7th ICHNO Abstract book

page 50 7 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 14 – 16 March 2019 Barcelona, Spain __________________________________________________________________________________________ 7th ICHNO

groups. A Cox proportional hazards model was used to identify independent predictors of survival, with adjustment for relevant covariates. Results In our data T-N tract involvement was significantly associated with distant recurrence and death. At 4 years, patients with T-N tract involved by disease have significantly more distant recurrence (40%) than patients without T-N tract involvement (22%, p=0.02). Patients with T-N tract involved are significantly more likely to die (76% versus 57%, p<0.0001). Among patients with positive neck lymph-node metastasis, T-N tract status was also significantly and negatively associated with OS (p=0.002).The competing risk Cox regression models indicate a significant triple risk of distant metastases with ‘T-N tract involvement’ (HR=3.13, with 95%CI: 1.15 to 8.33, p=0.03, adjusting for age) and a significant double risk of dead (HR=2.38, with 95%CI: 1.32 to 4.35, p=0.004). Conclusion This study highlight the negative impact of involvement of the T-N tract on patient survival. Further studies should confirm these results in order to include the T-N tract in the standard surgical treatment of OTSSC and to evaluate whether patients with disease in the T-N tract should have a different adjuvant therapy or follow- up scheme. PO-09 Clinical outcome of stereotactic body radiotherapy for lung-only oligometastatic HNSCC P. Bonomo 1 , I. Desideri 1 , C. Becherini 1 , M. Loi 1 , E. Orlandi 2 , N.A. Iacovelli 2 , V. Salvestrini 1 , M. Mariotti 1 , L. Visani 1 , L. Livi 1 1 Azienda Ospedaliero-Universitaria Careggi, Radiation Oncology, Florence, Italy; 2 Fondazione IRCSS Istituto Nazionale dei Tumori, Radiotherapy 2 Unit, Milan, Italy Purpose or Objective Very limited evidence is available on the role of local treatments for oligometastatic HNSCC. The aim of our work was to report the clinical outcome of SBRT for lung- only oligometastatic HNSCC in terms of safety and efficacy Material and Methods A lung-only oligometastastic disease was characterized by the presence of 1 to 5 pulmonary metastases. A multidisciplinary discussion was mandated for every patient, in particular to rule out differential diagnoses such as inflammatory nodules or second primary lung cancer. “De novo” and “induced” patterns were distinguished based on the timing of consideration for SBRT in respect to systemic treatment: “de novo” oligometastases were single lesions deemed amenable to local treatment only, whereas “induced” oligometastases were firstly managed with chemotherapy for recurrent/metastatic disease, with SBRT applied at time of disease oligoprogression, in all cases in order to defer the need of further systemic therapy. The following criteria were also mandatory upon inclusion in our analysis:

- PS 0-2

Local control of the irradiated lesion was assessed at 3 months after SBRT according to Recist criteria. Progression-free survival (PFS) was defined as the time from the last day of SBRT to disease progression or death from any cause. Overall survival (OS) was defined as the time from HNSCC diagnosis to death from any cause. Median PFS and OS were calculated. The relative estimates of PFS at 12 and 24 months were estimated by the Kaplan-Meier method. A log-rank test was employed to test whether age, primary site (oropharynx vs others), HPV status, initial disease stage, lesion size and oligometastatic pattern correlated with longer PFS. A multivariate Cox regression analysis was also performed. Results Twenty-seven patients were included in our study. Most (12/27, 44.4%) had oropharyngeal cancer. HPV positive disease was present in only 5 cases (18.5%). The majority had a “de novo” oligometastatic pattern (21/27, 77.7%). The most common SBRT regimen was 54 Gy in 3 fractions (7/27, 25.9%). The irradiated lesion showed PR or CR in 74% of cases. Overall, the median OS was of 47 months. At a median follow-up of 22 months after SBRT, median PFS was of 10 months. One and two-year PFS after SBRT were 57.4% and 29.2%, respectively (figure 1). At univariate analysis, only age > 70 years and T1/T2 initial stage correlated with better response after SBRT. At multivariate analysis, only limited T stage was still significant (initial T3/T4 had a HR for worse outcome of 5.38; 95% CI: 1.4-25.2, p=0.033) (figure 2). Acute toxicity was minimal, with G2 dysphagia in 2 patients.

- receipt of curatively-intended treatment for primary disease

- FNAB of index metastastic lesion or hypermetabolism at FDG PET

- SBRT dose equivalent to BED >100 Gy 10

- minimum 6 months follow-up time after SBRT