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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:
- Traditional chemotherapy (typically through infusion).
- A CAT scan to determine the precise location of the breast
cancer tumor.
- Insertion of a small tube (catheter) inside the tumor (a thermometer was placed inside
the catheter during hyperthermia to monitor the tumor's temperature).
- Hyperthermia: After the higher-dose encapsulated chemotherapy was administered, the
patient lay on a specially designed table (similar to a massage table) for one hour as
radio frequency energy warmed the breast tumor, which was placed in a pool of water.
- The patient received hyperthermia every three weeks for four cycles.
- After all treatments are completed, the tumor was analyzed to determine whether it had
been reduced. Surgery (in some cases, breast-conserving
surgery) were recommended.
- After surgery to remove the tumor, standard chemotherapy and radiation therapy were given to destroy remaining
cancer cells.
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:
- increasing the rate of chemotherapy uptake into a cancerous tumor
- increasing oxygen levels within the tumor
- increasing DNA damage to the tumor
The researchers plan to continue studying hyperthermia as a method of delivering
higher-than-normal doses of chemotherapy to breast cancer tumors.
Additional Resources and References
- The study, "Neoadjuvant chemotherapy and hyperthermia improve tumor reoxygenation
in patients with locally advanced breast carcinoma," was presented on May 18, 2002 at
the annual meeting of the American Society of Clinical Oncology. An abstract of the study
is available on the ASCO website, http://www.asco.org/
- The May 18, 2002 Duke University Medical Center news release, "New Breast Cancer
Therapy at Duke Comprehensive Cancer Center Boosts Drugs' Effects, Dramatically Shrinks
Tumors," is available at http://www.mc.duke.edu/
- To learn more about chemotherapy for breast cancer, please visit http://www.imaginis.com/breasthealth/chemo.asp
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