ESTRO 2020 Abstract book

S485 ESTRO 2020

The interval between surgery and RT did not show influence on locoregional control rates in patients with head and neck cancer. However, doses < 60 Gy, and the total treatment time < 150 days were associated with lower locoregional control rates. PO-0812 Hypofractionated Chemoradiation in LAHNC; QOL, Toxicity and Local Control in Radiation courses. G. Ferraris 1 , D. Davalos 1 , D. Fernandez 1 , L. Caussa 1 , F. Díaz Vazquez 1 1 Centro Medico Deán Funes, Radiation Oncology, Córdoba, Argentina Purpose or Objective To report Quality of life (QOL), acute and chronic toxicity and efficacy of two hypofractionated chemoradiation courses in patients with locally advanced head and neck cancer (LAHNC) Material and Methods This is a retrospective analysis of 98 consecutive patients prospectively evaluated, treated between June 2016 to October 2018 with adjuvant or radical criteria, with hypofractionated regimens in 30(72 Gy) or 20(60 Gy) daily sessions; with VMAT technique and IGRT with concurrent chemotherapy mainly CDDP 40mg/ mt2 weekly. Planning target volumes (PTVs) doses to primary tumor and involved nodes for 30 and 20 fractions were: 72 Gy (2.4 Gy/fraction), and 60-62 Gy (3-3.1 Gy/fraction). Subclinical PTVs received simultaneously 54–60 Gy (1.8–2.0 Gy/fraction) and 48-54Gy (2.4-2.7 Gy/ fraction) over 6 and 4 weeks respectively. Toxicity was evaluated according to the Radiation Therapy and Oncology Group (RTOG) scale, QoL (using polls EORTC 35 and 30 pre and post radiation treatment in both arms) to 3, 6 and 12 months and local control evaluated with CT, MRI or PET CT. ANOVA test was used to compare toxicity and QoL parameters in both arms. Results The mean follow-up was 12.1 months in the 30 fractions (n: 46), and 7.3 months in 20 fractions (n: 52) branch; mean age was 61 years old with PS 0-1 in 99% of the patients. The most common diagnosed and treated areas were pharynx (38.4%) in the 60 Gy branch, and oral cavity in the 72 Gy arm (41%); with staging III (36.5%) - IV (39%) and III (30%) - IV (41%) respectively. Radio-chemotherapy was completed by 79% of the patients in the 60 Gy branch and 78% in the 72 Gy branch. When comparing both schemes, no significant differences were observed in the group of 20 fractions at the end of the treatment, resulting in mucositis G3 (50% vs. 28%) (p <0,221), esophageal toxicity (23% vs. 30%) (p<0.085) as similarly results in xerostomia and pain. At six months post treatment only one patient presented G3 esophageal toxicity in the 72 Gy branch. There were no significative differences in Global QoL in both groups according to the pre and post- treatment polls (p = 0,571). In 20 and 30 fractions the survival, local control (clinical or by image) and progression were; 71%, 66.7% and 23.6% vs. 61%, 75.1% and 21.6% respectively with no statistical significance (p = 0,974). DFS of 6 months and 7.9 months in the 60Gy and 72 Gy branch respectively with no statistical significance (p = 0,059) There were 3 deaths due to febrile neutropenia between the two branches and 1 death related to kidney toxicity in 30 fractions arm. Conclusion Hypofractionated chemoradiation with VMAT provides a convenient approach with acceptable local control rates and admissible profile toxicity for patients with LAHNC; achieving similar tumor response compared to conventional chemoradiation fractionation according to literature. We found no statistical differences in chronic toxicity and QoL between the two arms of treatments.

Conclusion Pretreatment SUV-N / SUV-T is a simple and useful marker for prognosticating DMFS in NPC patients treated by IMRT, which may help in tailoring treatment or designing future clinical trials. PO-0811 Influence of time between surgery and postoperative radiation therapy in head and neck cancer R. Franco 1 , D.M. Leandro 2 , K. Marco Aurélio 2 , G. De Castro Junior 3 , G. Marta 4 1 Instituto do Câncer do Estado de São Paulo ICESP- Universidade de São Paulo, Post-graduation Program of Department of Radiology and Oncology-, Sao Paulo, Brazil ; 2 Instituto do Câncer do Estado de São Paulo ICESP- Universidade de São Paulo, Department of Head and Neck Surgery, Sao Paulo, Brazil ; 3 Instituto do Câncer do Estado de São Paulo ICESP- Universidade de São Paulo, Department of Radiology and Oncology- Clinical Oncology Unit, Sao Paulo, Brazil ; 4 Hospital Sirio Libanes, Radiation Oncology, Sao Paulo, Brazil Purpose or Objective Radiation therapy (RT) has an important role at the treatment of patients with head and neck tumors, being frequently used as adjuvant therapy with the purpose to decrease locoregional recurrence rates. Beyond clinical tumor factors, the prognoses could be also affected by therapeutic variables such as the total treatment time and the interval time between surgery and adjuvant RT. It is not clear the optimal time to start RT after curative intent surgery without compromising the oncological outcomes. This study aimed to evaluate the effect of the delay in initiating adjuvant RT on the locoregional outcome of patients with head and neck cancer. Material and Methods This is a retrospective cohort study that included patients diagnosed with squamous cell carcinoma of head and neck submitted to surgical resection with curative intent followed by RT, with or without adjuvant chemotherapy, from January 2009 to January 2015. Data were collected from medical records. The time interval was considered from the date of surgery to the date of starting RT and dichotomized by the ROC curve method at 92th day. Possible sources of heterogeneity were also assessed through regression analysis, considering the potential effects of other variables on the locoregional outcome. Results A total of 168 patients were evaluated. The majority of them were male (n = 132; 78.6%), diagnosed with oral cavity cancer (n = 95; 56.5%) with median age of 62 years (range 41-92 years). About 93% of them had locally advanced disease clinical stage III/IV. The univariate analysis showed the following statistically significant factors were related to locoregional control: angiolymphatic invasion (p = 0.055), perineural invasion (p < 0.001), positive lymph nodes (p ≤ 0.001), extracapsular nodal extension (p = 0.014), length of RT < 30 days (p = 0.001), radiation dose to tumor bed < 60 Gy (p = 0.03) and KPS before RT < 70 (p = 0.001). The multivariate analysis showed KPS < 70 (HR = 2.058; CI95%: 1.060-3.992; p = 0.033), radiation dose to tumor bed < 60 Gy (HR = 6.523; CI95%:2.266-18.777; p = 0.001), positive lymph nodes (HR = 3.339; CI95%:1.350-8.255; p = 0.009) and perineural invasion (HR = 3.529; CI95%: 1.236-10.074; p = 0.018) as independent variables of lower locoregional control. The relapse-free survival rate was 66.4% for patients who initiated RT with more than 92 postoperative days versus 75.4% for those who initiated RT within 92 days (p=0.377). Patients whose total treatment time (period between the date of the surgery until the last day of RT) was longer than 150 days had a locoregional recurrence rate of 41.8%, whereas no patient with treatment duration inferior to 150 days had relapses (p = 0.001). Conclusion