Appeal type: Medical necessity
Decision: Upheld

Diagnosis: Prostate Cancer
Treatment: Proton beam therapy

Summary:
The patient is a gentleman with a recent diagnosis of Gleason 7, localized prostate cancer.  Definitive radiation therapy was recommended, and proton beam radiation therapy was requested.

Proton beam radiation therapy is a type of very precise external radiation treatment in which protons are used to treat cancer and other conditions.  Compared to photon, a proton beam that is delivered with sufficient energy has a low "entrance dose."  A proton beam also has a high-dose "Bragg peak" region, which is designed to cover the entire tumor and there is no "exit dose" beyond the tumor involved in proton radiation therapy.  Because of this unique property, proton beam therapy is highly successful in minimizing damage to normal tissue and surrounding organs, resulting in fewer side effects.  It is an FDA approved procedure and it is not subject to IRB (institutional review board) review.
	
There is emerging data showing that proton beam radiation therapy is safe and effective for the treatment of prostate cancer (1-9).  However, there is insufficient clinical peer-reviewed literature that showed that proton therapy is safer or more effective than the standard therapies, which include IMRT (intensity-modulated radiation therapy), prostate brachytherapy, surgery or combined modality.  In fact, several studies have concluded that additional studies are necessary with proton beam radiation therapy for the treatment of prostate cancer.  

In a 2007 study, Mayahara and associates evaluated 287 patients with prostate cancer treated with proton beam radiation therapy.  They concluded that "additional follow-up is warranted to elucidate the long-term safety and efficacy of proton therapy for prostate cancer."  Another 2005 study by Zietman et. al. investigated 393 patients with prostate cancer treated with a combination of photon and proton beam radiation therapy and concluded that "while the trial validates the use of proton-beam therapy, it did not test whether this modality is more or less efficacious than other more commonly available conformal techniques, brachytherapy or surgery."   

Another 2012 systematic review by Allen et al. concluded that there is evidence for the efficacy of proton beam therapy for treating prostate cancer but no suggestion that it is superior to photon based approaches.  A recent 2016 study from University of Florida evaluated 1,327 men with prostate cancer treated with proton therapy.  The five-year freedom from biochemical progression rates were 99%, 94%, and 74% in low-risk, intermediate-risk, and high-risk patients, respectively.  The authors concluded that "Image guided PT provided excellent biochemical control rates for patients with localized prostate cancer", but "Prospective clinical studies are needed to determine the comparative effectiveness of PT and other radiation treatment strategies."  

In addition, American Society for Radiation Oncology (ASTRO) states that "While proton beam therapy is not a new technology, its use in the treatment of prostate cancer is evolving.  ASTRO strongly supports allowing for coverage with evidence development for patients treated on clinical trials or within prospective registries."  However, it also concludes that "The comparative efficacy evidence of proton beam therapy is still being developed."   

NCCN guidelines also state that proton therapy is an option for prostate cancer, but no clear benefit over the existing therapy of intensity-modulated radiation therapy has been demonstrated.  IMRT with photon therapy is the standard of care for patients with prostate cancer that wish to undergo external beam radiation therapy.  Proton beam radiation therapy is not considered medically necessary due to availability of other available treatment modalities and non-superiority of proton beam radiation therapy compared to other standard options.