PTCOG Ocular Statement: Expert Summary of Current Practices and Future Developments in Ocular Proton Therapy

International Journal of Radiation Oncology*Biology*Physics, vol. 120, pp. 1307–1325

Abstract

Although rare cancers, ocular tumors are a threat to vision, quality of life, and potentially life expectancy of a patient. Ocular proton therapy (OPT) is a powerful tool for successfully treating this disease. The Particle Therapy Co-Operative Ocular Group) formulated an Evidence and Expert-Based Executive Summary of Current Practices and Future Developments in OPT: comparative dosimetric and clinical analysis with the different OPT systems is essential to set up planning guidelines, implement best practices, and establish benchmarks for eye preservation, vision, and quality of life measures. Contemporary prospective trials in select subsets of patients (eg, tumors near the optic disc and/or macula) may allow for dosimetric and clinical analysis between different radiation modalities and beamline systems to evaluate differences in radiation delivery and penumbra, and resultant tumor control, normal tissue complication rates, and overall clinical cost-effectiveness. To date, the combination of multimodal imaging (fundus photography, ultrasound, etc), ophthalmologist assessment, and clip surgery with radiation planning have been keys to successful treatment. Increased use of three-dimensional imaging (computed tomography/magnetic resonance imaging) is anticipated although its spatial resolution might be a limiting factor (eg, detection of flat diffuse tumor parts). Commercially produced ocular treatment-planning systems are under development and their future use is expected to expand across OPT centers. Future continuity of OPT will depend on the following: (1) maintaining and upgrading existing older dedicated low-energy facilities, (2) maintaining shared, degraded beamlines at large proton therapy centers, and (3) developing adapted gantry beams of sufficient quality to maintain the clinical benefits of sharp beam conformity. Option (1) potentially offers the sharpest beams, minimizing impact on healthy tissues, whereas (2) and (3) potentially offer the advantage of substantial long-term technical support and development as well as the introduction of new approaches. Significant patient throughputs and close cooperation between medical physics, ophthalmology, and radiation therapy, underpinned by mutual understanding, is crucial for a successful OPT service.

Authors 11

1. Jan Hrbáček corresponding

   Paul Scherrer Institute

   Affiliation as printed

   Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland. Electronic address: jan.hrbacek@psi.ch

   Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland

2. Andrzej Kacperek

   University College London

   Affiliation as printed

   University College London, London, United Kingdom

3. Jan-Willem M. Beenakker Aachen Department of Ophthalmology, Leiden University Medical Center Department of Radiation Oncology Department of Radiology, C.J. Gorter MRI Centre

   Leiden University Medical Center · Holland Particle Therapy Center

   Affiliation as printed

   Department of Ophthalmology, Leiden University Medical Center, Leiden, Netherlands; Department of Radiology, C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, Netherlands; Department of Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands; HollandPTC, Delft, Netherlands

   Department of Ophthalmology, Leiden University Medical Center, Leiden, Netherlands

   Department of Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands

   Department of Radiology, C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, Netherlands

   HollandPTC, Delft, Netherlands

4. Linda Mortimer

   Clatterbridge Cancer Centre NHS Foundation Trust

   Affiliation as printed

   Medical Physics Department, The Clatterbridge Cancer Centre NHS Foundation Trust, Birkenhead, United Kingdom

5. A. Denker

   Helmholtz-Zentrum Berlin für Materialien und Energie

   Affiliation as printed

   Helmholtz-Zentrum Berlin für Materialien und Energie, Proton Therapy (BE-APT), Berlin, Germany

6. A. Mazal

   IDCQ Hospitales y Sanidad, S.L.U.

   Affiliation as printed

   Medical Physics Service, Centro de Protonterapia Quironsalud, Madrid, Spain

7. Helen Alice Shih

   Harvard University · Massachusetts General Hospital

   Affiliation as printed

   Harvard Medical School, Boston, Massachusetts; Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts

   Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts

   Harvard Medical School, Boston, Massachusetts

8. R. Dendale

   Institut Curie

   Affiliation as printed

   Institut Curie Protontherapy Center, Orsay, France

9. Roelf L Slopsema
   Affiliation as printed

   Department of Radiation Oncology, Emory Proton Therapy Center, Atlanta, Georgia

10. Jens Heufelder

    Charité - Universitätsmedizin Berlin

    Affiliation as printed

    Department of Ophthalmology, Charité - Universitätsmedizin Berlin, BerlinProtonen am HZB, Berlin, Germany

    Department of Ophthalmology, Charité – Universitätsmedizin Berlin, BerlinProtonen am HZB, Berlin, Germany

11. Kavita Mishra

    University of California, San Francisco

    Affiliation as printed

    Proton Ocular Radiation Therapy Program, Department of Radiation Oncology, Osher Center for Integrative Health, Osher Foundation Endowed Chair in Clinical Programs in Integrative Health, University of California San Francisco, San Francisco, California