Laser Therapy (Photocoagulation or Thermotherapy) for Retinoblastoma

Lasers are highly focused beams of light that can be used to heat and destroy body tissues. Different types of laser therapy can sometimes be used to treat small retinoblastoma tumors.

Laser photocoagulation

Photocoagulation is a type of treatment that uses a laser beam aimed through the pupil (the dark spot in the front of the eye). The laser is focused on the blood vessels that surround and supply the tumor, destroying them with heat. Without a good blood supply, cancer cells will die. Photocoagulation is only effective for smaller tumors toward the back of the eye.

Your child will be asleep (under general anesthesia) during the treatment. The treatment is usually given 2 or 3 times, with about a month between treatments. If chemotherapy is needed, laser therapy is usually given after, since the chemotherapy reaches the tumor cells through the blood vessels. Giving chemotherapy after laser treatments may be less effective.

Possible side effects

In some cases, laser therapy can damage the retina, which can lead to blind spots or temporarily cause the retina to detach from the back of the eyeball.

Thermotherapy

For thermotherapy, also called transpupillary thermal therapy (TTT), the doctor uses a type of laser that applies infrared light directly to the tumor to heat and kill the tumor cells. The temperatures are not quite as high as those used in photocoagulation, so some of the blood vessels on the retina may be spared.

Thermotherapy can be used alone for very small tumors. For larger tumors, it can be used along with chemotherapy (called thermochemotherapy) or with radiation therapy (called thermoradiotherapy). Heat seems to help these other treatments work better.

The treatment is given while the child is asleep (under general anesthesia), usually for about 10 minutes at a time. Typically, 3 treatments about a month apart are needed to control each tumor. When used as part of thermochemotherapy, the heat is usually applied at a lower temperature over a slightly longer period, starting within a few hours after chemotherapy.

Possible side effects

Thermotherapy can sometimes cause part of the iris (the colored part of the eye) to shrink. Other possible effects include clouding of part of the eye lens or damage to the retina, which might affect vision.