Several different lasers are used to destroy retinoblastoma tumours in the eye with heat.
When Laser Is Used
Laser is used to treat small tumours in the back of the eye.
Sometimes laser is used together with chemotherapy to treat slightly larger tumours, or those close to the optic nerve or centre of vision.
Laser is given after chemotherapy. Using laser before chemotherapy will reduce the flow of chemotherapy into the cancer cells as laser cuts off blood supply. Chemotherapy reduces tumour size so it can be destroyed with laser. This is called consolidation.
How Laser Is Given
The child receives a general anaesthetic.
Focused beams of light are delivered through an ophthalmoscope.
The laser beam is first applied around the tumour’s margin to destroy its blood supply. Subsequent laser burns may be applied directly to the tumour. Repeated treatments are usually necessary to kill the tumours completely.
Laser only causes scarring in the precise spot that the laser is applied, so it it more desirable than cryotherapy for tumours near the central vision. Small tumours can be lasered repeatedly, reducing the need for more aggressive treatments.
Some tumours are resistant to laser. Too much laser can cause scarring and dragging of surrounding retina.
Thermotherapy uses laser as a heat source to sensitize small tumours to chemotherapy.
The child receives an infusion of chemotherapy immediately before being taken to the operating room Under general anaesthetic, a diode laser is applied to the tumour surface. Heating the tumour increases absorption of chemotherapy.
Thermotherapy has not been shown to be as effective as chemotherapy with consolidation laser and/or cryotherapy, when the tumour is directly destroyed by laser.
Laser causes minimal side effects. Multiple treatments to tumours in the central vision may damage the retina over time. Excessive laser energy can cause bleeding and vitreous seeding. Lasering through a poorly dilated pupil can cause iris burns, pupil deformities or cataract.
Questions To Ask the Doctors
- Where are my child’s tumours located that you plan to laser?
- How big are these tumours?
- Will my child need more than one laser treatment?
- How often will you laser the tumour/s?
- Will my child need chemotherapy with the laser?
- How will you combine the chemotherapy and laser?
- How might this laser treatment impact my child’s vision?