Proton therapy- the modality of choice for future radiation therapy management of Prostate Cancer?

BACKGROUND: Proton Therapy (PR) is an emerging treatment for prostate cancer (Pca) patients. However, limited and conflicting data exists regarding its ability to result in fewer bladder and rectal toxicities compared to Photon Therapy (PT), as well as its cost efficiency and plan robustness. MATERIALS AND METHODS: An electronic literature search was performed to acquire eligible studies published between 2007 and 2018. Studies comparing bladder and rectal dosimetry or Gastrointestinal (GI) and Genitourinary (GU) toxicities between PR and PT, the plan robustness of PR relative to motion and its cost efficiency for Pca patients were assessed. RESULTS: 28 studies were eligible for inclusion in this review. PR resulted in improved bladder and rectal dosimetry but did not manifest as improved GI/GU toxicities clinically compared to PT. PR plans were considered robust when specific corrections, techniques, positioning or immobilisation devices were applied. PR is not cost effective for intermediate risk Pca patients; however PR may be cost effective for younger or high risk Pca patients. CONCLUSION: PR offers improved bladder and rectal dosimetry compared to PT but this does not specifically translate to improved GI/GU toxicities clinically. The robustness of PR plans is acceptable under specific conditions. PR is not cost effective for all Pca patients.