Laser Therapy for Cancer Treatment

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.

• 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 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.

How are lasers used during cancer surgery?

Laser surgery is a type of surgery that uses special light beams instead of instruments, such as scalpels, to perform surgical procedures. There are several different types of lasers, each with specific characteristics and each performing 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 reach. Several types of lasers are used for cancer treatment.

• Carbon dioxide (CO₂) lasers -  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 precancer cells.
• Neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers - 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 (LITT) -  LITT uses lasers to heat areas of the body 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 - Argon lasers pass only through superficial layers of tissue, such as skin. Photodynamic therapy (PDT) - PDT uses argon laser light to activate chemicals in the cancer cells.

What is photodynamic therapy?

Because it can selectively destroy cancer cells while sparing most healthy cells, photodynamic therapy (PDT) is useful for the treatment of certain cancer tumors. Photodynamic therapy targets chemicals, called photosensitizing agents, that react to argon light. These chemicals are not naturally found in cancer cells; they are injected into the patient. Cells throughout the body absorb the chemicals, which last longer in cancer cells than in healthy cells. At the right time, when the healthy cells surrounding the tumor are relatively free of the chemicals, the red light of an argon laser can be focused directly on the tumor. As the cancer cells absorb the light, a chemical reaction destroys them.

Argon lasers can pass through about an inch of tissue without damaging it, so PDT can be used to treat cancers that are close to the surface of the skin. It can also be directed at cancers that are located in the lining of the internal organs, such as:

• In the lungs, using a bronchoscope.
• In the esophagus and gastrointestinal tract, using an endoscope
• In the bladder, using a cystoscope

What cancers may be treated with laser therapy?

Lasers are used in surgery for some types of cancer because there is often 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:

• Vocal cord
• Cervical
• Skin
• Lung
• Vaginal
• Vulvar
• Penile

Laser surgery is also used for palliative surgery in cancer patients. Palliative surgery helps the patient feel better or function better even though it may not treat the cancer; for example, surgery to remove a growth that is making it difficult for a patient to eat comfortably.

What are the side effects of photodynamic therapy?

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 6 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 and all possible side effects of treatment before the treatment begins.