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.
