The Pap test has been in use since the 1950s and is a highly successful screening exam for the prevention of cancer. A Pap test's primary purpose is the detection of premalignant cell changes involving the uterine cervix. According to the Agency for Healthcare Research and Quality, participation in a regular screening program reduces a woman's likelihood of developing cervical cancer by over 90 percent.
The Pap Test
A trained health care practitioner obtains a Pap smear as part of the vaginal speculum exam. She collects a sample of the surface lining cells of the cervix with a small brush or paddle. These cells are either smeared directly on a glass slide or suspended in a vial with liquid fixative, and sent to a certified laboratory for microscopic evaluation.
Laboratory Reporting
According to the National Cancer Institute, approximately 94 percent of Pap tests are reported as normal or "negative for intraepithelial lesion or malignancy." The remaining 6 percent show a spectrum of abnormal changes ranging from atypical cells through low grade lesion, high grade lesion and rarely to outright cancer. High grade lesions include those cell changes with a higher risk of progressing to cancer and require further evaluation and treatment. Human papillomavirus infection, which is strongly associated with premalignant changes in the cervix, can also be identified.
Further Evaluation
A diagnosis of high grade lesion on a Pap smear requires a repeat vaginal exam, at which time the physician performs a detailed examination of the vagina and cervix using a magnifying instrument called a colposcope. Visible areas of abnormality are biopsied, and generally the endocervical canal is also scraped to test for abnormal cells extending into the lower uterine segment. The biopsy material is examined microscopically to confirm the presence of a significant lesion and to help determine if treatment is necessary.
Treatment
Further treatment is required when the biopsy reveals a high grade lesion, also called cervical intraepithelial neoplasia or carcinoma in situ. The goal is complete removal of all abnormal surface lining cells. Several techniques are available, including loop electrosurgical excision, or LEEP, cryotherapy, laser ablation, cone biopsy and, in some cases, hysterectomy. The method chosen should be agreed upon during discussion between the patient and her physician, taking into account the biopsy findings, medical history and the patient's desires.
Outcome
According to the National Cancer Institute, adequate treatment of high grade lesions should result in nearly 100 percent control of the disease. Repeat Pap tests and follow-up exams will most likely be performed at shorter intervals for a period of time after treatment to monitor the success of the procedure.
