ESTRO 38 Abstract book

S374 ESTRO 38

Overall, 137 pts were eligible for this retrospective analysis. With a median follow up of 70 months (range 12 - 143) actuarial rates at 2 and 5 years were respectively: LC 92.2% and 90.4%, DFS 83.1% and 77.2% and OS 92.4% and 82.8%. The median follow-up period was 70 months (range 12-143 months). T stage was dichotomized as T1- T2-T3 vs T4. At 5 years the group T1-T2-T3 reported a LC of 93%, a DFS of 79% and a OS of 88%, whereas T4 pts reported a LC, DFS and OS respectively of 56%, 50% and 78%. All outcomes (LC, DFS and OS) were significantly better with VMAT compared to conventional IMRT (Table 1). In particular T4-stage pts treated with VMAT fared similarly compared to pts with T1-T2-T3 stages treated with conventional IMRT (Figure 1). Regardless of RT technique, pts with a V95%> 95.5% had better LC (p=0.006). Pts with a D99%> 63.8 Gy had better LC (p=0.034) and OS (p=0.005). The threshold value of 43.2 cc of GTV T was prognostic for LC (p = 0.016). At multivariate analysis GTV T, RT technique (VMAT) and D99% resulted prognostic for LC (p=0.04).

disease. Median dose of prior photon based radiation was 60Gy (± SD: 10.4, range: 24-78Gy). Median time interval between prior radiation and recurrence was 6.33 years (SD: 3.67, range: 1.08 to 20 years). Median dose of CIRT at the time of re-radiation was 60GyE at 3 GyE per fraction. During re-radiation, 11 pts (21.6%) had G0 toxicity (no toxicity), 19 pts (37.3%) had G1, 19 pts (37.3%) had G2 and 2 pts (3.9%) had G3 toxicity. Median follow-up was 19 months (SD: 14.42, range: 2-57). Twenty one (41.2%) pts had stable disease and 30 pts (58.8%) tumor progression at the time of last follow up. Furthermore, 14 pts (27.5%) had no late toxicity, 9 (18%) pts had G1, 19 pts (37%) had G2 and 9 pts (17. 5%) had G3 late toxicities. Using Kaplan Meier method, estimated PFS (actuarial) at one, two and three years were 80%, 65.1% and 43.5% respectively. Estimated OS (actuarial) at one, two and three years were 90.2%, 69.1% and 54.5% respectively. The estimated mean and median PFS was 28.89 (SD: 3.06) and 25.00 (5.95) months respectively. In receiver operating curve (ROC) analyses, there was significant difference of median survival time after CIRT between the cut-off value of 34 cc of GTV in treated pts. The estimated median PFS in pts with GTV less than 34 cc and more than 34 cc were 34.00 (±3.37) and 13 months (±7.13) respectively (log rank test, p=0.038). Conclusion In re-radiation setting, CIRT is effective in controlling local progression of recurrent salivary gland tumors along with acceptable rates of acute and late toxicity. PO-0729 Prognostic factors analysis in a cohort of Nasopharyngeal cancer patients with 5-year follow-up N.A. Iacovelli 1 , A. Cavallo 2 , A. Cicchetti 3 , L. Ferella 1 , N. Facchinetti 1 , T. Giandini 2 , S. Meroni 2 , D.A. Romanello 1 , P. Bossi 4 , L. Licitra 4 , E. Pignoli 2 , C. Fallai 1 , E. Orlandi 1 1 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Radiotherapy Unit 2, Milan, Italy ; 2 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Medical Physics Unit, Milan, Italy ; 3 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Prostate Cancer Program, Milan, Italy ; 4 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, Head and Neck Medical Oncology Unit, Milan, Italy Purpose or Objective To evaluate clinical outcome and prognostic factors in a consecutive series of non-metastatic nasopharyngeal carcinoma (NPC) patients (pts) treated curatively with intensity modulated radiotherapy (RT) techniques (IMRT, Intensity Modulated Radiation Therapy or VMAT, Volumetric Modulated Arc Therapy) and chemotherapy (CT) with a minimum follow-up of 5 years. Material and Methods A retrospective analysis of consecutive non-metastatic NPC pts treated between 2005 and 2013 was conducted. According to WHO, 123 patients (89.8%) were suffering from undifferentiated NPC, 5 patients (3.6%), 2 patients (1.5%) and 7 patients (5.1%) were respectively affected by squamous cell carcinoma G1, G2 or G3. Two pts were in stage I (1.5%), 23 pts (16.8%) were in stage II, 38 pts (27.7%) in stage III, 29 pts (21.2%) in stage IVA and 45 pts (32.8%) in stage IVB. Five pts (3.6%) received RT alone: 1 pt in stage I and 4 pts in stage II. Of the remaining 132 pts (96.4%) (9 pts with stage II and 123 pts with stage III and IV) 30 patients (21.9%) received CT concomitant to RT and 102 patients (74.4%) were treated with induction CT followed by RT-CT. IMRT was given with standard fractionation at a total dose of 70 Gy. A dedicated software (VODCA, www.vodca.ch) was used to collect and analyze dosimetric parameters. Clinical outcomes investigated in the study were local control (LC), disease- free survival (DFS) and overall survival (OS). Kaplan-Meier analysis was performed for the outcomes considering dose and coverage parameters, staging, CT and RT technique. Results

Conclusion Although in a retrospective series, we demonstrated the prognostic value of some dose-volume parameters, potentially useful to improve planning procedure. In addition, for the first time in a non-endemic area, a threshold value of GTV T, prognostic for LC, has been confirmed. PO-0730 NTCP model for penetration/aspiration after (chemo)radiation including DVH parameters. A. Gawryszuk 1 , H.P. Van der Laan 1 , R.J.M. Steenbakkers 1 , J.G.M. Van den Hoek 1 , H.P. Bijl 1 , J.A. Langendijk 1 1 University Medical Center Groningen- Groningen, Department of Radiation Oncology, Groningen, The Netherlands Purpose or Objective Late aspiration, especially silent, is one of the most hazardous complications after (chemo)radiation ((CH)RT) for head and neck cancer, resulting in 3-year morbidity rates of approximately 20% and increased mortality. However, limited data exists on dose-effect relationship for late aspiration. Radiation doses to some of the swallowing organs at risk (SWOARs), such as pharyngeal constrictor muscles, are associated mainly with the subjective dysphagia measurements. The purposes of this analysis was to identify the best predictors of penetration/aspiration (as assessed on videofluoroscopy (VF)), after (CH)RT, using clinical data as well as DVH parameters. Material and Methods This prospective cohort study included 186 head and neck cancer patients receiving definitive (CH)RT. Patients underwent a comprehensive dysphagia assessment (including VF) at baseline and 6 months after treatment. 161 patients underwent VF at both time points and were included in this analysis. The primary endpoint was a Penetration Aspiration Scale (PAS) score ≥ 3