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Key Words

Cervical cancer, cervical intraepithelial neoplasia (CIN), cervical dysplasia. (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary ³.)

Summary

Surgery to remove abnormal cells on the cervix can prevent a precancerous condition known as cervical intraepithelial neoplasia (CIN) from progressing to cervical cancer. In some cases, however, abnormal cells are not completely removed, leaving an “involved margin.” A combined analysis of previous studies has shown that after surgery for CIN, women with involved margins have a substantially higher risk of the disease coming back than women whose margins were clear of abnormal cells.

Source

Lancet Oncology, November 2007 (see the journal abstract ⁴)
(Lancet Oncol. 2007 Nov;8(11):985-93. Epub 2007 Oct 24)

Background

Cervical intraepithelial neoplasia (CIN) – also called cervical dysplasia – is the abnormal growth of cells on the surface of the cervix, or opening of the uterus. It is not cancer, but it is considered a precancerous condition. Without treatment, one third to one half of cases of CIN may progress to cervical cancer. The purpose of cervical screening (i.e., the annual Pap test) is to detect precancerous changes like CIN and treat them before they progress. When CIN is found early and properly treated, it can often be cured.

The most common treatment for CIN is surgery to remove the abnormal cells. Sometimes, however, abnormal cells remain in the “margin” - the edge or border of the area where cells were removed. Whether “involved margins” - the presence of abnormal cells in the margin after surgery - increases the risk of a recurrence of CIN has been a matter of controversy.

The Study

To find out whether involved margins increased the risk of a recurrence after surgery for CIN, researchers conducted a meta-analysis, a type of study in which data from numerous other studies are combined and summarized. The meta-analysis described here included data from 66 studies involving more than 35,000 women treated for CIN. The study’s principal investigator was Sadaf Ghaem-Maghami, M.D., of Imperial College in London, England.

Results

A median of 24 percent of the women in the studies had involved margins after surgery. Overall, 18 percent of women with involved margins developed moderate or severe CIN after surgery compared with three percent of those whose margins were clear of abnormal cells.

Comments

“Incomplete excision of CIN exposes women to a substantial risk of high-grade post-treatment disease,” the authors conclude. They recommend that every effort be made to avoid incomplete excision and that women with involved margins be closely followed for at least 10 years.

This study is a well-conducted meta-analysis and its large size (more than 35,000 women) is a strength, says Ted Trimble, M.D., of the National Cancer Institute’s Cancer Treatment and Evaluation Program. He endorses the recommendation for close long-term follow-up of women with involved margins.

“These findings confirm that there is a risk of persistent disease in women who have positive margins after surgery,” he says. Positive margins can occur when doctors limit the extent of surgery to reduce the risk of postsurgical complications, he explains. The surgery can cause postoperative bleeding and may make it more difficult for a woman to become pregnant. In addition, women who do become pregnant after surgery may miscarry or deliver prematurely.

Glossary Terms

Growth of abnormal cells on the surface of the cervix. Numbers from 1 to 3 may be used to describe how abnormal the cells are and how much of the cervical tissue is involved. Also called CIN.

The lower, narrow end of the uterus that forms a canal between the uterus and vagina.

Removal by surgery.

A term used to describe cells that look abnormal under a microscope. These cells are more likely to grow and spread quickly than cells in low-grade cancer or in growths that may become cancer.

The edge or border of the tissue removed in cancer surgery. The margin is described as negative or clean when the pathologist finds no cancer cells at the edge of the tissue, suggesting that all of the cancer has been removed. The margin is described as positive or involved when the pathologist finds cancer cells at the edge of the tissue, suggesting that all of the cancer has not been removed.

A statistics term. The middle value in a set of measurements.

A procedure in which cells are scraped from the cervix for examination under a microscope. It is used to detect cancer and changes that may lead to cancer. A Pap test can also show conditions, such as infection or inflammation, that are not cancer. Also called Pap smear and Papanicolaou test.

A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.

The small, hollow, pear-shaped organ in a woman's pelvis. This is the organ in which a fetus develops. Also called womb.