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A Comparative Analysis Between Sequential Boost and Integrated Boost Intensity Modulated Radiation Therapy for Locally Advanced Head and Neck Cancer
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Volume 93 Number 3S Supplement 2015 radiation therapy. Older age, black race, and higher grade of disease are associated with worse survival. Author Disclosure: S.L. James: None. C. Escott: None. A.B. Gardner: None. I. Amanam: None. J.K. Chan: None.
2724 Comparison of Hyperfractionated to Conventionally Fractionated Salvage IMRT for Locoregionally Advanced Recurrent Nasopharyngeal Carcinoma V.H. Lee,1 D.L. Kwong,1 S.C. Ng,1 K.O. Lam,1 H.C. Sze,1 P. Ho,2 W.W. Chan,1 L.S. Wong,1 D.K. Leung,1 A.S. Chan,1 F.T. Chan,1 K.S. Lau,1 and T.W. Leung1; 1The University of Hong Kong, Hong Kong, Hong Kong, 2 Queen Mary Hospital, Hong Kong, Hong Kong Purpose/Objective(s): Salvage intensity modulated radiation therapy (IMRT) for locoregionally advanced recurrent nasopharyngeal carcinoma (NPC) is always challenging due to the inherently high dose received by the nearby organs at risk (OARs) in the first course of radiation therapy. We prospectively studied the efficacy and safety of hyperfractionated (HF) IMRT and compared to a historical cohort treated with conventionally fractionated (CF) IMRT. Materials/Methods: Ten consecutive patients with locoregionally advanced (T3-T4, N0-N1, M0) NPC prospectively recruited and treated with induction chemotherapy gemcitabine/platinum for 3 cycles followed by 9-field (HF-IMRT) (64.8 Gy/54 fr/5.5 weeks, twice daily, interfractional interval 37 hours) concurrent with weekly platinum for 6 cycles. Objective response rate (ORR), local failure-free survival (LFFS), regional failurefree survival (RFFS), overall survival (OS) and treatment-related complications were compared to a historical cohort of another 10 patients in the same setting treated with 3 cycles of induction chemotherapy followed by CF-IMRT (60 Gy/30 fr/6 weeks). Results: Median age was 59.5 years (HF-IMRT) and 44.0 years (CFIMRT, PZ.764). After a median follow up of 27.9 months (range 5.2 to 69.0 months), ORR were 40.0% (HF-IMRT) and 30.0% (CF-IMRT, PZ.871) respectively. Median LFFS showed a trend in favor of HF-IMRT (33.6 months [95% CI 12.2e55.1 months] vs 14.8 months [95% CI 14.1e15.4 months], PZ.179). RFFS (40.8 months vs not reached, PZ.857) and OS (31.9 months vs 34.3 months, PZ.681) were not different between the 2 groups. Commonest chronic treatment-related complications were brain necrosis (10.0% in HF-IMRT vs 20.0% in CFIMRT; PZ.531), aspiration pneumonia (40.0% in HF-IMRT vs 20.0% in CF-IMRT; PZ.329) and hemorrhage (0% in HF-IMRT vs 30.0% in CFIMRT; PZ.060). Conclusion: HF-IMRT offered marginally better LFFS and relatively less treatment-related hemorrhage compared to CF-IMRT in locoregionally advanced recurrent NPC. Author Disclosure: V.H. Lee: None. D.L. Kwong: None. S.C. Ng: None. K. Lam: None. H.C. Sze: None. P. Ho: None. W.W. Chan: None. L. Wong: None. D.K. Leung: None. A.S. Chan: None. F. Chan: None. K. Lau: None. T. Leung: None.
2725 A Comparative Analysis Between Sequential Boost and Integrated Boost Intensity Modulated Radiation Therapy for Locally Advanced Head and Neck Cancer M.J. Stavas,1 G.R. Vlacich,2 J.J. Meshman,3 Y. Shyr,4 and A.J. Cmelak3; 1 Vanderbilt University, Nashville, TN, 2NRAD Medical Associates, Long Island, NY, 3Vanderbilt University Medical Center, Nashville, TN, 4 Vanderbilt University Medical Center, Nashville, TN Purpose/Objective(s): While technological advances in radiation treatment planning and delivery have improved the toxicity profile for patients with locally advanced head and neck cancer (LAHNC) undergoing concurrent chemoradiation, significant acute and long-term toxicities remain. Different treatment delivery techniques using intensity modulated radiation therapy (IMRT) have been developed including sequential boost and
simultaneous integrated boost (SIB) to minimize toxicity. How these techniques differ in treatment-related outcomes including acute and longterm toxicities remains unexplored. Materials/Methods: We performed a single institutional retrospective matched cohort analysis on patients with LAHNC treated with definitive chemoradiation therapy. Patients were divided by radiation treatment technique: sequential boost (nZ68) or SIB (nZ141). Contours, dose constraints, plan evaluation, and toxicity assessment were performed by a single experienced physician. Toxicities were graded weekly during treatment and at three month follow up intervals using the Common Terminology Criteria for Adverse Events. Local recurrence-free survival, disease-free survival and overall survival were estimated via Kaplan-Meier statistical method. Results: The median follow-up was 30.6 months. At 4 years, the estimated overall survival (OS) was 69.3% in the sequential boost cohort and 76.8% in the SIB cohort (PZ.13). Disease-free survival (DFS) was 63% and 69%, respectively (PZ.27). There were no significant differences in local, regional, or distant recurrence-free survival. In addition, there were no significant differences in relative weight loss (PZ.291), the rate of gastrostomy tube placement (PZ.494), or prolonged PEG tube dependence (PZ.465). Rates of grade 3 or 4 dysphagia (81% vs 55%) and dermatitis (78% vs 58%) were significantly higher in the SIB group (P<.001 and PZ.012). Moreover, a greater percentage of the SIB cohort did not receive the total prescribed dose due to acute toxicity (7% versus 0). Conclusion: There were no differences in disease-related outcomes including OS and DFS between the 2 treatment planning approaches. A higher rate of grade 3 and 4 radiation dermatitis and dysphagia were observed in the SIB group compared to sequential boost group. However, these toxicities did not translate into increased treatment-related breaks, weight loss, gastrostomy tube placement, or long-term PEG tube dependence. Additional investigation is necessary to further evaluate the cause of acute toxicity differences. A more detailed analysis of dose and volume statistics to the organs at risk, the impact of HPV positivity and the role of induction chemotherapy may further our understanding of the variables that impact acute and long term toxicity. Author Disclosure: M.J. Stavas: None. G.R. Vlacich: None. J.J. Meshman: None. Y. Shyr: None. A. Cmelak: None.
2726 Measuring Setup Error at Multiple Neck Levels in NPC: A Case for Variable Planning Target Volume Expansion Y. Loh, T. Cheo, I. Tham, K.M. Lee, and D. Chen; National University Cancer Institute (Singapore), Singapore, Singapore Purpose/Objective(s): To establish the magnitude of systematic and random setup errors (SEs) at the clivus, mid-neck, and supra-clavicular (SCF) region with image guided radiation therapy (IGRT) in NPC with recommendation for appropriate planning target volume (PTV) margins for each level. Materials/Methods: Thirty-six patients with NPC underwent radical IGRT to a dose of 70 Gy delivered over 33 fractions. Each had 9 scheduled cone beam computed tomography scans (CBCTs) done, consisting of 4 daily CBCTs in the first week followed by 5 weekly CBCTs. CBCTs are matched preferentially at the clivus in view of proximity to the nasopharynx. Each CBCT was reviewed to determine the SEs separately at the level of the clivus, C4, and C7 vertebral levels. The SEs were measured before CBCT correction (as the initial error), after CBCT correction (residual error) and recorded in the medio-lateral (ML), superior-inferior (SI) and antero-posterior (AP) axes. The 3-dimensional (3D) displacement was determined at each anatomical level as the square root of the quadratic sum of the error on each of the 3 axes. The errors were also analyzed separately to determine the systematic (S) and random (s) SEs. Van Herk’s formula (2.5S + 0.7s) was then used to arrive at the recommended PTV margin which would ensure 95% isodose coverage of the CTV for 90% of the patients.
Volume 93 Number 3S Supplement 2015 radiation therapy. Older age, black race, and higher grade of disease are associated with worse survival. Author Disclosure: S.L. James: None. C. Escott: None. A.B. Gardner: None. I. Amanam: None. J.K. Chan: None.
2724 Comparison of Hyperfractionated to Conventionally Fractionated Salvage IMRT for Locoregionally Advanced Recurrent Nasopharyngeal Carcinoma V.H. Lee,1 D.L. Kwong,1 S.C. Ng,1 K.O. Lam,1 H.C. Sze,1 P. Ho,2 W.W. Chan,1 L.S. Wong,1 D.K. Leung,1 A.S. Chan,1 F.T. Chan,1 K.S. Lau,1 and T.W. Leung1; 1The University of Hong Kong, Hong Kong, Hong Kong, 2 Queen Mary Hospital, Hong Kong, Hong Kong Purpose/Objective(s): Salvage intensity modulated radiation therapy (IMRT) for locoregionally advanced recurrent nasopharyngeal carcinoma (NPC) is always challenging due to the inherently high dose received by the nearby organs at risk (OARs) in the first course of radiation therapy. We prospectively studied the efficacy and safety of hyperfractionated (HF) IMRT and compared to a historical cohort treated with conventionally fractionated (CF) IMRT. Materials/Methods: Ten consecutive patients with locoregionally advanced (T3-T4, N0-N1, M0) NPC prospectively recruited and treated with induction chemotherapy gemcitabine/platinum for 3 cycles followed by 9-field (HF-IMRT) (64.8 Gy/54 fr/5.5 weeks, twice daily, interfractional interval 37 hours) concurrent with weekly platinum for 6 cycles. Objective response rate (ORR), local failure-free survival (LFFS), regional failurefree survival (RFFS), overall survival (OS) and treatment-related complications were compared to a historical cohort of another 10 patients in the same setting treated with 3 cycles of induction chemotherapy followed by CF-IMRT (60 Gy/30 fr/6 weeks). Results: Median age was 59.5 years (HF-IMRT) and 44.0 years (CFIMRT, PZ.764). After a median follow up of 27.9 months (range 5.2 to 69.0 months), ORR were 40.0% (HF-IMRT) and 30.0% (CF-IMRT, PZ.871) respectively. Median LFFS showed a trend in favor of HF-IMRT (33.6 months [95% CI 12.2e55.1 months] vs 14.8 months [95% CI 14.1e15.4 months], PZ.179). RFFS (40.8 months vs not reached, PZ.857) and OS (31.9 months vs 34.3 months, PZ.681) were not different between the 2 groups. Commonest chronic treatment-related complications were brain necrosis (10.0% in HF-IMRT vs 20.0% in CFIMRT; PZ.531), aspiration pneumonia (40.0% in HF-IMRT vs 20.0% in CF-IMRT; PZ.329) and hemorrhage (0% in HF-IMRT vs 30.0% in CFIMRT; PZ.060). Conclusion: HF-IMRT offered marginally better LFFS and relatively less treatment-related hemorrhage compared to CF-IMRT in locoregionally advanced recurrent NPC. Author Disclosure: V.H. Lee: None. D.L. Kwong: None. S.C. Ng: None. K. Lam: None. H.C. Sze: None. P. Ho: None. W.W. Chan: None. L. Wong: None. D.K. Leung: None. A.S. Chan: None. F. Chan: None. K. Lau: None. T. Leung: None.
2725 A Comparative Analysis Between Sequential Boost and Integrated Boost Intensity Modulated Radiation Therapy for Locally Advanced Head and Neck Cancer M.J. Stavas,1 G.R. Vlacich,2 J.J. Meshman,3 Y. Shyr,4 and A.J. Cmelak3; 1 Vanderbilt University, Nashville, TN, 2NRAD Medical Associates, Long Island, NY, 3Vanderbilt University Medical Center, Nashville, TN, 4 Vanderbilt University Medical Center, Nashville, TN Purpose/Objective(s): While technological advances in radiation treatment planning and delivery have improved the toxicity profile for patients with locally advanced head and neck cancer (LAHNC) undergoing concurrent chemoradiation, significant acute and long-term toxicities remain. Different treatment delivery techniques using intensity modulated radiation therapy (IMRT) have been developed including sequential boost and
simultaneous integrated boost (SIB) to minimize toxicity. How these techniques differ in treatment-related outcomes including acute and longterm toxicities remains unexplored. Materials/Methods: We performed a single institutional retrospective matched cohort analysis on patients with LAHNC treated with definitive chemoradiation therapy. Patients were divided by radiation treatment technique: sequential boost (nZ68) or SIB (nZ141). Contours, dose constraints, plan evaluation, and toxicity assessment were performed by a single experienced physician. Toxicities were graded weekly during treatment and at three month follow up intervals using the Common Terminology Criteria for Adverse Events. Local recurrence-free survival, disease-free survival and overall survival were estimated via Kaplan-Meier statistical method. Results: The median follow-up was 30.6 months. At 4 years, the estimated overall survival (OS) was 69.3% in the sequential boost cohort and 76.8% in the SIB cohort (PZ.13). Disease-free survival (DFS) was 63% and 69%, respectively (PZ.27). There were no significant differences in local, regional, or distant recurrence-free survival. In addition, there were no significant differences in relative weight loss (PZ.291), the rate of gastrostomy tube placement (PZ.494), or prolonged PEG tube dependence (PZ.465). Rates of grade 3 or 4 dysphagia (81% vs 55%) and dermatitis (78% vs 58%) were significantly higher in the SIB group (P<.001 and PZ.012). Moreover, a greater percentage of the SIB cohort did not receive the total prescribed dose due to acute toxicity (7% versus 0). Conclusion: There were no differences in disease-related outcomes including OS and DFS between the 2 treatment planning approaches. A higher rate of grade 3 and 4 radiation dermatitis and dysphagia were observed in the SIB group compared to sequential boost group. However, these toxicities did not translate into increased treatment-related breaks, weight loss, gastrostomy tube placement, or long-term PEG tube dependence. Additional investigation is necessary to further evaluate the cause of acute toxicity differences. A more detailed analysis of dose and volume statistics to the organs at risk, the impact of HPV positivity and the role of induction chemotherapy may further our understanding of the variables that impact acute and long term toxicity. Author Disclosure: M.J. Stavas: None. G.R. Vlacich: None. J.J. Meshman: None. Y. Shyr: None. A. Cmelak: None.
2726 Measuring Setup Error at Multiple Neck Levels in NPC: A Case for Variable Planning Target Volume Expansion Y. Loh, T. Cheo, I. Tham, K.M. Lee, and D. Chen; National University Cancer Institute (Singapore), Singapore, Singapore Purpose/Objective(s): To establish the magnitude of systematic and random setup errors (SEs) at the clivus, mid-neck, and supra-clavicular (SCF) region with image guided radiation therapy (IGRT) in NPC with recommendation for appropriate planning target volume (PTV) margins for each level. Materials/Methods: Thirty-six patients with NPC underwent radical IGRT to a dose of 70 Gy delivered over 33 fractions. Each had 9 scheduled cone beam computed tomography scans (CBCTs) done, consisting of 4 daily CBCTs in the first week followed by 5 weekly CBCTs. CBCTs are matched preferentially at the clivus in view of proximity to the nasopharynx. Each CBCT was reviewed to determine the SEs separately at the level of the clivus, C4, and C7 vertebral levels. The SEs were measured before CBCT correction (as the initial error), after CBCT correction (residual error) and recorded in the medio-lateral (ML), superior-inferior (SI) and antero-posterior (AP) axes. The 3-dimensional (3D) displacement was determined at each anatomical level as the square root of the quadratic sum of the error on each of the 3 axes. The errors were also analyzed separately to determine the systematic (S) and random (s) SEs. Van Herk’s formula (2.5S + 0.7s) was then used to arrive at the recommended PTV margin which would ensure 95% isodose coverage of the CTV for 90% of the patients.