Swedish women are regularly called in for cell tests. In cases where severe changes in cells are discovered, the outer layer of the portio vaginalis is removed in an operation. Annually some 10,000 women in Sweden undergo this operation for cell changes in the cervix. If the cell changes are left untreated, there is a great risk of developing cervical cancer or vaginal cancer.

But despite this operation and subsequent monitoring, these women still face 2.5 times the risk of developing cervical cancer or vaginal cancer compared with other women. This is shown in a Swedish study now being published in British Medical Journal.
“It is remarkable that the risk of cancer continues to be elevated even though the sections of the tissue where cervical cancer usually starts have been removed,” says the study’s lead author, Björn Strander, a doctoral candidate at the Sahgrenska Academy and chief physician at the Oncology Center for the Western Sweden health-care region.

The researchers have been able to monitor women for more than 25 years after treatment and have found that the risk does not decline substantially after a long period. The elevated risk was greatest among women who were over the age of fifty when they underwent treatment for the cell changes.
“The treatments are successful since only about one percent of these women develop cancer, but it appears that women have not been monitored carefully enough with cell samples and not long enough after their treatment,” says Björn Strander.

He therefore feels that it is important to review the special follow-up programs that are offered following treatment for cell changes.

The study was carried out with the aid of the Swedish Cancer Register. This register includes severe cell changes that have not developed into cancer. A total of 132 493 women who have been treated for such cell changes could be followed for an average of 17 years, some of them as long as 40 years.

“Thanks to well-managed and comprehensive registers, we in Sweden can perform epidemiological studies and uncover interesting results that would not be possible in most other countries. They help Sweden maintain its prominent position in medical research,” says Pär Sparén, professor of medical epidemiology at the Karolinska Institute, and co-author of the study.

The study will be included in Björn Strander’s doctoral dissertation, to be submitted in January at the Sahlgrenska Academy. The dissertation is about improving the protection against cervical cancer in Sweden.

FACTS ABOUT CERVICAL CANCER
Women between the ages of 23 and 60 are regularly called in for cell testing. Participating in these check-ups provides good protection against cervical cancer. When a woman develops cervical cancer, the most common reason is that she did not take part in the check-ups, but it does sometimes happen that women who did participate develop cancer. In Sweden cervical cancer has become uncommon thanks to the recurrent cell sample checks, but nevertheless some 130 women die of the disease each year. In major sections of the third world, cervical cancer is the leading cause of premature death among women.

Journal: British Medical Journal
Name of article: Long term risk of invasive cancer after treatment for cervical intraepithelial neoplasia grade 3: population based cohort study
Authors: Björn Strander, Agneta Andersson-Ellström, Ian Milsom, Pär Sparén

For more information please contact:
Doctoral candidate Björn Strander, Department of clinical Sciences, cell phone: +46 (0)704-97 22 26, e-mail: bjorn.strander@oc.gu.se