D. Fransen

Unilateral neck irradiation for well-lateralized oropharyngeal cancer

BACKGROUND AND PURPOSE To investigate the impact of unilateral neck irradiation (UNI) of well-lateralized oropharyngeal cancer (OPC) on outcome and toxicity. MATERIALS AND METHODS Unilateral neck IMRT was applied to 185 consecutive patients with well-lateralized OPC (restricted to tonsillar fossa, soft palate with at least 1cm from midline or lateral pharyngeal wall). Endpoints were regional control (RC), local control (LC), disease-free survival (DFS), overall survival (OS), and toxicity. RESULTS Six regional failures were reported (3.2%); 2 were contralateral (1.1%). The 5-year Kaplan-Meier estimates of RC, LC, DFS, and OS were 96%, 91%, 84%, and 70%, respectively. Feeding tube was given to 11.3%. Chemotherapy was significantly predictive for toxicity. However, no patient was still feeding tube dependent 6 weeks after treatment. Overall grade 3 late toxicity was 2.2%. Grade 3 xerostomia was reported in only 1 patient while no patient developed grade 3 dysphagia. CONCLUSION This largest study on unilateral neck IMRT for well-lateralized OPC showed excellent outcome and favorable toxicity profile. Given the increasing incidence of OPC, especially among younger patients, and the favorable results reported in the current study and by other investigators, expanding the indications for UNI still needs to be further investigated in prospective, preferably, randomized trials.

Single vocal cord irradiation: Image guided intensity modulated hypofractionated radiation therapy for T1a glottic cancer: Early clinical results

PURPOSE To report, from a retrospective analysis of prospectively collected data, on the feasibility, outcome, toxicity, and voice-handicap index (VHI) of patients with T1a glottic cancer treated by a novel intensity modulated radiation therapy technique developed at our institution to treat only the involved vocal cord: single vocal cord irradiation (SVCI). METHODS AND MATERIALS Thirty patients with T1a glottic cancer were treated by means of SVCI. Dose prescription was set to 16 × 3.63 Gy (total dose 58.08 Gy). The clinical target volume was the entire vocal cord. Setup verification was done by means of an online correction protocol using cone beam computed tomography. Data for voice quality assessment were collected prospectively at baseline, end of treatment, and 4, 6, and 12 weeks and 6, 12, and 18 months after treatment using VHI questionnaires. RESULTS After a median follow-up of 30 months (range, 7-50 months), the 2-year local control and overall survival rates were 100% and 90% because no single local recurrence was reported and 3 patients died because of comorbidity. All patients have completed the intended treatment schedule; no treatment interruptions and no grade 3 acute toxicity were reported. Grade 2 acute dermatitis or dysphagia was reported in only 5 patients (17%). No serious late toxicity was reported; only 1 patient developed temporary grade 2 laryngeal edema, and responded to a short-course of corticosteroid. The VHI improved significantly, from 33.5 at baseline to 9.5 and 10 at 6 weeks and 18 months, respectively (P<.001). The control group, treated to the whole larynx, had comparable local control rates (92.2% vs 100%, P=.24) but more acute toxicity (66% vs 17%, P<.0001) and higher VHI scores (23.8 and 16.7 at 6 weeks and 18 months, respectively, P<.0001). CONCLUSION Single vocal cord irradiation is feasible and resulted in maximal local control rate at 2 years. The deterioration in VHI scores was slight and temporary and subsequently improved to normal levels. Long-term follow-up is needed to consolidate these promising results.

OC-0266: Automated treatment plan generation for advanced stage NSCLC patients

Material and Methods: Based on treatment plans of 7 previously treated patients, the clinical protocol, and physician’s treatment goals and priorities, our in-house developed system for fully automated, multi-criterial plan generation was configured to generate VMAT plans for advanced stage NSCLC patients without human interaction. For 41 independent patients, treated between January and August 2015, automatic plan generation was then compared with manual plan generation, as performed in clinical routine. Differences in PTV coverage, dose conformality R50 (the ratio between the total volume receiving at least 50% of the prescribed dose and the PTV volume) and sparing of organs at risk were quantified, and their statistical significance was assessed using a Wilcoxon test.