FAQ - Frequently Asked Questions

General Hyperthermia | BSD-500 | BSD-2000 | BSD-2000 3D/MR

What is Hyperthermia?

Hyperthermia is a type of cancer treatment in which tumors are exposed to elevated body temperatures, between 104˚ and 113°F.  Research has shown that high temperatures can damage and kill cancer cells, usually with minimal injury to healthy tissues. Higher temperatures selectively damage cells that are hypoxic and have low pH, a condition of tumor cells, and not a condition of healthy cells. Hyperthermia has been shown to inhibit cellular repair mechanisms, induce heat-shock proteins, denature proteins, induce apoptosis, and inhibit angiogenesis.

Tumour hypoxia is a situation where tumor cells have been deprived of oxygen. As a tumor grows, it rapidly outgrows its blood supply, leaving portions of the tumor with regions where the oxygen concentration is significantly lower than in healthy tissues.
Heat shock proteins are a family of proteins that are produced by cells in response to exposure to stressful conditions.
Apoptosis is the process of programmed cell death (PCD)
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels.

What is Superficial Hyperthermia?

Superficial hyperthermia approaches are used to treat tumors that are in or just below the skin. External applicators are positioned around or near the appropriate region, and energy is focused on the tumor to raise its temperature.  The BSD-500 shows excellent results in clinical studies on recurrent and progressive Melanoma, Squamous or basal-cell carcinoma, Sarcoma and Adenocarcinoma.

What is Interstitial Hyperthermia?

The BSD-500 can bring therapeutic hyperthermia to solid tumors via catheters placed into the body, usually done during the brachytherapy process.  The BSD-500 delivers energy to a patient using a power source and an array of multiple antennas inserted into the catheters.  RF energy is applied at 915 MHz to provide an optimized heating zone targeted to the tumor region by utilizing the adjustment of phase and amplitude from multiple power sources.

What is Deep Regional Hyperthermia?

The BSD-2000 provides deep regional therapeutic hyperthermia to solid tumors by applying radiofrequency (RF) energy at the frequency range of 75 to 120 MHz. The BSD-2000 delivers energy to a patient using a power source and an array of multiple antennae that surround the patient’s body. The system provides an optimized heating zone targeted to the tumor region by utilizing the adjustment of frequency, phase, and amplitude from multiple power sources. The energy can be focused electronically to the tumor region, thus providing dynamic control of the heating delivered to the tumor region.

How does Hyperthermia work with Radiation Therapy?

Hyperthermia increases the effectiveness of radiation therapy due to the independent cytotoxic effects of hyperthermia combined with its radiosensitizing effects. Hyperthermia increases blood flow, resulting in improved tissue oxygenation and thus increased radiosensitivity. Hyperthermia also interferes with cellular repair of the DNA damage caused by radiation. Hyperthermia damages cells that are hypoxic have a low pH and are in the S-phase of division, which is all conditions that make cells resistant to radiation therapy. The addition of hyperthermia does not usually increase the toxicity of radiation therapy.

How does Hyperthermia work with Chemotherapy?

Hyperthermia used in combination with chemotherapy increases the drug concentration in the tumor region due to increased blood flow, thus raising the effectiveness of cytostatic drugs.  Also hyperthermia has been proven to enhance drug toxicity in cells resistant to many drugs.

Why is it more commonly used in Recurrent Cancer Treatment?

There is a lifetime limit to the amount of radiation a patient can be exposed to.  So doctors must look for alternative therapies when treating cancer that has returned.  This is where clinical trials flourish. It was found that hyperthermia sensitized tumors to radiation treatment allowing Radiation oncologists to treat recurrent cancer with less toxicity.

Is there Clinical Evidence?

Numerous clinical trials have studied hyperthermia in combination with radiation therapy and/or chemotherapy. These studies have focused on the treatment of many types of cancer, including sarcoma, melanoma, and cancers of the head and neck, brain, lung, esophagus, breast, bladder, rectum, liver, appendix, cervix, and peritoneal lining (mesothelioma). Many of these studies have shown a significant reduction in tumor size when hyperthermia is combined with other treatments.

Is it Safe?

The Hyperthermia process does not harm, is non-toxic, and is non-invasive. Most normal tissues are not damaged during hyperthermia if the temperature remains under 111°F. However, due to regional differences in tissue characteristics, higher temperatures may occur in various spots. This can result in burns (9.9%), pain (8.4%), ulceration (3.6%) and infection (1.8%). Perfusion techniques can cause tissue swelling, blood clots, bleeding, and other damage to the normal tissues in the perfused area; however, most of these side effects are temporary. (National Institute of Health)

It may be defined as minimally invasive when used with radiotherapy. In this case, hyperthermia RF antennas are placed in existing catheters that were placed in the body by the Radiation therapy process.

Hyperthermia is almost always used with other forms of cancer therapy, such as radiation therapy and chemotherapy (1, 3). Hyperthermia may make some cancer cells more sensitive to radiation or harm other cancer cells that radiation cannot damage. When hyperthermia and radiation therapy are combined, they are often given within an hour of each other. Hyperthermia can also enhance the effects of certain anticancer drugs.

 

 

BSD-500 Superficial / Interstitial System Questions

Questions specifically related to the BSD-500 Superficial/Interstitial Hyperthermia System

Are there any side effects or complications for head and neck cancer treatment by BSD-500? (Ex: blood vessel rupture, stoke, …)

No there have not been any complications that you have described. If the ear is involved with a tumor, there could be damage to the ear if the tumor is highly involved with the ear. The eye is a sensitive area which has low bloodflow, so you should avoid treating very close to the eye. If there are more specific concerns I can try to respond further. If there is scar area from prior surgeries in the area to be treated, the scar tissue will have less bloodflow and may get to higher temperatures than the normal

When we are setting and adjusting the MA-151 applicator, how to make sure that the tumor location is right?

This small applicator has a heating pattern that is about 2.5cm in diameter and is centered on the applicator. It is generally possible to place the center of the bolus at the center of the tumor.

If the tumor > 3cm, the MA-151 Applicator can’t cover the tumor. Could we exchange the MA-151 to MA-100?

Or what should we do? You will find that a 3cm tumor will still respond well with the MA-151 treatment. You may find that moving the applicator position after 30 minutes at temperature to another position for the last 30 minutes could cover the tumor with heat better. When the treatment is along with radiation therapy, there will normally 5 to 10 heat treatments which allows for different applicator positions as the tumor may be decreasing in volume during the treatment series. The MA-100 can also be used to treat smaller 3cm tumors and the contact with the water bolus. The MA-100 bolus could be placed to have the water bolus only contact a smaller diameter of the surface tissue to confine the heating to a smaller heating zone. Typically for superficial tumors the water temperature is set between 40 to 42degC.

When patients treat with hyperthermia for an hour, they may feel uncomfortable or move. How to make sure that the bolus is attached to the skin surface and the target tumor site?

It is best to place the patient in a comfortable position so that the patient movement is avoided. The operator should be with the patient and observe if there is movement so that the applicator position can be adjusted. Remember that the treatment is heating tissue to a high fever temperature of about 42 to 43degC which would not cause harm to normal tissues.

Could you please give us the protocol and treatment guide for head and neck cancer treatment by BSD-500?

There is no specific protocol that is any different that treatment in other superficial areas of the body. The rate of heating is best limited to between 1 to 2 degrees per minute to maintain patient comfort. Most often the water bolus for tumors involved near the surface is between 40 to 42degC, but can be lower if there is a deeper tumor. If possible temperature sensors can be placed into the tumor using plastic needle/catheters and should be placed along the surface.

HT treatment is preferred to be within 1 hour of the radiation therapy treatment.” How about the chemotherapy combine with hyperthermia? (like Neoadjuvant).

I have attached article #3185 as a current reference for such treatments for educational purposes to respond to your question. If chemotherapy is combined with hyperthermia it is common that the chemotherapy is being circulated in the patient during the heat treatment when the doctor wants to enhance the effect of the chemotherapy by the target tissue being elevated in temperature.

If the patients have fungating wounds or surgical wounds on their breast, could they still treat hyperthermia? How could we dress the wound part when the patients treat hyperthermia?

In such cases where the surface is moist, a thin plastic film layer can be placed on the skin surface. This will allow the attachment of the temperature sensor probes to the plastic film being secured by tape (the edge of the tape is best folded back to form a tab when it is time to remove the probe from the plastic). Surgical wounds on the breast will be scar tissue that will have less bloodflow. This will cause the scar tissue to retain the MW heating and could reach higher temperatures than other tissues. Place temperature sensors at the scar tissue to avoid temperatures over 43degC. This can help to avoid causing thermal blisters in the scar tissue.

The cancer treatment in Wanfang Hospital is combined treatment(radiotherapy + chemotherapy + hyperthermia). But they combine those treatments in one day, patients may feel exhausted. At the same time, the departments need to communicate and catch the time point of treatment. Could you give us some advice how to arrange interval time for combined treatment? Or we could rearrange the treatment plan to one day radiotherapy + hyperthermia and another day chemotherapy + hyperthermia?

It is common to do only 1 or 2 hyperthermia treatments per week when used along with radiation therapy. This is because the boost to the radiation dose has been shown to extend for more than 24 hours after the heat treatment to enhance the radiation treatment of the next day. So if the hyperthermia was given only on a Tuesday and a Thursday, the radiation therapy treatments would be enhanced for Tuesday, Wednesday, Thursday, and Friday. The article 3185 shows a protocol where there was only one heat treatment per week. This would be better to be done on a day of radiation, but also before a day of another radiation treatment. Clinical evidence shows the early work showing an effect of hyperthermia 24 hours later to boost radiation therapy.