Advantages and disadvantages of cervical cytology screening (Pap test)

Screening for cervical cancer has advantages and disadvantages. The standard screening method is cervical cytology, also called “Pap test”. You can choose whether or not have a cytology. Here is some information to help you decide. You can discuss it with your doctor as needed.

Cytologies every 2 to 3 years for women between the ages of 21 and 65 reduce the risk of dying from cervical cancer.

• Of 1,000 women who do not get screened, 10 could die from cervical cancer.
• Of 1,000 women who do get screened, 2 could die from cervical cancer.

Therefore, there are 8 less cervical-cancer-related deaths in the 1,000 women who get screened.

This is due to the fact that:

• Screening helps detect abnormal cells in the cervix, which can develop into cancer. A doctor can remove the parts of the cervix that contain these cells before a cancer develops. In this way, screening reduces the risk of getting cervical cancer.
• If a cancer is already present, early detection due to screening improves the chances of recovery.

Despite the advantages, cytologies are not entirely perfect.

• An abnormal cytology means that there have been some changes to the cells lining the cervix. The woman must therefore undergo an exam called a colposcopy. Receiving an abnormal cytology result and waiting for colposcopy results can lead to anxiety. In most cases, colposcopy results are normal.
• A colposcopy can be uncomfortable and sometimes painful.
• A colposcopy can reveal the presence of abnormal cells. These cells can develop into cancer, but not necessarily. As it is impossible to know in advance, the area of the cervix that contains these abnormal cells must be removed as a precaution. This may result in some women having a part of their cervix removed “for nothing”. Such cases most often affect younger women, as shown in the following tables:

  Number of women who undergo a colposcopy as a result of screening

  Woman’s age at the time of screening	Number of women who have a colposcopy (of 1,000 women screened)
  20-29 years	60
  30-39 years	26
  40-49 years	17
  50-59 years	10
  60 years and older	6

  Number of women who must have a part of their cervix removed after a colposcopy

  Woman’s age at the time of screening	Number of women who must have a part of their cervix removed due to the presence of abnormal cells	Number of women who have a part of their cervix removed “for nothing” because abnormal cells would never have developed into cancer
  20-29 years	13 (of 60 who underwent a colposcopy)	9 (of 13 who had a part of their cervix removed)
  30-39 years	7 (of 26 who underwent a colposcopy)	5 (of 7 who had a part of their cervix removed)
  40-49 years	4 (of 17 who underwent a colposcopy)	3 (of 4 who had a part of their cervix removed)
  50-59 years	2 (of 10 who underwent a colposcopy)	1 (of 2 who had a part of their cervix removed)
  60 years and older	1 (of 6 who underwent a colposcopy)	Less than 1

• The removal of a part of the cervix can slightly increase the risk of giving birth prematurely for subsequent pregnancies. For example, a woman who has this procedure could give birth before the 34^th week. (A pregnancy normally lasts 40 weeks.) Of 100 women who have a part of their cervix removed, 1 is at risk of giving birth prematurely.
• Cytologies are not always completely accurate. Sometimes, test results can appear normal even if there is a cancer or abnormal cells in the lining of the cervix. Some women who receive normal cytology results may therefore be wrongly reassured.