ESTRO 2023 - Abstract Book

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ESTRO 2023

metastases in 2, local recurrence in one, and local plus regional recurrence in one. The 1- and 2-year OS rates were 84.4% (95% CI 68.4%-92.7%) and 53.4% (95% CI 25.3%-75.0%), respectively. The median PFS and OS were 16.4 and 28.4 months. The 2-year OS rates of CIRT with and without ICIs were 88.2% (95% CI 67.5%-96.1%) and 24.1% (95% CI 4.0%-53.2%), respectively. Mucositis during/at the end of treatment was G1 and G2 for 16 pts (39%) and 25 pts (61%), respectively. No G2 or higher acute mucositis and dermatitis within 3 months was observed. G3 or higher late toxicities were observed in 2 patients (5%). One patient developed ipsilateral blindness (G4), and one developed G3 visual impairment. Conclusion Our preliminary data of CIRT has shown acceptable toxicities and excellent local control for MMHN. However, a larger series of patients and a longer follow-up are needed to better investigate outcomes.

PO-1201 Prognostic impact of second primary cancers in laryngeal cancer patients treated with radiotherapy

C. Makita 1 , T. Mori 1 , H. Takano 1 , T. Kumano 1 , M. Matsuo 1

1 Gifu University, Radiology, Gifu, Japan

Purpose or Objective Second primary cancers (SPCs) develop in 3.8-20.5% of patients with laryngeal cancer. The aim of this study is to investigate the impact of SPCs in patient treated with radiotherapy for laryngeal cancer. Materials and Methods We retrospective reviewed laryngeal cancer patients who underwent radical radiotherapy from January 2007 to December 2018. Median age was 70 years old (range, 40-88), male/female=107/4, supraglottic/glottic/subglottic=8/101/2, T: 1a/1b/2/3=45/14/44/8, N: 0/1/2b/2c=101/8/1/1, 47 patients (41.8%) were treated with concurrent chemotherapy. Fifty eight patients were treated with conventional 66-70 Gy (daily 2 Gy/fraction), and 53 patients were treated with hypofractionated 56.25-67.5 Gy (daily 2.25 Gy/fraction). According to the timing of diagnosis for each constituent tumor, SPCs are classified into 2 categories: synchronous SPCs if constituent tumors emerge simultaneously or within 2 months or metachronous SPCs otherwise. Results The median follow-up period was 66 months (5-122 months), the 5-year survival rate was 82.3%, the progression-free survival rate was 84.8%, the local control rate was 81.8%, and the larynx preservation rate was 91.9%. Recurrence was seen in 18 cases, and the recurrence type was local in 16 cases and cervical lymph node in 2 cases. Death from the primary disease occurred in 4 cases, while death from other diseases was observed in 20 cases (SPC in 12 cases, pneumonia in 3 cases, ALS in 1 case, accidental death in 1 case, heart failure in 1 case, and unknown in 2 cases). Synchronous SPCs were observed in 22 cases (20%), and the cumulative incidence of metachronous SPCs was 22.5% at 5 years. On multivariate analysis, age, PS, T-stage, and presence of synchronous and metachronous SPCs were significant prognostic factors for overall survival (HR, 0.28; 95% CI, 0.11-0.95; P=.05). Gastric cancer (11 cases) was the most common SPC, followed by lung cancer (9 cases) and esophageal cancer (5 cases). Conclusion SPCs were considered to be an important prognostic factor. Future attempts to improve laryngeal cancer survival need to target SPCs. S. Ramos 1 , S. Simões 2 , O. Carvalhosa 2 , M. Amorim 2 , C. Silva 3 , A. Costa 4 , G. Campos 4 , G. Fonseca 4 , M. Carvalho 4 , P. Vieira 4 , C. Calçada 5 , P. Costa 4 1 Hospital de Braga, Radiation Oncology, Braga, Portugal; 2 Hospital de Braga , Radiation Oncology , Braga , Portugal; 3 Hospital de Braga , Radiation Oncology, Braga , Portugal; 4 Júlio Teixeira SA - Instituto CUF , Radiation Oncology, Porto, Portugal; 5 Júlio Teixeira SA - Instituto CUF , Radiation Oncology , Porto , Portugal Purpose or Objective The aim of this study was to report the experience of a single center in the treatment of benign temporal bone paragangliomas with Robotic Stereotactic Radiosurgery. Materials and Methods Between August 2017 and July 2021, 8 patients with benign temporal bone paragangliomas were treated with Cyberknife® Robotic Stereotactic Radiosurgery in the Department of Radiation Oncology Júlio Teixeira SA, CUF Institute – Oporto, Portugal. Main endpoints included clinical response, local tumor control, and adverse radiation effects. Tumor response was assessed according to RECIST criteria on follow-up MRI images, and toxicities were classified based on CTCAE scale version 5.0. Results 7 patients with tympanojugular paragangliomas and 1 with tympanomastoid paraganglioma, were treated. The most common presenting symptoms were conductive hearing loss, followed by headache and hoarseness. Other symptoms reported were pulsatile tinnitus, left scapular contracture and left vocal cord paralysis. Half of the patients were diagnosed with recurrent tumors after surgery +/- embolization. The prescription dose ranged between 12 and 25Gy, delivered in 1 to 5 fractions (reference isodose 71 - 89%). The median treatment volume was 6.9 cc (range 0.84 – 39.21cc). PO-1202 Robotic radiosurgery for benign temporal bone paragangliomas: a single-center experience