Radiation Therapy (or “radiotherapy”) involves the localized use of high–dose radiation on pleural mesothelioma cancer cells. It works by destroying the cancer cells in the affected area.
The treatment is divided into several sessions, usually one session a day for five days with a break at the weekend. This ensures that less damage is done to healthy cells than to cancer cells. The damage to healthy cells is usually temporary, but is the reason that radiotherapy has some unwanted side effects such as fatigue and skin changes.
Radiation therapy can both reduce the size of a tumor and relieve symptoms like pain and shortness of breath. It is frequently used after surgery in order to kill the cancer cells which remain after the tumor is removed. It can also be combined with chemotherapy to combat the metastatic spread of the disease. However, doctors will limit its use depending on the volume of the tumor and how close it is to other vital organs.
Intensity Modulated Radiation
In intensity modulated radiation therapy(IMRT), very small beams, or beamlets, are aimed at a tumor from many angles. IMRT permits the delivery of a high dose of radiation to the cancer while minimizing dose to other sensitive organs. Here multiple beams are all focused on the prostate. Each of these beams has a number of sub-beams or segments, and the intensity of each segment is varied according to the treatment plan.
During treatment, the radiation intensity of each beamlet is controlled, and the beam shape changes hundreds of times during each treatment. As a result, the radiation dose bends around important healthy tissues in a way that is impossible with other techniques. Because of the complexity of these motions, physicians use special high-speed computers, treatment-planning software, diagnostic imaging and patient-positioning devices to plan treatments and control the radiation dose during therapy.
For IMRT to be effective, the anatomical position of the tumor and surrounding healthy tissues must be accurately defined. Computed tomography (CT), positron emission tomography (PET) and magnetic resonance (MR) imaging provide the necessary three-dimensional anatomical information. It’s also important to accurately position and immobilize the patient during treatment. This may be done with special head frames (if the head or brain is being treated), or with advanced imaging devices such as electronic portal imaging and scanning ultrasound, which provide daily information about the location of internal organs. Some organs, such as the prostate, move due to normal daily volume changes in the bladder and rectum. Gold seeds may be placed into the prostate to track prostate movement daily and ensure more precise targeting.
A device called a multileaf collimator adjusts the size and shape of the computer-determined radiation beams. The collimator, a computer-controlled mechanical device, consists of up to 120 individually adjusted metal leaves. These leaves move across the irradiated tissue while the beam is on, blocking out some areas and filtering others to vary the beam intensity and precisely distribute the radiation dosage.
Radiation oncologists usually administer a regimen of IMRT treatments over four to eight weeks. The total dose of radiation and the number of treatments given depend on the size, location and type of cancer; the patient’s general health; and other medical therapy the patient is receiving.
Radiofrequency Catheter Ablation
Ablation is a medical term that refers to any procedure performed to destroy diseased or damaged tissue in the body. Radiofrequency Catheter Ablation is a technique in which a thin tube, or catheter, is inserted through the skin or threaded through the blood vessels to the site of disease. Extreme heat or cold, alcohol, chemotherapy drugs or other therapies are delivered through the catheter to the diseased tissue.
RFA treats disease with heat, a technique preferred by many cancer experts because it can reliably destroy a small, targeted area of tissue without healthy affecting structures beyond the treatment site. With RFA, the doctor can pinpoint target areas with accuracy and monitor and control the temperature of heat therapy.
Note: Catheter ablation also can be performed by surgeons as a surgical procedure called intra-operative catheter ablation. There are a number of differences between surgery and interventional radiology (IR). IR treatment tools are usually inserted through a small nick in the skin. There are no surgical incisions, no stitches and no scars. General anesthesia is not needed for many IR procedures, and in most cases they are less painful and have fewer risks and complications than surgery. Most conditions treated with IR can be done in an outpatient setting, or require hospitalization for only a brief time. Patients treated with IR can expect shorter hospital stays – and faster recoveries – than surgical patients. Many people resume normal activities within a few days after RFA or other IR procedures.