Innovative radiotherapy for uveal melanoma

Pulsed irradiation with proton beams

N Cassoux, R Dendale and P Verrelle

Background: Depending on its size uveal melanoma is treated by enucleation, brachytherapy (iodine disk) or by proton therapy (irradiation with a proton beam). This last technique is particularly interesting as it allows a homogenous irradiation of the tumor without affecting tissues around the tumor zone (point dose distribution in the Bragg peak) however it is associated with various side effects which are sometimes disabling.

The team recently demonstrated in mice that a high dose of irradiation in a very short time (ultra high-dose rate) in the form of electron pulses (flash irradiation) made it possible de destroy cancerous lesions while sparing adjacent health tissues (decrease of apoptosis and inflammatory reactions and absence of pulomary fibrosis).

Hypothesis: Developing a flash irradiation protocol would reduce side effects without altering the anti-tumor efficacy.

Objectives:

• Demonstrate the existence of a Flash effect in proton therapy
• Carry out a preclinical study of Flash irradiation in proton therapy in order to analyze potential side effects

Depending on the results, the technique will be studied in man in a clinical trial.