The term “laser” stands for “light amplification by the stimulated emission of radiation.” Laser light is concentrated so that it makes a very powerful and precise tool. Laser therapy uses light to treat cancer cells. Consider the following additional information regarding laser therapy.
- Lasers can cut a very tiny area, less than the width of the finest thread, to remove very small cancers without damaging surrounding tissue.
- Lasers are used to apply heat to tumors in order to shrink them.
- Lasers are sometimes used with drugs that are activated by laser light to kill cancer cells.
- Lasers can bend and go through tubes to access hard-to-reach places.
- Lasers are used in microscopes to enable physicians to view the site being treated.
Laser surgery is a type of surgery that uses special light beams instead of instruments, such as scapels, to perform surgical procedures. There are several different types of lasers, each with characteristics that perform specific functions during surgery. Laser light can be delivered either continuously or intermittently and can be used with fiber optics to treat areas of the body that are often difficult to access. The following lasers are some of the different types used for cancer treatment:
- Carbon dioxide (CO2) lasers – can remove a very thin layer of tissue from the surface of the skin without removing deeper layers. The CO2 laser may be used to remove skin cancers and some precancerous cells.
- Neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers – can penetrate deeper into tissue and can cause blood to clot quickly. The laser light can be carried through optical fibers to reach less accessible internal parts of the body. For example, the Nd:YAG laser can be used to treat throat cancer.
- Laser-induced interstitial thermotherapy – uses lasers to heat certain areas of the body. The lasers are directed to areas between organs (interstitial areas) that are near a tumor. The heat from the laser increases the temperature of the tumor, thereby shrinking, damaging or destroying the cancer cells.
- Argon lasers – pass only through superficial layers of tissue such as skin. Photodynamic therapy uses argon laser light to activate chemicals in the cancer cells.
Because cancer cells can be selectively destroyed while most healthy cells are spared, photodynamic therapy is useful for the treatment of certain cancer tumors. Photodynamic therapy uses chemicals in the cancer cells that react to the argon light. These chemicals, called photosensitizing agents, are not naturally found in the cancer cells. In PDT, the chemicals are given to the cancer patient by injection. Cells throughout the body absorb the chemicals. The chemicals collect and stay longer in the cancer cells than in the healthy cells. At the right time, when the healthy cells surrounding the tumor may already be relatively free of the chemicals, the red light of an argon laser can be focused directly on the tumor. It hits the tumor and, as the cells absorb the light, a chemical reaction destroys the cancer cells.
Argon lasers can pass through about an inch of tissue without damaging it, so PDT can be used for the treatment of cancers that are close to the surface of the skin. It also can be directed at cancers that are located in the lining of the internal organs:
- In the lungs by using a bronchoscope.
- In the esophagus and gastrointestinal tract by using an endoscope.
- In the bladder by using a cystoscope.
Lasers are used in surgery for the following types of cancer because they often have a special requirement that only lasers can meet — such as the ability to reach a hard to treat location, apply heat or cut only a very small area:
- Palliative surgery
- Vocal cord
Laser surgery also is used for palliative surgery in cancer patients. The purpose of palliative surgery is to help the patient feel better or function better even though it may not treat the cancer. An example of this type of surgery may involve surgery to remove a growth that is making it difficult for a patient to eat comfortably.
The side effects of photodynamic therapy are relatively mild and may include a small amount of damage to healthy tissue. Also, a patient’s skin and eyes are sensitive to light for as long as six weeks or more after treatment is completed. Depending on the area that is treated, patients may experience other temporary side effects. As each person’s individual medical profile and diagnosis is different, so is his or her reaction to treatment. Side effects may be severe, mild or absent. Be sure to discuss with your cancer care team any/all possible side effects of treatment before the treatment begins.