Researchers at Duke University Medical Center are experimenting with a novel way to treat breast cancer that involves heating the tumor while the breast lies in a pool of water. The therapy, called hyperthermia, is administered immediately after chemotherapy and helps the drugs reach cancer cells quickly and effectively. Hyperthermia worked surprisingly well in an early clinical trial of patients with inflammatory and locally advanced breast cancers. Because only the tumor cells of the breast are heated during treatment, hyperthermia enables physicians to use significantly higher doses of chemotherapy to kill cancer cells while minimizing harm to healthy cells. Chemotherapy, the use of anti-cancer drugs, may be administered to breast cancer patients after surgery to help destroy any remaining cancer cells in the body. Less commonly, chemotherapy is given before surgery to help reduce the size of a breast tumor. Because chemotherapy is a systemic treatment, affecting the entire body, it can damage healthy cells as well as cancerous ones. Therefore, many patients experience temporary side effects from chemotherapy, such as nausea, vomiting, hair loss, or fatigue. Some of these effects, such as nausea or vomiting, can be treated effectively with medications. Researchers know that delivering higher than average doses of chemotherapy to patients with more advanced stages of breast cancer can be effective. However, the intensive chemotherapy can also be toxic to healthy cells. Therefore, Kimberly Blackwell, MD and her colleagues at Duke University Medical Center decided to study the effect of delivering higher doses of chemotherapy only to cancer cells, by using encapsulated chemotherapy and heat to deliver and "melt" the drugs into the tumor tissue. The researchers enrolled 21 breast cancer patients with locally advanced cases of the disease in a 12-week phase I (early phase) clinical trial of hyperthermia (heat therapy), funded by the National Cancer Institute. The treatment, according to Dr. Blackwell and her colleagues, consisted of the following:
By encapsulating chemotherapy doses in liposomes (a type of fat), Dr. Blackwell and her colleagues are able to deliver 30 times more chemotherapy with hyperthermia than with normal chemotherapy. Duke researchers Mark Dewhirst, PhD and David Needham, PhD developed a new generation of liposomes that melt very quickly when heated help the encapsulated chemotherapy reach the cancerous tumor within 20 seconds. The researchers determined that the liposomes melt at 40 degrees Celsius (104 degrees Fahrenheit), which is cool enough that the hyperthermia will not burn the patient's skin during treatment. Thus, the pool of water, or "Jacuzzi" that the breast is placed into is heated to this temperature. (According to Dr. Blackwell, some of the patient's have dubbed the treatment the "booby Jacuzzi)." The preliminary results of hyperthermia are dramatic. In the study, the majority of patients experienced a significant reduction in tumor size. In some cases, hyperthermia completely eliminated the tumors. In 17% of patients, tumors were reduced enough in size so that patients could undergo breast-conserving surgery (lumpectomy) instead of mastectomy. Furthermore, Dr. Blackwell and her colleagues reported that patients tended to experience fewer side effects with hyperthermia, such as nausea and vomiting, than with standard chemotherapy. This is because the drugs were directed right to the tumors. While researchers are just beginning to learn about the possible benefits of hyperthermia in breast cancer patients, Dr. Blackwell and her colleagues believe heat helps treat the disease by:
The researchers plan to continue studying hyperthermia as a method of delivering higher-than-normal doses of chemotherapy to breast cancer tumors.
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