Intrauterine devices, long-used in contraception, may work as a treatment for women with early-stage endometrial cancer, a cancer of the uterus, who want to preserve their fertility, according to a new study.

Endometrial cancer is the most common cancer of the female reproductive system, affecting more than 40,000 women in the United States each year, according to the National Cancer Institute. The usual treatment is a hysterectomy that removes the womb and ovaries, and so prevents women from having children after treatment.

In the new study, the intrauterine devices, or IUDs, released a hormone to inhibit the growth of a particular layer of the womb. The participants, all women under 40, also received hormonal injections to block the development of the cancer. The therapy was effective, and in some cases caused the cancer to disappear completely.

Women who responded well to the treatment — the cancer did not come back or grow — were allowed to have the IUD removed after one year and plan to become pregnant. Nine of the 34 women were able to become pregnant, some more than once. All of the women were still alive at the end of the study 10 years later.

The study was the first to test IUDs as a treatment for endometrial cancer in a clinical trial. The findings are promising but will need to be replicated in a larger group of women before the treatment can be made available to patients, the researchers said.

Preserving fertility

Most women develop endometrial cancer after age 40, but about 3 to 5 percent of cases occur in younger women. In some cases, women who want to have children are prescribed oral medications so they do not need to have a hysterectomy right away. However, these medications can have side effects, including headaches, nausea, vomiting, skin rashes and abnormal uterine bleeding. The IUD treatment avoids these side effects — because the device is close to the cancer site, it can deliver lower doses of hormones.

Dr.  Lucas Minig, a gynecologic oncologist at the Hospital Universitario Madrid Sanchinarro in Spain, and his colleagues tested the treatment on women in Italy between 1996 and 2006. Twenty of the participants had a pre-cancerous endometrial disease, and 14 had early-stage endometrial cancer that was only present in the inner layer or the womb, or the endometrium.

After one year of treatment, 19 of the patients (95 percent) with the pre-cancer showed no signs of the disease, but four needed to be re-treated later. Eight of those with endometrial cancer (57 percent) saw their cancer disappear at 6 months, but two needed re-treatment.

The IUD treatment was about as effective as the oral medications in combating the cancer, but it avoids their harsh side effects, Minig said.

Selecting the right patients

Ultimately, the researchers think patients should be evaluated for this treatment and selected only if doctors were certain they would benefit from it. Down the road, genetic markers may be able to identify which patients would respond well to the IUD treatment.

"Some of [the patients] respond very well and some of them regress to the disease," Minig said. "We think that these patients who did not experience complete response, they probably have some specific genetic mutations in the cancer, that’s why they do not respond to the hormonal treatment," he told MyHealthNewsDaily.

The study will be published online tomorrow (Sept. 29) in the journal Annals of Oncology.