A new method for treating breast cancer by delivering chemotherapy through the nipple offers a highly targeted, less toxic approach than traditional treatments, according to a new study. But many breast cancer specialists caution that it's too early to know whether the treatment will work for large numbers of women.
Researchers at the Johns Hopkins Kimmel Cancer Center in Baltimore tested the method on rats and also in a very small group of human patients -- 17 women with breast cancer. In their report, published today in the journal Science Translational Medicine, the researchers reported that delivery of chemotherapy drugs through the nipple had been highly effective in treating small, early-stage tumors, and produced none of the side effects that accompany traditional chemotherapy.
The method is designed to deliver chemotherapy drugs directly to the breast tissue -- a branching treelike system of milk ducts inside the breast -- where many cancers form. This direct delivery offers a highly localized treatment compared to drugs given intravenously or taken orally, and avoids the extreme approach chosen by some women of completely removing their breasts.
"You can give more much effective doses if the drug stays where it's supposed to, in the breast," said Dr. Vered Stearns, co-director of the breast cancer program at the Kimmel Cancer Center and an author of the study. "The women in our study that got the treatment directly into the breast through the nipple had a very high concentration of the drug in the breast and very low concentrations in the blood."
Saraswati Sukumar, a cancer biologist at Johns Hopkins, investigated how to target the cancer cells that lurk in this system of ducts in mice and rats.
"We wanted to see whether this would stop the cancer in its tracks," Sukumar said.
According to the study, it did. In 10 of the 14 rats tested in one portion of the study, the chemotherapy drugs eliminated tumors in the breast tissue. But Sukumar said she was most intrigued by the preventive effects the therapy seemed to have on the animals. When the chemotherapy drugs were injected into four of the rats' mammary glands, it seemed to prevent tumors from forming in the remaining eight mammary glands.
"Its like putting Drano through a clogged ductal system. The entire system will be cleared of both visible and invisible cancer cells," Sukumar said. "You're treating and also preventing the cancer."
In human patients, the researchers reported that treatment produced virtually no side effects, other than moderate nipple pain and a heaviness in the breast that lasted for about an hour, according to Stearns. The absence of intolerable side effects contrasts starkly with the effects of other chemotherapy and radiation treatments.
Stearns said the treatment could possibly offer women at high risk for breast cancer a more tolerable approach to prevention. Rather than waiting for disease to develop or even having their breasts removed entirely, they could have chemotherapy drugs administered through the nipple into the ducts, where they would kill precancerous cells.
"Think of colonoscopies. If you see a polyp, you treat it and hopefully prevent future colorectal cancer," Stearns said. "With this treatment, a woman will be having a mammogram, and based on our studies, this procedure would give her the option of having an intact breast with very few treatment side effects."