ESTRO 36 Abstract Book

S977 ESTRO 36 2017 _______________________________________________________________________________________________

EP-1806 HDR brachytherapy for superficial non- melanoma skin cancers. C. De la Pinta 1 , T. Muñoz 1 , J. Dominguez 1 , A. Montero 2 1 Hospital Ramon y Cajal, Radiation Oncology, Madrid, Spain 2 Radiation Oncology, Madrid, Spain Purpose or Objective The aim of this study was to evaluate the clinical and cosmetic outcomes in patients treated with high-dose-rate brachytherapy for non-melanoma skin cancer and disease- specific and overall survival. Material and Methods All patients referred for interstitial brachytherapy in our centre from 2007 to 2016 with non-melanoma skin cancer without distant metastases were retrospectively analysed (n=13). Median age was 7 years (range 54-88). Treatment consisted of brachytherapy alone (10p) or after surgery (3p). Patients with histologically confirmed squamous carcinoma (4p), and basal cell carcinoma (9p). All lesions were macroscopic. Lesions were located on the head and neck: nasal skin (5p), periocular skin (4p) and ear skin (4p). All patients were treated with interstitial brachytherapy median implant dose 53 Gy (range 45- 66Gy). Inclusion criteria were as follows: head and neck location and malignant tumors. Results From January 2007, 13 patients were treated. Median follow-up was 36 months (range 6-68 months), local control was achieved on clinical examination. Acute toxicities (8/13p) consisted of ephitelitis grade 1 (2p) and grade 2 (6p). Cosmesis was good or excellent in 12p. Late skin hypopigmentation were observed in 7 patients. Not acute toxicities grades 3 or 4 were reported. Grade 4 complication rate for all patients was 7,6% (one patient presented skin necrosis) Among 13 patients studied, 4 lost follow-up and they were excluded from the survival analysis. Preservation of organ functions were in all patients. Using Kaplan-Meier analysis overall survival after minimum follow-up of 36 months was 93% and disease-free survival was 75%. One patient had a locoregional recurrence. Conclusion Interstitial brachytherapy is a good choice to deliver high- dose radiation in tumor after surgery or as an exclusive treatment in non-melanoma skin cancers. This treatment offers adequate locoregional control with acceptable range of complications. EP-1765 Volume delineation based on 18FDG-PET and MRI in head and neck cancer treated with IG-VMAT L. Méndez Blanco 1 , C. Herrero 2 , M. Fueyo 1 , A. Martos 1 , D. Abad 2 , P. Santin 1 , S. Palizas 1 , D. Alonso 1 , A. Rios 1 , M. Vilches 2 , R. Cabanillas 1 1 Institute of Molecular and Oncological Medicine of Asturias, Radiation Oncology, Oviedo, Spain 2 Institute of Molecular and Oncological Medicine of Asturias, Medical Physics, Oviedo, Spain Purpose or Objective Image Guided-Volumetric Modulated Arc Therapy (IG- VMAT) is being increasingly used to treat locally advanced head and neck cancers. In this context 18-FDG-PET and MRI are becoming especially useful for accurate target volume delineation. Material and Methods Between November 2012 and October 2015, 38 patients with head and neck carcinomas were treated at our institution with IG-VMAT. Sites included were the nasopharynx (14), oropharynx (5), hypopharynx (4), larynx (6), paranasal sinuses and nasal cavity (3), thyroid (1), parotid (1) and metastatic neck nodes from an unknown primary (4). Each patient underwent endoscopy, contrast enhanced CT, MRI and 18-FDG PET scans. Plans were

acute tolerance and can predict the absence or minimal risk of late toxicity to treatment. Conclusion This clinical case and the previously reported studies of LRAB revealing similar rates of tumor control and survival to radical cystectomy constitute a hope in terms of quality of life for the most minimally invasive conservative treatment in a selected group of patients with localized MIBC. EP-1805 Interstitial and superficial brachytherapy for skin cancer S. Brovchuk 1 , S. Romanenko 1 , N. Ratushnia 1 , O. Vaskevych 1 1 Kyiv Regional Oncology Dispensary, Radiotherapy department, Kyiv, Ukraine Purpose or Objective The main purpose of this work was to demonstrate the capabilities of brachytherapy in skin cancer treatment. Malignant skin lesions are highly frequent type of cancer. Between two main non-melanoma forms, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), BCC accounts for about 70%, and SCC of about 30%. And while, in our practice, for treatment of SCC in some cases external beam radiotherapy (EBRT) was required to irradiate regional lymph nodes, BCC, which is almost always local, is perfectly suitable for monobrachytherapy treatment. Material and Methods In 70% of cases (in our practice more than that) skin tumors are located on head and neck, where high conformity is extremely important. If invasion of a tumor was less than 5 mm deep, accommodated to the surface mold applications were used, if invasion of a tumor 5 mm or more, interstitial implants were used (the examples are presented on Image 1). Radiation dose was delivered using high dose rate (HDR) afterloader with Ir192 radioactive source and was prescribed in case of BCC at 0.5 cm from visible lesion (growth tumor volume GTV), the enclosed volume corresponds to clinical tumor volume (CTV), in case of SCC at 1-1.5 cm from GTV the enclosed volume corresponds to CTV (planning tumor volume PTV=CTV). Dose fractionation (every day treatment, 5 days per week): for BCC cases - dose per fraction (fr) 4Gy in 2 cases and the total dose (TD) of 48Gy (12fr), 5.2Gy per fraction in 39 cases and TD=41.6Gy (8fr), 6Gy per fraction in 5 cases and TD=42Gy(7fr); for SCC cases - dose per fraction 5.2Gy in 5 cases and TD=46.8Gy (9fr), dose per fraction in 6.3Gy 2 cases and TD=44.1Gy(7fr). Equivalent dose to standard fractionation was about 58- 60 Gy (a/b ratio was taken 6-7Gy (BCC) and 10Gy (SCC)). Treatment planning was performed on CT images, the ratio of CTV that received 150% of the prescribed dose (CTV 150 ) to CTV 100 was kept below 0.45 (CTV 150 / CTV 100 - <0.45), that constrain in interstitial technique, where radiation source is inside the tissue, is achieved when spacing between implants is about 1-1.2 cm. Results Totally 53 patients (46 – BCC cases, 7 – CSS cases) were treated acording to the described method during clinical work in 2013 (clinical example is presented on Image 2); median follow-up 2.5 years (range from 2 to 3 years); 4 patients had local recurance and one lymph node failure (3-BCC cases and 2 (1 local+1 lymph node) – CSS cases). Conclusion Brachytherapy method of delivering radiation dose is naturally the most conformal, which also is challenging, but using interstitial implants or, accommodated to the skin surface, mold applications, gives good results. Dose per fraction of 6Gy and more lead to higher late complications (fibrosis in our experience).