MSM (MethylSulfonylMethane) is an abbreviation of methylsulfonylmethane, an organic form of sulfur. The chemical formula of MSM is CH3SO2CH3. It is the form in which sulfur is biologically active and appears in nature in all living organisms.
Radiation Therapy for Non-Small Cell Lung Cancer
Radiation therapy uses high-energy rays (such as x-rays) or particles to kill cancer cells.
When might radiation therapy be used?
Depending on the stage of the non-small cell lung cancer (NSCLC) and other factors, radiation therapy might be used:
Types of radiation therapy
There are 2 main types of radiation therapy:
External beam radiation therapy
External beam radiation therapy (EBRT) focuses radiation from outside the body on the cancer. This is the type of radiation therapy most often used to treat NSCLC or its spread to other organs.
Before your treatments start, the radiation team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. This planning session, called simulation, usually includes getting imaging tests such as CT scans.
Treatment is much like getting an x-ray, but the radiation dose is stronger. The procedure itself is painless. Each treatment lasts only a few minutes, although the setup time – getting you into place for treatment – usually takes longer. Most often, radiation treatments to the lungs are given 5 days a week for 5 to 7 weeks, but this can vary based on the type of EBRT and the reason it’s being given.
In recent years, newer EBRT techniques have been shown to help doctors treat lung cancers more accurately while lowering the radiation exposure to nearby healthy tissues. These include:
Three-dimensional conformal radiation therapy (3D-CRT): 3D-CRT uses special computers to precisely map the tumor’s location. Radiation beams are then shaped and aimed at the tumor(s) from several directions, which makes it less likely to damage normal tissues.
Intensity modulated radiation therapy (IMRT): IMRT is an advanced form of 3D therapy. It uses a computer-driven machine that moves around you as it delivers radiation. Along with shaping the beams and aiming them at the tumor from several angles, the intensity (strength) of the beams can be adjusted to limit the dose reaching nearby normal tissues. This technique is used most often if tumors are near important structures such as the spinal cord. Many cancer centers now use IMRT.
A variation of IMRT is called volumetric modulated arc therapy (VMAT). It uses a machine that delivers radiation quickly as it rotates once around the body. This allows each treatment to be given over just a few minutes.
Stereotactic body radiation therapy (SBRT): SBRT, also known as stereotactic ablative radiotherapy (SABR), is sometimes used to treat very early-stage lung cancers when surgery isn’t an option due to a person’s health or in people who don’t want surgery.
Instead of giving a small dose of radiation each day for several weeks, SBRT uses very focused beams of high-dose radiation given in fewer (usually 1 to 5) treatments. Several beams are aimed at the tumor from different angles. To target the radiation precisely, you are put in a specially designed body frame for each treatment. This reduces the movement of the lung tumor during breathing. Like other forms of external radiation, the treatment itself is painless.
Early results with SBRT for smaller lung tumors have been very promising, and it seems to have a low risk of complications. It is also being studied for tumors that have spread to other parts of the body, such as the bones or liver.
Stereotactic radiosurgery (SRS): SRS is a type of stereotactic radiation therapy that is given in only one session. It can sometimes be used instead of or along with surgery for single tumors that have spread to the brain. In one version of this treatment, a machine called a Gamma Knife® focuses about 200 beams of radiation on the tumor from different angles over a few minutes to hours. Your head is kept in the same position with a rigid frame. In another version, a linear accelerator (a machine that creates radiation) that is controlled by a computer moves around your head to deliver radiation to the tumor from many different angles. These treatments can be repeated if needed.
Brachytherapy (internal radiation therapy)
In people with NSCLC, brachytherapy is sometimes used to shrink tumors in the airway to relieve symptoms.
For this type of treatment, the doctor places a small source of radioactive material (often in the form of small pellets) directly into the cancer or into the airway next to the cancer. This is usually done through a bronchoscope, but it may also be done during surgery. The radiation travels only a short distance from the source, limiting the effects on surrounding healthy tissues. The radiation source is usually removed after a short time. Less often, small radioactive “seeds” are left in place permanently, and the radiation gets weaker over several weeks.
Possible side effects of radiation therapy
If you are going to get radiation therapy, it’s important to ask your doctor beforehand about the possible side effects so you know what to expect. Common side effects depend on where the radiation is aimed and can include:
Often these go away after treatment. When radiation is given with chemotherapy, the side effects are often worse.
Radiation therapy to the chest may damage your lungs and cause a cough, problems breathing, and shortness of breath. These usually improve after treatment is over, although sometimes they may not go away completely.
Your esophagus, which is in the middle of your chest, may be exposed to radiation, which could cause a sore throat and trouble swallowing during treatment. This might make it hard to eat anything other than soft foods or liquids for a while. This also improves after completion of treatment.
Radiation therapy to large areas of the brain can sometimes cause memory loss, headaches, trouble thinking, or reduced sexual desire. Usually these symptoms are minor compared with those caused by a brain tumor, but they can affect your quality of life.