Background
Systematic review and meta-analysis. 26 prospective studies (2 RCTs, 24 comparative cohorts), evaluating health-related quality of life (HRQOL) outcomes after proton therapy vs photon RT across tumor sites including prostate, HNC, CNS tumors, lung, and breast cancer. Aimed to determine whether dosimetric advantages of proton therapy translate into clinically meaningful HRQOL benefits. Verma V et al, JNCI 2018.
Interventions and follow up
Arm A: Proton therapy (passive scattering or pencil-beam scanning) across multiple tumor site
Arm B: Photon RT (IMRT, 3D-CRT) — same sites for compariso
Primary endpoint: HRQOL scores (disease-specific and generic instruments) at 6–24 month
mFollow up: 12–24 month
Arm B: Photon RT (IMRT, 3D-CRT) — same sites for compariso
Primary endpoint: HRQOL scores (disease-specific and generic instruments) at 6–24 month
mFollow up: 12–24 month
Results
Overall HRQOL benefit (proton): Statistically significant in HNC (swallowing, xerostomia), pediatric CNS (neurocognitive), and thoracic (pulmonary function) sites
Prostate HRQOL: No significant difference in bowel/urinary function vs IMRT
Breast/thoracic: Reduced pulmonary and cardiac HRQOL decline with proton
RCT-level evidence: Only 2 of 26 studies were RCTs
Prostate HRQOL: No significant difference in bowel/urinary function vs IMRT
Breast/thoracic: Reduced pulmonary and cardiac HRQOL decline with proton
RCT-level evidence: Only 2 of 26 studies were RCTs
Adverse events
Main adverse events: Proton: generally lower acute and late toxicity scores across sites. No unique proton-specific adverse effect on HRQOL identified. Proton brainstem/spinal cord dose advantages translate to reduced neuropathy scores in pediatric populations.
Conclusions
Proton therapy is associated with better HRQOL outcomes compared to photon RT in HNC, pediatric CNS, and thoracic malignancies. For prostate cancer, no HRQOL advantage was demonstrated over photon IMRT. The evidence base is predominantly observational and heterogeneous; randomized trial data are urgently needed across all sites.
Key Limitations
Key Limitations: Predominantly observational studies with selection bias. Only 2 RCTs with HRQOL outcomes included. Different instruments and follow-up times limit cross-study comparisons. Proton therapy centers serve a highly selected patient population with higher performance status. Industry funding in some included studies.
Clinical Context
This systematic review supports the HRQOL rationale for proton therapy in HNC and pediatric CNS tumors. For prostate cancer, IMRT and proton therapy have equivalent HRQOL — proton preference should be based on access and cost considerations. Insurance coverage for proton therapy in the US requires demonstrated clinical benefit, and ongoing trials (NRG-HN001, RTOG-0534) will provide higher-level evidence.
References