To understand Pap test results, it's important to know that the cells that line the cervix and the ones most often "scraped" in a Pap test are squamous cells, and that roughly 90% of cervical cancers occur in squamous cells as squamous carcinomas. When the glandular cells on the inside of the cervix become cancerous, these cancers are known as adenocarcinomas.

Results that do not require follow-up are reported as within normal limits or benign cellular changes.

Overall, about 1 in 10 Pap tests come back with abnormal results, but most of these are due to inflammation and not to a precancerous or cancerous change.

When the Pap test detects abnormally inflamed tissue, 2 different reporting systems are used to detail the changes, which will be reported either as atypical squamous cells of undetermined significance (ASCUS) or atypical dysplasia. These are followed with treatment for concurrent infection, and either repeat Pap smears until the inflammation settles down, or a colposcopy (a procedure in which the cervix is examined through a magnifying instrument, and during which biopsies are taken to determine that there is nothing more significant lurking in the cervix).

When the Pap test discovers inflamed glandular cells, the report will be atypical glandular cells of undetermined significance, or atypical glandular cells. These are followed up with either more Pap smears, or colposcopy and endocervical curretage (a procedure in which a biopsy is taken from higher up in the cervix).

More severe changes are reported either as low- or high-grade intraepithelial lesions (SIL), or as mild, moderate, or severe squamous dysplasia, or as CIN grades I, II, or III.

These are dealt with by treatment of any concurrent infection, watchful waiting, and more frequent repeats of the Pap smear (many milder changes return to normal eventually without requiring treatment), or colpsocopy.

For more advanced changes, therapy can consist of:

  • cryosurgery (freezing the cells)
  • lasers
  • electric cautery
  • a cone biopsy, during which the surgeon removes a cone-shaped slice of cervical tissue
  • hysterectomy in selected cases, if required
Art Hister, MD 
in association with the MediResource Clinical Team