelial lesion (SIL):
An abnormal growth of cells that may be precancerous, which reside on the surface of the cervix. If these cells collected by the Pap smear suggest a precancerous nature and display subtle changes, the full development of cervical cancer is most likely years away this is lowgrade SIL (LSIL). However, if the cell changes are substantial this known as highgrade SIL (HSIL) there is a high chance the cancer will be fully developed soon; this involves further testing.
Atypical glandular cells:
These are uncommon mucus producing glandular cells that grow within the uterus and opening of the cervix. Whether or not these cells are cancerous is rather ambiguous, but they have been associated with severe lesions or cancer. Further testing is required to find the source and effect of these cells.
[CIN3] Squamous cell cancer or adenocarcinoma cells:
Extremely abnormal cells collected from the Pap smear that signify a strong presence of a cancer. Squamous cell cancer appears in flat surface cells of the cervix or vagina; adenocarcinoma is cancer appearing in glandular cells. Immediate evaluation is undergone if these cells are found.
If a Pap smear is positive, a colposcopy may be performed, which involves examining the tissues of the cervix, vagina and vulva with a colposcope. A colposcope is a special instrument that uses lenses to magnify the areas, helping distinguish abnormal from normal tissues. A biopsy, which involves taking a tissue sample, may also be performed and delivered to a laboratory for accurate analysis and conclusive diagnosis.