Oncology

How are lasers and energy-based devices used in oncology?

Lasers play a major role in the early detection and treatment of cancer as well as many other diseases. They can shrink or destroy tumors or precancerous growth. Lasers are most commonly used to treat superficial cancers—cancers of the surface of the body or the lining of internal organs—such as basal cell skin cancer and the very early stages of some cancers, such as cervical, penile, vaginal, vulvar, and non-small cell lung cancer. 

Lasers also may be used to relieve certain symptoms of cancer, such as bleeding or obstruction. For example, lasers can be used to shrink or destroy a tumor that is blocking a patient’s trachea or esophagus. Lasers also can be used to remove colon polypsor tumors that are blocking the colon or stomach.

Laser therapy can be used alone, but most often it is combined with other treatments, such as surgery, chemotherapy, or radiation therapy. In addition, lasers can seal nerve endings to reduce pain after surgery and seal lymph vessels to reduce swelling and limit the spread of tumor cells.

Three types of lasers are used to treat cancer:

• Carbon dioxide (CO₂ ) lasers
  
• Argon lasers
  
• Neodymium:yttrium-aluminum-garnet (Nd:YAG) lasers
  

Each of these can shrink or destroy tumors and can be used with endoscopes. CO₂ and argon lasers can cut the skin’s surface without going into deeper layers. Thus, they can be used to remove superficial cancers, such as skin cancer. In contrast, the Nd:YAG laser is more commonly applied through an endoscope to treat internal organs, such as the uterus, esophagus, and colon. Nd:YAG laser light can also travel through optical fibers into specific areas of the body during LITT. Argon lasers are often used to activate the drugs used in PDT.

Benefits of lasers and energy-based devices in oncology

• More precise than standard surgical tools (scalpels), which means less damage to normal tissues
  
• Reduced pain, bleeding, swelling and scarring
  
• Shorter operations—often done on an outpatient basis
  
• Less time for patients to heal after laser surgery
  
• Reduced risk of infection
  

Recent advances in lasers and energy-based devices in oncology
Infrared spectroscopy using IR lasers is a new development. Cancer and healthy tissue may have different transmissions in the IR range so it may be easier to determine benign marks and actual melanomas. With skin cancers, early detection is very important for patients’ survival rates.

Some porphyrins will accumulate in cancers and fluoresce if illuminated with a particular wavelength of light to show where the cancer is. If these same compounds are then illuminated with a different wavelength they become toxic and kill the cancer cells.

Laser-based systems are also starting to replace the use of x-rays. Using x-rays poses a challenge: high intensities are needed to be able to detect cancers well, but as the intensity of the x-ray is raised, so is the risk of the x-ray itself causing cancer. The alternative being studied is to use very fast laser pulses to image breasts as well as other parts of the body such as the brain.

Updated March 3, 2016