Photodynamic Therapy for Lung Cancer
For people with stage 0 lung cancers (small cancers that have not spread beyond the lining layer of cells in the lungs) photodynamic therapy, or PDT, may be an option to cure the cancer. For people whose lung cancers are at a more advanced stage, PDT can be used to improve the quality of life.
PDT offers hope
Most lung cancers start in the lining of the bronchi, the tubes that branch into the lungs from the windpipe, or bronchus. Routine screening tests don't exist for lung cancer as they do for cervical cancer (Pap smears) and colon cancer (fecal-occult blood tests). Thus, only a small number of lung cancers are detected in this early stage.
In carefully selected people whose tumors are small (less than 1 cm) and near the surface of the bronchi, PDT can provide 5-year survival rates comparable to those for radiation treatment or surgery.
Beyond the possible cure that PDT offers for the few people whose lung cancer is found early, it can also be used to control some of the symptoms of more advanced lung cancer. That can improve the quality of life for a person with cancer. Here are some examples:
PDT can help improve the quality of life for someone whose advanced tumor is so large that it interferes with breathing. The procedure can be used to reduce symptoms by shrinking the obstructive tumor. In these situations, PDT is as efficient as some other palliative methods, including electrosurgery, Nd-YAG laser, and brachytherapy.
Possible future improvements for PDT
PDT has many advantages. It can be done as an outpatient, has no long term side effects when used correctly, is less invasive than surgery, causes little scarring, can be targeted at only cancer cells, and can be repeated if needed. The main drawback of PDT is that the IV drugs remain in the person's skin for 4 to 6 weeks, which means that the person must stay totally out of the sun or risk getting a severe sunburn. It's use is also limited to areas that can be reached with light and cannot be used to treat large tumors. This may change if drugs of the future are stronger, then the laser beams may be able to penetrate more deeply. Another research direction is to develop new agents that are retained in the cancer cells longer, but clear from the skin cells faster.
Putting PDT to work
Though this treatment has been evolving for decades, it has been slow to catch on. Even so, many centers in the United States offer PDT, as do several scattered through Europe, Japan, and Canada.
People with lung cancer can locate a center by asking for a referral from their doctor. They can also find centers by searching the Internet, with assistance from a medical librarian.
Even with the better photosensitizing drugs that the future may hold--and laser beams that penetrate more deeply--for now, PDT is a procedure that can help only a small number of people diagnosed with lung cancer.