The American Society for Radiation Oncology (ASTRO) has issued a new Model Policy for proton beam therapy (PBT) that details which cancer diagnoses meets ASTRO's evidence-based standards and should be covered by private insurers and Medicare. Developed by leading radiation oncologists and medical physicists, including significant input from expert representatives in proton therapy, this Model Policy supports PBT coverage for appropriate patients and identifies areas where coverage with evidence development and further research are needed.PBT's reduced radiation dose to healthy tissues is attractive because it can reduce side effects for patients, which potentially increases their quality of life. To date, scientific evidence exists confirming that PBT is particularly useful in a number of pediatric cancers, particularly those in the brain, as well as for certain adult cancers such as ocular melanoma.
In identifying and describing appropriate use of proton-beam therapy, the policy lists four circumstances when use of the technology is reasonable (and most pediatric cases would then qualify):
1. Target volume is close to a critical structure, requiring a steep dose gradient outside the target to limit the structure's exposure.
2. A decrease in dose inhomogeneity in a large treatment volume is required to avoid an excessive "hotspot" within the target volume.
3. Use of photon-based therapy carries an increased risk of clinically meaningful normal-tissue toxicity.
4. The same area or an adjacent area has been previously irradiated, increasing the need for sculpting to limit the cumulative radiation dose.