11/11/2011 12:12 pm ET | Updated Jan 11, 2012

Vaccine Shows Promise At Halting Spread Of Breast, Ovarian Cancers

A new vaccine has proved promising at halting the spread of metastatic breast and ovarian cancers, according to a new, small study.

The poxviral vaccine seemed to be effective at completely ridding one person involved in the study of cancer, WebMD reported.

"In January, it will be four years [for her]," study researcher Dr. James Gulley, of the National Cancer Institute, told WebMD.

However, the vaccine wasn't as overwhelmingly successful in the other 25 patients -- for some of those people, the vaccine seemed to extend the amount of time before the cancer progressed by a few months, WebMD noted.

The Los Angeles Times reported that the vaccine was given monthly to the women (12 of whom have breast cancer, and 14 of whom have ovarian cancer).

The Clinical Cancer Research study was small, and didn't compare the results of the vaccine with what would have happened if women didn't have any treatment, the LA Times pointed out.

But still, the results are promising, especially in the woman whose cancer seemed to go away after receiving the vaccine, TIME reported.

TIME explained:

One woman with breast cancer who had already undergone a lumpectomy, radiation, chemotherapy and a hysterectomy that included removal of her ovaries showed a complete response to the vaccine; after three years, tumors that had spread to her lymph nodes had regressed. "We don't need a control group to say [these results] are a good thing," says Gulley. "We don't see this in breast cancer. We don't see tumors spontaneously going away."

When breast cancer spreads, it's most likely to spread to the lungs, liver and bones, according to the National Cancer Institute. And when ovarian cancer spreads, it's most likely to spread to the peritoneum (a membrane that lines the wall of our abdomen), liver and lungs.

Metastatic cancer is notoriously hard to treat -- the National Cancer Institute explains why:

Although some types of metastatic cancer can be cured with current treatments, most cannot. Nevertheless, treatments are available for all patients with metastatic cancer. In general, the primary goal of these treatments is to control the growth of the cancer or to relieve symptoms caused by it. In some cases, metastatic cancer treatments may help prolong life. However, most people who die of cancer die of metastatic disease.

Recently, researchers from the University of Pennsylvania have found that a leukemia treatment seems to be extra-effective at destroying leukemia cells in three patients who have the disease.

And this summer, researchers from Leeds University developed a vaccine that seems to be effective at shrinking prostate cancer tumors in mice. That study, published in the journal Nature Medicine, suggests that the method could be used on other cancers, too, Reuters reported.