Lasers in Cancer Treatment

The word LASER actually stands for Light Amplification by Stimulated Emission of Radiation.

Laser light is different from regular light. The light from the sun or from a light bulb has many wavelengths and spreads out in all directions. Laser light, on the other hand, has a single wavelength and can be focused in a very narrow beam. This makes it both powerful and precise. Lasers can be used instead of blades (scalpels) for very careful surgical work, such as repairing a damaged retina in the eye or cutting through body tissue.

Types of lasers

Lasers are named for the liquid, gas, solid, or electronic substance that is used to create the light. Many types of lasers are used to treat medical problems, and new ones are being tested all the time. Today, 3 kinds of lasers are commonly used in cancer treatment. carbon dioxide (CO2), argon, and the neodymium: yttrium aluminum garnet (Nd:YAG).

Carbon dioxide (CO2)

The CO2 laser is mainly a surgical tool. It can cut or vaporize tissue with fairly little bleeding as the light energy changes to heat. This type of laser is used to remove thin layers from the surface of the skin without going into the deeper layers.

Argon

The argon laser only goes a short distance into tissue. It’s useful in treating skin problems and in eye surgery. It is sometimes used during colonoscopies (tests to look for colon cancer) to remove growths called polyps before they become cancer. It can be used with light-sensitive drugs to kill cancer cells in a treatment known as photodynamic therapy (PDT). (You can learn more about this in our document titled Photodynamic Therapy. Call us at 1-800-227-2345 for a copy, or read it on our Web site.)

Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG)

Light from this laser can go deeper into tissue than light from other types of lasers, and it can make blood clot quickly. Nd:YAG lasers can be used through thin flexible tubes called endoscopes to get to hard-to-reach parts inside the body, such as the swallowing tube (esophagus) or large intestine (colon). This light can also travel through optical fibers, which can be bent and placed into a tumor to heat it up and destroy it.

Other lasers used in medicine

Some newer types of lasers — the erbium: yttrium aluminum garnet (Er:YAG); holium: yttrium aluminum garnet (Ho:YAG), copper vapor, and diode lasers — are also being used in medical treatments.

Pros and cons of laser use in surgery

Lasers have some advantages (pros) and disadvantages (cons) compared with standard surgical tools.

Pros of laser surgery

• Lasers are more precise and exact than blades (scalpels). For instance, the tissue near a laser cut (incision) is not affected since there is little contact with skin or other tissue.
• The heat produced by lasers helps clean (sterilize) the edges of the body tissue that it’s cutting, reducing the risk of infection.
• Since laser heat seals blood vessels, there is less bleeding, swelling, pain, or scarring.
• Operating time may be shorter.
• Laser surgery may mean less cutting and damage to healthy tissues (it can be less invasive). For example, with fiber optics, laser light can be directed to parts of the body through very small cuts (incisions) without having to make a large incision.
• More procedures may be done in outpatient settings.
• Healing time is often shorter.

Cons of laser surgery

• Fewer doctors and nurses are trained to use lasers.
• Laser equipment costs a lot of money and is bulky compared with the usual surgical tools used. But advances in technology are slowly helping reduce their cost and size.
• Strict safety precautions must be followed in the operating room when lasers are used. For example, the entire surgical team and the patient must wear eye protection.
• The effects of some laser treatments may not last long, so they may need to be repeated. And sometimes the laser cannot remove all of the tumor in one treatment, so more treatments may be needed.

Treating cancer with lasers

Lasers were first used on skin tumors in 1961. Today one of the most common medical uses of lasers is in cancer treatment. They can be used in 2 ways to treat cancer:

• To shrink or destroy a tumor with heat
• To activate a chemical — known as a photosensitizing agent — that kills only the cancer cells. (This is called photodynamic therapy or PDT.)

Though lasers can be used alone, they are most often used along with other cancer treatments, such as chemotherapy or radiation.

Lasers are also being studied for treating or preventing side effects of common cancer treatments. For instance, some studies are looking at how lasers might be used to prevent or treat severe mouth sores caused by chemotherapy, and how they may be used to treat the swelling (lymphedema) that can result after breast surgery. More research is needed to learn about these possible uses for lasers.

Shrinking or destroying tumors directly

The CO2 and Nd:YAG lasers are used to shrink or destroy tumors. They can be used with thin, flexible tubes called endoscopes that let doctors see inside certain parts of the body, such as the bladder or stomach. The light from some lasers can be sent through an endoscope fitted with fiber optics. This lets doctors see and work in parts of the body that could not otherwise be reached except by major surgery. It also allows very precise aim of the laser beam.

Lasers can be used with low-power microscopes, too. This gives the doctor a larger view of the area being treated. When used with a an instrument that allows very fine movement (called a micromanipulator), laser systems can produce a cutting area as small as 200 microns in diameter — less than the width of a very fine thread.

Lasers are used to treat many kinds of cancer. In the intestines or large bowel, lasers are used to remove polyps, small growths that may become cancer. The CO2 laser can be used to treat pre-cancerous tissue and very early cancers of the cervix, vagina, and vulva.

Lasers are also used to remove tumors blocking the swallowing tube (esophagus) and large intestine (colon). This does not cure the cancer, but it relieves some symptoms, such as trouble swallowing.

The Nd:YAG laser has also been used to remove cancer that has spread to the lungs from other areas. This helps patients avoid surgery that would require removing large sections of lung. This type of laser cannot cure cancer, but it can improve breathing and other symptoms in many patients.

Cancers of the head, neck, airways, and lungs can be treated (but usually not cured) with lasers. Small tumors on the vocal cords may be treated with lasers instead of radiation in some patients. As with tumors blocking the esophagus, tumors blocking the upper airway can be partly removed to make breathing easier. Blockages deeper in the airway, such as in the branches of the breathing tubes (bronchi), can be treated with a flexible, lighted tube called a bronchoscope and an Nd:YAG laser.

Laser-induced interstitial thermotherapy (LITT) is based on the same idea as a cancer treatment called hyperthermia. Both methods use heat to help shrink tumors by damaging cells or depriving them of the things they need to live (like oxygen and food). In LITT, the laser light is passed through a fiber optic wire and right into a tumor, where it heats up, damaging or killing cancer cells. LITT is sometimes used to treat tumors in the liver.

Photodynamic therapy

In photodynamic therapy (PDT), a special drug called a photosensitizing agent is put into the bloodstream. Over time it is absorbed by body tissues. The drug stays in or around cancer cells for a longer time than it does in normal tissue. Shining a certain kind of light on the drug that is in the cancer cells causes a chemical reaction that then kills the cancer cells.

Photosensitizing agents are “turned on” or activated by a certain wavelength of light. For example, an argon laser can be used in PDT. When cancer cells that contain the photosensitizing agent are exposed to red light from this laser, it causes the chemical reaction that kills the cancer cells. Light exposure must be carefully timed so that it is used when most of the agent has left healthy cells, but is still in the cancer cells.

PDT can have some advantages over other treatments. Cancer cells can be singled out and destroyed but most normal cells are spared. The damaging effect of the photosensitizing agent happens only when the drug is exposed to light, and the side effects are fairly mild.

Still, PDT as it is currently used is not without its problems. Argon laser light cannot pass through more than about 1 centimeter of tissue (a little more than one-third of an inch), which means it’s not as useful against deeper tumors. And the photosensitizing agents used today can leave people very sensitive to light, causing sunburn-like reactions after only very brief sun exposure. This can greatly limit the patient’s activities until the body gets rid of the drug, which often takes weeks.

PDT is sometimes used to treat cancers and pre-cancers of the swallowing tube (esophagus), and certain kinds of lung cancer that can be reached with thin, flexible tubes called endoscopes. PDT is being studied for use in other cancers, such as those of the brain and prostate. Researchers also are looking at different kinds of lasers and new photosensitizer drugs that might work even better.

To learn more about PDT, see our document called Photodynamic Therapy.

The outlook for lasers in cancer treatment

Because of their power and precision, lasers are well-suited for certain cancer surgeries, and doctors are trying to find new and better ways to use them. As more cancer surgeons learn to use lasers, as the lasers themselves become smaller and cheaper, and as technology improves to allow tumors deep within the body to be treated, lasers will probably be used more often as part of cancer treatment.

To learn more

More from your American Cancer Society

We have selected some related information that may also be helpful to you. You can read these materials on our Web site, www.cancer.org, or order free copies from our toll-free number, 1-800-227-2345.

What Is Cancer? (also available in Spanish)

Surgery (also available in Spanish)

Endoscopy

Photodynamic Therapy

Hyperthermia

National organizations and Web sites*

Along with the American Cancer Society, other sources of information and support include:

National Cancer Institute
Toll-free number: 1-800-4-CANCER (1-800-422-6237)
Web site: www.cancer.gov

Provides accurate, up-to-date information on many cancer-related topics to patients, their families, and the general public

No matter who you are, we can help. Contact us anytime, day or night, for cancer-related information and support. Call us at 1-800-227-2345 or visit www.cancer.org.

References

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American Society for Laser Medicine & Surgery, Inc. Accessed at www.aslms.org on July 29, 2011.

Bjordal JM, Bensadoun RJ, Tunèr J, et al. A systematic review with meta-analysis of the effect of low-level laser therapy (LLLT) in cancer therapy-induced oral mucositis.Support Care Cancer. 2011;19(8):1069−1077.

Brown S, Brown EA, Walker I. The present and future role of photodynamic therapy in cancer treatment. Lancet Oncol. 2004;5:497−508.

Encyclopedia of Nursing and Allied Health. Laser Surgery. Accessed at www.enotes.com/nursing-encyclopedia/laser-surgery on July 28, 2011.

Fried NM. Therapeutic applications of lasers in urology: an update. Expert Rev Med Devices. 2006;3:81−94.

National Cancer Institute. Lasers in Cancer Treatment. Accessed at www.cancer.gov/cancertopics/factsheet/Therapy/lasers on July 29, 2011.

Rolle A, Pereszlenyi A, Koch R, et al. Is surgery for multiple lung metastases reasonable? A total of 328 consecutive patients with multiple-laser metastasectomies with a new 1318-nm Nd:YAG laser. J Thorac Cardiovasc Surg. 2006;131:1236−1242.

Vlastos G, Verkooijenb HM. Minimally invasive approaches for diagnosis and treatment of early-stage breast cancer. Oncologist. 2007;12:1−10.