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OC-0504 A PREDICTIVE MODEL FOR TUBE FEEDING DEPENDENCE AFTER CURATIVE (CHEMO-) RADIATION IN HEAD AND NECK CANCER PATIENTS
S203
ESTRO 31
Purpose/Objective: To avoid severe xerostomia ((long-term salivary function <25% of baseline) the QUANTEC group (2010) defined dosevolume constraints for the dose to the parotid glands. These constraints imply that at least one parotid gland receives a mean dose < 20 Gy or that both glands receive a mean dose < 25 Gy. This analysis was conducted to assess whether the QUANTEC criteria prevent moderate-to-severe patient-rated xerostomia. Materials and Methods: This prospective study consisted of 351 patients treated with primary chemoradiation (CHRT) or radiotherapy (RT) for squamous cell head and neck cancer (HNSCC). All patients were subjected to a standard follow up program in which radiationinduced toxicity as well as quality of life was prospectively assessed. A total number of 182 patients were treated with 3D-CRT and 169 patients with IMRT. For all the patients, the dose volume data of the parotid glands were available. Patients in whom the QUANTEC criteria were met were classified as LOW RISK and, if not, as HIGH RISK. Results: 128 patients (41%) were classified as LOW RISK patients. Despite the use of IMRT in 61 patients (36%) the QUANTEC criteria were met. Sparing of the parotid glands with IMRT was significantly more difficult in patients with lymph node metastases and in patients with nasopharyngeal and oropharyngeal tumours. HIGH RISK patients reported 65%, 52%, 47% and 54% moderate-to-severe xerostomia at 6, 12, 18 and 24 months, respectively. This was for the LOW RISK patients, these figures were 32%, 25%, 15% and 16%, respectively (Figure 1). The estimate risk of moderate-to severe xerostomia of elderly patients (>65 years) and patients with pre-existing minor patient-rated xerostomia at baseline was beyond 20% even when the QUANTEC criteria were met.
Materials and Methods: 610 patients with HNC treated with curative (chemo-) radiation were included in this study. In all patients, tube feeding dependence was scored prospectively. To design the model, univariate and multivariate logistic regression analysis with an extended bootstrapping technique were carried out in a development cohort (n=427) with TUBEM6 as the primary endpoint. The model was externally validated (validation cohort; n=183) and, in addition, we tested if the model could also be extrapolated to later time points (12, 18 and 24 months). Results: In the development cohort, 55 patients (12.9%) were tube feeding dependent at 6 months after completion of treatment. In the development cohort, 17% of patients were treated with chemoradiation and 33% of patients had advanced tumour stages (Tstage: T3 or T4). In the validation cohort 19% of patients were treated with chemoradiation and 42% of patients had advanced tumour stages. In the multivariate analysis, moderate to severe weight loss prior to treatment, advanced T-stage and positive N-stage turned out to be the most important prognostic factors for TUBEM6. Model performance at external validation was good with an Area under the Curve of 0.86 and 0.82 in the development and validation cohort, respectively. The nomogram for this predictive model is shown in Figure 1. Subsequently, the total population of the development cohort was divided into three risk groups based on the risk on TUBEM6. Patients were considered low risk, intermediate risk or high risk in case the estimated NTCP-value for TUBEM6 was 5%, >5-15%, or >15% respectively. The TUBEM6-based risk groups significantly correlated with tube feeding dependence at 12, 18 and 24 months (p<0.001 at all time points).
Figure 1: Patient-rated moderate-to-severe xerostomia stratified by RISK group according to QUANTEC. The p-values refer to the chisquare test, to test for significant differences between HIGH and LOW RISK patients.
Figure 1: Nomogram for tube feeding dependence to determine NTCP values for each individual patient.
Conclusions: In current practice, only one third of the patients treated with IMRT fulfilled the QUANTEC dose contraints. Although significantly lower rates of radiation-induced patient-rated xerostomia were found among patients in whom the QUANTEC criteria were met, the QUANTEC criteria do not completely protect against xerostomia. Particularly in elderly patients and patients already suffering from minor xerostomia at baseline. OC-0504 A PREDICTIVE MODEL FOR TUBE FEEDING DEPENDENCE AFTER CURATIVE (CHEMO-) RADIATION IN HEAD AND NECK CANCER PATIENTS K. Wopken1, H.P. Bijl1, P. Doornaert2, M.E.M.C. Christianen1, S.F. Oosting3, D.H. Rietveld2, C. Schilstra1, R.J.H.M. Steenbakkers1, I.M. Verdonck-de Leeuw2, J.A. Langendijk1 1 University of Groningen / University Medical Center Groningen, Department of Radiation Oncology, Groningen, The Netherlands 2 VU University Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands 3 University of Groningen / University Medical Center Groningen, Department of Medical Oncology, Groningen, The Netherlands Purpose/Objective: The purpose of this multicenter prospective cohort study was to develop a predictive model for tube feeding dependence 6 months (TUBEM6) after curative (chemo-) radiation in head-and-neck cancer (HNC) patients based on pre-treatment and treatment characteristics that can be used to select patients for preventative measures, for example swallowing exercises or swallowing sparing IMRT. This predictive model was validated in an external independent prospective cohort.
Conclusions: We established an externally validated predictive model for tube feeding dependence after definitive (chemo-) radiation that can be used to predict TUBEM6 but also persistent tube feeding dependence at later time points. This model can be used to select patients for preventive measures. OC-0505 A PREDICTIVE MODEL FOR DYSPHAGIA DURING IMRT IN HEAD AND NECK CANCER : INTRODUCTION OF THE EMLASSO TECHNIQUE K. De Ruyck1, F. Duprez2, J. Werbrouck1, N. Sabbe3, S. De Langhe1, T. Boterberg2, I. Madani2, O. Thas3, W. De Neve2, H. Thierens1 1 Universiteit Gent, Medical Physics, Gent, Belgium 2 Universiteit Gent, Radiation Oncolgy, Gent, Belgium 3 Universiteit Gent, Applied Mathematics, Gent, Belgium Purpose/Objective: In the last decade, more aggressive treatment schedules for head and neck cancer have improved tumor control and survival. However, these therapies have come to the expense of increased toxicity. Despite substantial research efforts, predictive models identifying patients at risk for acute or persistent dysphagia after chemoradiotherapy are still unavailable. Therefore, the purpose of this study was to construct a multi-component model for the prediction of acute dysphagia in head and neck cancer patients receiving chemoradiotherapy. Furthermore, the use of the EMLasso technique for model selection was illustrated. Materials and Methods: Data were available for 201 head and neck cancer patients treated with intensity-modulated radiation therapy (IMRT). Radiation induced dysphagia was scored prospectively using the CTCAE v.3.0 scale. For model building, clinical data (gender, age, nicotine and alcohol use, diabetes, tumor location), treatment parameters (chemotherapy, surgery, lymph node dissection, overall
ESTRO 31
Purpose/Objective: To avoid severe xerostomia ((long-term salivary function <25% of baseline) the QUANTEC group (2010) defined dosevolume constraints for the dose to the parotid glands. These constraints imply that at least one parotid gland receives a mean dose < 20 Gy or that both glands receive a mean dose < 25 Gy. This analysis was conducted to assess whether the QUANTEC criteria prevent moderate-to-severe patient-rated xerostomia. Materials and Methods: This prospective study consisted of 351 patients treated with primary chemoradiation (CHRT) or radiotherapy (RT) for squamous cell head and neck cancer (HNSCC). All patients were subjected to a standard follow up program in which radiationinduced toxicity as well as quality of life was prospectively assessed. A total number of 182 patients were treated with 3D-CRT and 169 patients with IMRT. For all the patients, the dose volume data of the parotid glands were available. Patients in whom the QUANTEC criteria were met were classified as LOW RISK and, if not, as HIGH RISK. Results: 128 patients (41%) were classified as LOW RISK patients. Despite the use of IMRT in 61 patients (36%) the QUANTEC criteria were met. Sparing of the parotid glands with IMRT was significantly more difficult in patients with lymph node metastases and in patients with nasopharyngeal and oropharyngeal tumours. HIGH RISK patients reported 65%, 52%, 47% and 54% moderate-to-severe xerostomia at 6, 12, 18 and 24 months, respectively. This was for the LOW RISK patients, these figures were 32%, 25%, 15% and 16%, respectively (Figure 1). The estimate risk of moderate-to severe xerostomia of elderly patients (>65 years) and patients with pre-existing minor patient-rated xerostomia at baseline was beyond 20% even when the QUANTEC criteria were met.
Materials and Methods: 610 patients with HNC treated with curative (chemo-) radiation were included in this study. In all patients, tube feeding dependence was scored prospectively. To design the model, univariate and multivariate logistic regression analysis with an extended bootstrapping technique were carried out in a development cohort (n=427) with TUBEM6 as the primary endpoint. The model was externally validated (validation cohort; n=183) and, in addition, we tested if the model could also be extrapolated to later time points (12, 18 and 24 months). Results: In the development cohort, 55 patients (12.9%) were tube feeding dependent at 6 months after completion of treatment. In the development cohort, 17% of patients were treated with chemoradiation and 33% of patients had advanced tumour stages (Tstage: T3 or T4). In the validation cohort 19% of patients were treated with chemoradiation and 42% of patients had advanced tumour stages. In the multivariate analysis, moderate to severe weight loss prior to treatment, advanced T-stage and positive N-stage turned out to be the most important prognostic factors for TUBEM6. Model performance at external validation was good with an Area under the Curve of 0.86 and 0.82 in the development and validation cohort, respectively. The nomogram for this predictive model is shown in Figure 1. Subsequently, the total population of the development cohort was divided into three risk groups based on the risk on TUBEM6. Patients were considered low risk, intermediate risk or high risk in case the estimated NTCP-value for TUBEM6 was 5%, >5-15%, or >15% respectively. The TUBEM6-based risk groups significantly correlated with tube feeding dependence at 12, 18 and 24 months (p<0.001 at all time points).
Figure 1: Patient-rated moderate-to-severe xerostomia stratified by RISK group according to QUANTEC. The p-values refer to the chisquare test, to test for significant differences between HIGH and LOW RISK patients.
Figure 1: Nomogram for tube feeding dependence to determine NTCP values for each individual patient.
Conclusions: In current practice, only one third of the patients treated with IMRT fulfilled the QUANTEC dose contraints. Although significantly lower rates of radiation-induced patient-rated xerostomia were found among patients in whom the QUANTEC criteria were met, the QUANTEC criteria do not completely protect against xerostomia. Particularly in elderly patients and patients already suffering from minor xerostomia at baseline. OC-0504 A PREDICTIVE MODEL FOR TUBE FEEDING DEPENDENCE AFTER CURATIVE (CHEMO-) RADIATION IN HEAD AND NECK CANCER PATIENTS K. Wopken1, H.P. Bijl1, P. Doornaert2, M.E.M.C. Christianen1, S.F. Oosting3, D.H. Rietveld2, C. Schilstra1, R.J.H.M. Steenbakkers1, I.M. Verdonck-de Leeuw2, J.A. Langendijk1 1 University of Groningen / University Medical Center Groningen, Department of Radiation Oncology, Groningen, The Netherlands 2 VU University Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands 3 University of Groningen / University Medical Center Groningen, Department of Medical Oncology, Groningen, The Netherlands Purpose/Objective: The purpose of this multicenter prospective cohort study was to develop a predictive model for tube feeding dependence 6 months (TUBEM6) after curative (chemo-) radiation in head-and-neck cancer (HNC) patients based on pre-treatment and treatment characteristics that can be used to select patients for preventative measures, for example swallowing exercises or swallowing sparing IMRT. This predictive model was validated in an external independent prospective cohort.
Conclusions: We established an externally validated predictive model for tube feeding dependence after definitive (chemo-) radiation that can be used to predict TUBEM6 but also persistent tube feeding dependence at later time points. This model can be used to select patients for preventive measures. OC-0505 A PREDICTIVE MODEL FOR DYSPHAGIA DURING IMRT IN HEAD AND NECK CANCER : INTRODUCTION OF THE EMLASSO TECHNIQUE K. De Ruyck1, F. Duprez2, J. Werbrouck1, N. Sabbe3, S. De Langhe1, T. Boterberg2, I. Madani2, O. Thas3, W. De Neve2, H. Thierens1 1 Universiteit Gent, Medical Physics, Gent, Belgium 2 Universiteit Gent, Radiation Oncolgy, Gent, Belgium 3 Universiteit Gent, Applied Mathematics, Gent, Belgium Purpose/Objective: In the last decade, more aggressive treatment schedules for head and neck cancer have improved tumor control and survival. However, these therapies have come to the expense of increased toxicity. Despite substantial research efforts, predictive models identifying patients at risk for acute or persistent dysphagia after chemoradiotherapy are still unavailable. Therefore, the purpose of this study was to construct a multi-component model for the prediction of acute dysphagia in head and neck cancer patients receiving chemoradiotherapy. Furthermore, the use of the EMLasso technique for model selection was illustrated. Materials and Methods: Data were available for 201 head and neck cancer patients treated with intensity-modulated radiation therapy (IMRT). Radiation induced dysphagia was scored prospectively using the CTCAE v.3.0 scale. For model building, clinical data (gender, age, nicotine and alcohol use, diabetes, tumor location), treatment parameters (chemotherapy, surgery, lymph node dissection, overall