6th ICHNO Abstract Book

page 32 6 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 16 – 18 March 2017 Barcelona, Spain __________________________________________________________________________________________ 6th ICHNO

mentally stressing. The total waiting time consists of delay before the referral to the specialist, delay from the referral to the diagnosis, and then the delay before the treatment. Material and Methods The Finnish national Head and Neck Oncology working group has evaluated the waiting time of head and neck cancer patients at the university hospital level bi-annually starting 2012 and taking a two-month period annually. At Turku University Hospital the waiting times were analysed in more detail starting from the year 2013 by analysing all the new patients referred to the tumour board meeting in October and November each year. Results At national level the waiting time from the first referral to the beginning of the treatment varied depending on the treatment modality and also depending on the hospital. In the latest analysed time period the waiting time varied from 15 to 45 days for patients receiving surgical treatment and from 31 to 83 days for those having definitive oncological therapy. In general the waiting time has slightly decreased from 2012 with a couple of exceptions. During this period Turku University Hospital has introduced a diagnostic package for head and neck cancer patients and the waiting time has decreased especially for the patients whose diagnosis was known at the time of referral. Conclusion The data from the national follow-up study will be presented. The presentation includes more detailed data from Turku University Hospital including the system of diagnostic package. PO-064 Normal tissue complication probability model for tube feeding dependence 6 months after radiotherapy N. Kanayama 1 , R.G.J. Kierkels 2 , R.J.H.M. Steenbakkers 2 , A. Van der Schaaf 2 , M. Miyazaki 1 , T. Fujii 3 , K. Nishiyama 4 , J.A. Langendijk 2 , T. Teshima 1 1 Osaka Medical Center for Cancer and Cardiovascular Diseases, Department of Radiation Oncology, Osaka, Japan 2 University of Groningen- University Medical Center Groningen, Department of Radiation Oncology, Groningen, The Netherlands 3 Osaka Medical Center for Cancer and Cardiovascular Diseases, Department of Otolaryngology- Head and Neck Surgery, Osaka, Japan 4 Yao Municipal Hospital, Department of Radiation Oncology, Yao, Japan Purpose or Objective A multivariable normal tissue complication probability (NTCP) model for tube feeding dependence 6 months after radiotherapy (TUBEM6) was published in “Radiotherapy and Oncology” 2014. The purpose of this study is to externally validate the published NTCP model for TUBEM6 and to develop NTCP model for TUBEM6 of our institute. Material and Methods This study included 122 patients of pharyngeal or laryngeal cancer treated by definitive intensity modulated radiotherapy (IMRT). The median total dose was 69.96 Gy/33 fr and the median dose to elective area was 45 Gy/25 fr. One hundred and one (83%) patients received chemoradiotherapy. We omitted level Ib, except in case of deep invasion to the oral cavity or highly suspicious lymph node for metastasis on level Ib. The organs at risk relating to swallowing dysfunction (pharyngeal constrictor muscle, cricopharyngeal inlet, supraglottic larynx, glottis area, oral tongue and anterior oropharynx) were contoured according to the consensus guideline published in 2015. The external validity was assessed by the

calibration curve using the Hosmer-Lemeshow test. The discriminative ability of the model was calculated using the area under the curve (AUC) and the (pseudo) explained variance was measured with the Nagelkerke’s R 2 . A backward approach was used to select the most predictive variables in the multivariable logistic regression analysis, out of variables which were significant in the univariable analysis. Results The prevalence of TUBEM6 was 5.7% in the cohort of our institute. When we calculate by the published NTCP model, the mean predicted value of TUBEM6 was 12.2% (95% CI: 8.3%-16.0%). Using the published NTCP model, Nagelkerke’s R 2 was 0.06. The AUC was 0.79 and the Hosmer-Lemeshow chi 2 was 9.3 ( p = 0.320). One hundred and six (87 %) patients had bilateral level Ib omitted from elective nodal area. The group where bilateral level Ib was omitted (omitting level Ib group) had lower TUBEM6 compared with the group where level Ib was included in the elective nodal area (including level Ib group; 3.8% vs. 18.8%, p = 0.043). In omitting level Ib group, there was significant reduction in the mean dose to the oral tongue compared with including level Ib group (35.3 Gy vs. 48.8 Gy, p < 0.001). In multivariable analysis, the most predictive factors for TUBEM6 in our institute were the mean dose to the supraglottic larynx, the contralateral parotid, and the oral tongue. In the NTCP model of our institute, Nagelkerke’s R 2 was 0.36. The AUC was 0.89 and the Hosmer-Lemeshow chi 2 was 4.64 ( p = 0.795). 95% CI of the predicted value of TUBEM6 was 3.7%-7.7%.

Conclusion The prevalence of TUBEM6 was lower than expected in the published NTCP model. However, the discriminative ability and calibration was good. The mean dose to the supraglottic larynx, the contralateral parotid and the oral tongue play important role in TUBEM6. Neck irradiation to the elective nodal area without level Ib contributes to lower TUBEM6. PO-065 Survival outcomes in Unknown Primary with nodal metastases and role of Radiation therapy A. Srivastava 1 , R. Bhalavat 2 , M. Chandra 2 , V. Pareek 2 1 Jupiter Hospital, Radiation Oncology, Navi Mumbai, India 2 Jupiter Hospital, Radiation Oncology, Thane, India Purpose or Objective Unknown primary with neck nodal metastases forms a grey area in oncology wherein the treatment options are limited and the outcomes vary with the modality chosen for the same. Unknown primaries especially in head and neck carcinoma require thorough evaluation and radiation therapy to the neck nodal metastases forms an important treatment in the armamentarium available for better survival outcomes. In our retrospective study at our center, we evaluated and present the survival outcomes