ESTRO 38 Abstract book

S862 ESTRO 38

parameters of the matched beams found to be fulfilling the recommendations. Results Between February 2017 and July 2018 we have treated two patients. The first case was a young male patient with Stage IV. MF with erythroderma, Sezary syndrome. The second case was a Stage III. male patient with mental retardation, this circumstance made the treatments even more difficult. Prescribed dose was: 30-36 Gy/1,8-2 Gy at D max . None of the patients have developed severe (grade III-IV) side effects during or following treatment. We perceived a grade II radio dermatitis in one of the cases, but treatment brake insertion was not necessary. Additional fields were used to complement the soles and perineal regions. Conclusion At 3 months follow-up both patients were in a remission regarding the skin symptoms, no late side effects were observed. The method we implemented in the clinic was suitable to manage and treat both patients with dementia and severe skin symptoms. EP-1599 Electronic brachytherapy for non-melanoma skin cancers: preliminary results of a pilot trial F. Maurizi 1 , G. Capezzali 1 , M. Mazza 1 , C. Blasi 1 , G.L. Moroni 1 , M. La Macchia 1 , A. Ciarmatori 2 , F. Palleri 2 , E. Argazzi 2 , S. Giancaterino 2 , M. Bono 2 , F. Bunkheila 1 1 A.O. Ospedali Riuniti Marche Nord, Radiotherapy, Pesaro, Italy ; 2 A.O. Ospedali Riuniti Marche Nord, Medical Physics, Pesaro, Italy Purpose or Objective Surface electronic brachytherapy (EBT) is an emerging alternative radiotherapy (RT) solution to external beam electron RT and high-dose-rate radionuclide-based brachytherapy for non-melanoma skin cancers. It can also be used as an alternative treatment to surgery for selected patients (pts). This prospective, single-center, non- randomized, pilot trial shows the clinical implementation of a new EBT system named Esteya® evaluating dosimetric features, the clinical safety and efficacy of this approach. Preliminary results are presented. Material and Methods Flatness and symmetry of X-Ray beams have been evaluated using a high definition 2D array equipped of liquid filled ionization chambers. Half Value Layer (HVL), PDD and absolute dose have been measured for each applicator with a soft x-ray parallel plate chamber and solid water. Dose distributions have been compared with the ones calculated for conventional electron treatments (Fig.1). Between November 2016 and August 2018, 47 lesions of 36 consecutive pts (mean age: 78 years, range: 55-96) with non-melanoma malignant skin cancer have been enrolled and analyzed. Fifteen pts presented primary squamous cell carcinomas (SCC) of eyelids and scalp and 12.8 % recurrent SCC of the scalp and nose, 10.6 % showed recurrent basal cell carcinomas (BCC) of the nose and forehead, 44.7 % BCC of nose and temporal area. Only lesions with a maximum diameter < 2,5 cm were treated with radiation dose of 40 Gy (5 Gy fraction, 2/week). Acute toxicity has been measured according to CTCAE (Common Terminology Criteria for Adverse Events) v4.03 scales and RTOG-EORTC scales were used to assess cosmetic results. Results All pts underwent clinical examination and photographs during RT, 4 weeks, 8 weeks, 3 months, and 6 months after treatment. Toxicity started after the 4 th fraction and worsened between the end and 4-6 weeks after RT. All pts presented erythema: moderate to brisk grade was scored in 66% cases (G2 CTCAE). Moist desquamation and crusting were shown by 6 pts, 2 patient presented moderate edema. Late toxicity was scored in 42.4 % pts: 10 pts showed slight pigmentation changes (G1 Late RTOG- EORTC) and 4 pts presented moderate telangiectasia (G2).

Results Median follow up from treatment was 5 years. Bleeding control was obtained in all symptomatic lesions (100%). Local control consisted of a partial regression or resolution of necrotic skin cavities in 70 % of the lesions . A durable ( over 2 years) complete resolution was obtained in 40% of the treated lesions . The 5–year cumulative incidence of local relapse and local progression were 15% and 30% respectively . At univariate analysis statistically significant prognostic factors for local relapse were diabetes, age over 80 years, diameter > 5 cm, necrosis , deep invasion with a tissue loss and site; the scalp was the most significant site for a good and durable local control (p< 0.03) ; fractionations and energies were not significant. At Pearson’s multivariate the diameter , necrosis and the site were confirmed the most significant poor prognostic factors. Conclusion Customized electron beam radiotherapy for head skin and scalp lesions is effective for palliation as bleeding or resolution with a good local control appearing an easy modality to treat monstrous and complicated lesions of very old population ameliorating quality of life. EP-1598 Efficient use of a modified Stanford TSEBT technique in the treatment of MF patients E. Csiki 1 , M. Simon 1,2 , J. Papp 1,2 , P. Árkosy 3 , Á. Kovács 1,2 1 University of Debrecen Med. and Health Science Centre- Clinic of Oncology, Department of Radiotherapy, Debrecen, Hungary ; 2 University of Pécs- Faculty of Health Sciences, Doctoral School of Health Sciences, Pécs, Hungary ; 3 University of Debrecen Med. and Health Science Centre- Clinic of Oncology, Department of Oncology, Debrecen, Hungary Purpose or Objective Mycosis fungoides (MF) has the highest incidence in cutaneous T-Cell lymphomas, although it is a very rare entity amongst lymphomas. TSEBT is one of the most effective skin directed therapy for MF and can be used after other type of therapies (PUVA, topical steroids, etc.). In early stage disease (IIB) the intent of therapy is curative, at later stages (stage IV) it is mostly palliative to mitigate skin symptoms. We have treated two patients with modified Stanford Total Skin Electron Body Radiotherapy (TSEBT) technique. As a result of their condition these patients are barely suitable to hold the treatment position during treatment. We have developed a method to easily move, treat and re-position the patients during radiotherapy to ensure the effective and safe treatments. Material and Methods During TSEBT entire skin homogeneous radiotherapy is carried out. Patients are irradiated with a nominal 6 MeV energy beam in High Dose Rate mode with a special applicator. In the treatment plane the beam energy decreased to 3.5 MeV, but it was sufficient to treat the skin surface and the underlying tissues. The beam size allowed by the special applicator in the plane of the isocenter was 40X40 cm. Patients were positioned in a special treatment frame, which had a rotating base plate, allowing the staff to easily re-position the patients between positions without removing them from the frame. An 8 mm thick Perspex had been attached to the frame to ensure the desired homogeneity of the electron beam in the treatment plane. The distance between the source and the Perspex was 360 cm, therefore a single beam was not sufficient. We matched two beams horizontally to perform the treatments. Geometrical matching was not plausible because of the extremely wide penumbra, a dosimetrical analysis was necessary to ensure the homogeneous border. The necessary angle to tilt the head was 18.5 °. Both dosimetrical and geometrical