Radiotherapy Articles

Factors Influencing the Outcome of Radiotherapy in Malignant Mesothelioma of the Pleura - A Single-Institution Experience with 189 Patients.

Int J Radiat Oncol Biol Phys 1999 Feb 1;43(3):511-6
de Graaf-Strukowska L, van der Zee J, van Putten W, Senan S
Department of Radiation Oncology, Daniel den Hoed Cancer Center/University Hospital Rotterdam, The Netherlands.

PURPOSE: To determine the factors influencing the response to palliative radiotherapy 9RT) in malignant mesothelioma of the pleura (MM).

METHODS AND MATERIALS: A retrospective review was conducted of the records of all patients with mesothelioma who were referred to our institution between 1979 and 1996. A total of 227 RT series were administered to 189 patients with MM. Of these, 21 patients with chest wall nodules also received concomitant local hyperthermia.

RESULTS: The median survival was 5 months from the start of RT and only 17% of patients were alive at 1 year after treatment. Chest pain and painful chest wall metastases were the main indications for RT. A higher local response rate was seen for patients treated with a 4-Gy per fraction scheme, vs. those receiving fractions of less than 4 Gy (50% vs. 39%). Pain recurrence occurred predominantly within the previous RT field, and pain recurred after a median of 69 days (range 32-363) in the group treated using 4-Gy fractions. When compared with a matched group, patients treated with combined RT and hyperthermia had higher response rates and fewer in-field recurrences.

CONCLUSIONS: RT provides local palliation in at least 50% of patients with MM who were treated using a 4-Gy/fraction scheme to a media dose of 36 Gy. The low response rates with RT alone suggest that combined RT and local hyperthermia should be further evaluated in MM.

PMID: 10078630, UI: 99176516

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What's New in Radiation Therapy?

Stereotactic surgery or stereotactic radiation therapy delivers a large precise radiation dose to a small tumor area. The term surgery may be confusing since no incision is actually made. The most common site being treated with this technique is the brain but researchers are looking for ways to use this technique with other types of cancer. The linear accelerator or a machine called a Gamma Knife is used to deliver this treatment.

Three-dimensional conformal radiation therapy (3DCRT) uses special computers to very precisely map the location of the cancer. The patient is fitted with a plastic mold or cast to keep the body part still the radiation can be aimed more accurately from several directions. Because the procedure is new, its impact on long-term survival is not yet known. Early research suggests that by aiming the radiation more accurately, it is possible to reduce radiation damage to normal tissues and better fight the cancer by increasing the radiation dose to the cancer. These results have generated an enthusiasm in further developing this mode of radiotherapy.

A related technique, conformal proton beam radiation therapy, uses proton beams instead of x-rays. Protons are parts of atoms that cause little damage to tissues they pass through but are very effective in killing cells at the end of their path. This means that proton beam radiation may be able to deliver more radiation to the cancer while reducing side effects on nearby normal tissues.

Intraoperative radiation therapy (IORT) delivers radiation at the time of surgery directly to the area of cancer. It is more often used in abdominal or pelvic cancers and in cancers that have a tendency to return. IORT reduces the amount of tissue that is exposed to radiation because normal tissues can be moved out of the way during surgery and protected, allowing a higher dose of radiation to the cancer. Often hospitals deliver the radiation in the radiation therapy department, however, some hospitals have mobile machines that can be moved from room to room to deliver the IORT.

Hyperthermia refers to the use of heat. Heat has been found to kill cancer cells but when used alone, it does not destroy enough cells to cure the cancer. Heat created by microwaves and ultrasound has been studied in combination with radiation and appears to improve the effect of the radiation.

Chemical modifiers or radiosensitizers are substances that make cancer more sensitive to radiation. Researchers are trying to find substances that will either make the tumor more sensitive to radiation without affecting normal tissues or that will protect normal cells from radiation.

Boron neutron capture therapy is an experimental type of radiation therapy that is sometimes used in brain tumors. A compound containing boron is given into the patient's blood and concentrates in the brain tumor. The brain is then treated with neutrons from a nuclear reactor. When a neutron hits a boron atom, a type of radiation is released that has high energy that does not extend far into the surrounding normal brain tissue. The value of this treatment is not yet known.

Source: American Cancer Society