ESTRO 2020 Abstract book

S471 ESTRO 2020

ESTRO 2020 Posters

Poster: Clinical track: Head and Neck

PO-0786 Comparison of the intra-arterial and systemic chemoradiotherapy for gingival carcinoma Y. Mukai 1 , I. Koike 1 , Y. Hayashi 2 , M. Sugiura 1 , T. Koizumi 2 , K. Mitsudo 2 , M. Hata 1 1 Yokohama City University Graduate School of Medicine, Radiation Oncology, Yokohama, Japan ; 2 Yokohama City University Graduate School of Medicine, Dentistry and Oral surgery, Yokohama, Japan Purpose or Objective The aim of this analysis was to compare the efficacy and toxicity between radiation therapy(RT) with concurrent retrograde super-selective intra-arterial chemotherapy (IACRT) and RT with or without concurrent systemic chemotherapy (SCRT) for gingival carcinoma (GC). Material and Methods We included 87 consecutive patients who were treated for GC ≥ stage III, from 2006 to 2018, in this retrospective analysis (IACRT group: n=66; SCRT group: n=21). Patients received external irradiation at a planned total dose of 60 Gy in 30 fractions. In the IACRT group, chemotherapy was started at the same time as RT. Cisplatin (5 mg/m 2 /day) and docetaxel (DOC; 10 mg/m 2 /week) were administered daily by infusion over a period of 1 hour, 5 days per week as a single course, for 6 weeks.In the SCRT group, 18 patients had chemotherapy with RT consisting of tegafur/gimeracil/oteracil potassium (TS-1, 80–120 mg/day, n=9), cetuximab (250–400 mg/m 2 , n=6), and tegafur–uracil (UFT; 300 mg/m 2 , n=2); and one patient had DOC (60 mg/m 2 ) + fluorouracil (100 mg). The other three patients received RT only. Results Median follow-up time was 24 (range: 1–124) months. At 3 years, the two groups significantly differed in overall survival (OS; IACRT: 78.75%, 95% confidence interval [CI]: 66.00–87.62; SCRT: 44.97%, 95% CI: 24.39–67.44; P = 0.0009), progression-free survival (PFS; IACRT: 75.64%, 95% CI: 62.69–85.17; SCRT: 42.65%, 95% CI: 20.52–68.18; P = 0.0023) and local control (LC; IACRT: 77.17%, 95% CI: 64.23–86.41; SCRT: 42.65%, 95% CI: 20.52–68.18; P = 0.0071) (Figure 1). In univariate analysis, age ≥ 65, decreased PS, clinical stage IV, and SCRT treatment were significantly associated with worse outcomes. In multivariate analysis, age ≥ 65 years, clinical stage IV, and SCRT were significantly correlated with poor OS. However, there was a significant difference in poor PFS and LC among patients who had decreased PS. In IACRT group developed significantly severe acute toxicities; ≥ Grade 3 leukocytopenia (P = 0.0057), dermatitis radiation (P = 0.0224), and dysphagia (P = 0.0026). However, all patients immediately recovered after treatment. In both groups, osteoradionecrosis (mandibular: n=13, maxillary: n=2) was the most common late toxicity.

Conclusion To our knowledge, this is the first report to compare outcomes between GC patients treated with IACRT and SCRT. IACRT is an effective and organ-preserving treatment for GC. PO-0787 Outcome comparison between pT4/N1b papillary thyroid cancer (PTC) and rpT4/N1b PTC after adjuvant RT C. Kim 1 , N.K. Lee 1 1 Korea University Anam Hospital, Radiation Oncology, Seoul, Korea Republic of Purpose or Objective The current study aimed to compare the treatment outcomes of adjuvant radiation therapy between patients with locoregionally advanced papillary thyroid carcinoma (pT4 or pN1b) and those with locoregionally recurrent papillary thyroid carcinoma (rpT4 or rpN1b). Material and Methods The data of 54 patients with thyroid papillary carcinoma who underwent adjuvant radiation therapy between 2001 and 2010 were analyzed retrospectively. Among the 54 patients treated with adjuvant radiation therapy, 34 had locoregionally advanced papillary thyroid carcinoma and 20 had locoregionally recurrent papillary thyroid carcinoma. The primary endpoints were the locoregional recurrence-free survival rate and distant metastasis-free survival rate. Results The median follow-up time was 111 months (range, 38 to 211 months) for all the 54 patients. The 15-year locoregional recurrence-free survival rate was 90.8% and 83.7% in patients with locoregionally advanced papillary thyroid carcinoma and those with locoregionally recurrent papillary thyroid carcinoma, respectively (p = 0.612). The 15-year distant metastasis-free survival rate was 97.0% and 63.0% in patients with locoregionally advanced papillary thyroid carcinoma and those with locoregionally recurrent papillary thyroid carcinoma, respectively (p = 0.028). Conclusion Adjuvant radiation therapy can achieve favorable locoregional recurrence-free survival rates in patients with locoregionally advanced papillary thyroid carcinoma and those with locoregionally recurrent papillary thyroid carcinoma. However, the distant metastasis-free survival