Deep-Focused Heat Kills Tumors,
Leaves Surrounding Healthy Tissue Unscathed

Minimally-invasive procedure may represent breakthrough cancer technology

by Kimberly Chapple

Celsion Corp. (formerly Cheung Laboratories), Columbia, Maryland, develops medical treatment systems primarily to treat cancer and benign prostatic hyperplasia (BPH) using minimally-invasive, focused-heat technology.

Celsion's Breast Cancer Treatment System

The first generation of equipment that used heat to kill tumors was actually produced in the late 1980s. "It was based on the technology of microwave ovens, which was all that was available at that time," says Celsion CEO Spencer Volk. "The whole industry was using that kind of basic technology, which worked pretty well on topical tumors. But there wasn't a way of focusing the heat inside the body and not burning your skin or the surrounding healthy tissue." If you can get the temperature high enough -- and it doesn't actually have to be very high -- say 117°-118°F -- you kill cancer cells forever, and those cells cannot come back. So the question, according to Volk, was how do you get heat into a body without burning the person?

Military radar technology applied to deep cancers

The answer may lie in proprietary, patented, adaptive phased array (APA) technology, which makes optimum use of microwave energy to heat and kill cancer cells. Originally developed by the Massachusetts Institute of Technology for use in spaceborne radar surveillance systems for the Department of Defense's Star Wars project, the technology was first designed to target radar signals on incoming missiles while nullifying enemy jammers. Celsion acquired the technology and applied it to cancer treatment, accurately focusing microwave heat on tumors while nullifying the microwaves that would heat a patient's skin or healthy tissue. While the tumor is destroyed, there is no burning or overheating of the skin and surrounding tissue.

The thermotherapy systems are designed to be used alone for treating breast cancer, and in conjunction with radiation or chemotherapy for prostate, lung, liver, and other deep cancers. By concurrently heating tumors and applying either radiation or chemotherapy, the technology can double the complete response rate of tumors (the percentage of cases in which the cancer lesion is eliminated and the cancer does not reemerge -- usually measured over a 2-year period). Preclinical studies have indicated the possibility that the treatment will be non-toxic and side-
effect-free.

For BPH treatment, the company is using a patented transurethral catheter technology, which incorporates microwave heating and balloon compression. It is designed to provide immediate relief of urinary obstruction and long-term symptom control without subsequent catheterization.

Breast cancer treatment

According to the American Cancer Society, breast cancer is the most prevalent cancer for women in the U.S., with approximately 180,000 new cases diagnosed each year. Early stage breast cancer accounts for two-thirds of the breast cancers in the U.S. today. Presently, this form of breast cancer is treated via mastectomy, the removal of the entire breast, or via lumpectomy, the removal of the tumor and surrounding tissue. In lumpectomy, the area at the edge of the removed tissue is examined for the existence of cancerous cells, and if any are found, the lumpectomy procedure is repeated. Full breast radiation usually follows in order to destroy any cancer cells that may not have been captured by the surgical procedure or that may have been spread during the procedure.

The Celsion Breast Cancer Treatment System uses heat alone to ablate breast tumors and viable cancer cells in the tumor vicinity. The system's ability to treat tumors of a range of sizes with focused heat provides the potential to help a significant percentage of breast cancer patients. It is intended for use prior to lumpectomy to completely destroy the cancerous tissue, making the surgery safer and reducing the size of the lumpectomy procedure. This would allow surgeons to remove a small, dead tumor rather than a live tumor as in current lumpectomies. The system is also designed to treat patients with medium or large breast tumors, and will shrink (downstage) the tumors sufficiently to allow breast conserving lumpectomies to be performed instead of complete mastectomies.

"After seeing the results of the Phase I study, I look forward to beginning Phase II studies with the ultimate objective of providing breast conserving options to my patients," says Dr. Robert Gardner, principal investigator and director of the Center for Breast Surgery (FL) of HCA. Last month, the FDA approved Celsion's application to proceed with Phase II at the Center for Breast Surgery, Johns Hopkins Hospital, Massachusetts General Hospital, UCLA Medical Center and Hammersmith Hospital (London).

Initially, radiation therapy and chemotherapy will follow the lumpectomy as in the current practice. However, the company expects that, upon FDA approval, Celsion thermal ablation will provide a safe and thorough treatment in stand-alone mode, eliminating the necessity for radiation or chemotherapy and their debilitating side effects. (The company reports this alteration in standard practice requires additional clinical trials for FDA clearance.)

Benign prostatic hyperlasia

Celsion's patented benign prostatic hyperplasia (BPH) system overcomes the problem of enlarged prostates in two ways. First, a special balloon catheter delivers transurethral microwave heatingimal tests a natural biological stent in the urethra, and is expected to provide immediate relief of urinary obstruction in clinical trials.

The system's advantage is that it provides a single, in-the-office procedure designed to provide immediate relief from obstruction. It is also designed to provide long-term symptom control without subsequent catheterization. The non-surgical urethroplasty procedure is expected to provide BPH patients immediate urine-flow relief by forming the biological stent, a feature absent from all other current commercial BPH thermotherapy systems. Since Celsion's system uses lower temperatures than other thermotherapy systems, it is expected to provide its treatment benefits without side effects.

In the pipeline

The Celsion Prostate Cancer Treatment System operates in much the same way as the Celsion BPH treatment system. The system is minimally invasive and uses microwave applicators designed to safely eradicate prostate cancer without harming surrounding healthy tissues. The prostate cancer treatment system is designed to increase the effectiveness of radiation seed implant therapy by about a factor of two without any added side effects.

The company is currently at work on a prototype of a deep cancer treatment system that also uses the focused heating adaptive phased array method and is designed to target tumors in the liver, rectum, cervix, pancreas, lung and other areas deep within the torso. The system is designed to increase the effectiveness of radiation therapy and chemotherapy by about a factor of two without any added side effects. Once the machine is completed, clinical trials will begin at Duke and Northwestern Universities, the latter of which is presently conducting pre-clinical research on the adaptive phased array technology under a licensing agreement with MIT.