Session code & type: PS02   - Poster Session
Session name: Poster Session - Clinics
Session date & time: 27-May-2016, 17:20 - 18:30

Pencil beam scanning proton therapy for lymphoma patients with mediastinal involvement: Prague´s single institution experience

K. Dedeckova 1, J. Stokucova 2, H. Mocikova 3, J. Markova 3, L. Gaherova 3, I. Kantorova 4, B. Ondrova 1, V. Vondracek 2, P. Vitek 1, J. Kubes 1
1PTC Prague, Proton Therapy Department, Prague, Czech Republic
2PTC Prague, Department of Clinical Physics, Prague, Czech Republic
3Faculty Hospital Kralovske Vinohrady and Third Faculty of Medicine, Internal Hematology Clinic, Prague, Czech Republic
4PTC Prague, Nuclear Medicine Department, Prague, Czech Republic

Radiotherapy (RT) is an important modality in the treatment of lymphomas. There is an effort to diminish risk of postRT toxicity via decreasing radiation load. Pencil beam scanning (PBS) proton RT is one of the methods to achieve this goal. To our knowledge, this is the first paper presenting PBS in deep inspiration breath hold (DIBH) for mediastinal lymphomas. Physical aspects of technique will be discussed in oral presentation at the PTCOG Conference. Methods:

Overall 43 patients (pts) were irradiated from 5/2013 to 1/2016. 35 pts were assessable for acute toxicity and early response (more than 3 months after RT). Characteristic of evaluable patients is displayed in Table 1.
Table 1.

Of evaluable pts 31 achieved CR, 2 pts local control with multiple sites progression, 1 pt partial remission (Deauville 4), 1 pt died from generalized CMV infection 5 months after RT (stp. allo-SCT before RT). Acute RT toxicity (RTOG scale) was mild, in most pts moderate dysphagia, radiodermatitis, transient xerostomia. 1 pt showed transient pneumonitis gr.II (44 CGE to mediastinum with bilateral hilar regions).  Asymptomatic changes in blood count occurred occasionally in patients after intensive systemic treatment.  Asymptomatic changes of lungs occurred on postRT CT scan in 2 pts. 

Proton RT using PBS in DIBH offers promising and safe possibility for most pts indicated for mediastinal RT. Early local control is comparable to standard photon techniques. Proton RT with its potential to decrease unintended healthy tissue irradiation should be consider in patients with necessity of mediastinal RT or reirradiation.