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Dosimetric Predictors of Hypothyroidism After Radical Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma
International Journal of Radiation Oncology Biology Physics
912 Abstract 203; Table 1 Multivariate regression outputs showing hazard ratios for AJCC N stage, pN, and LNR groups with 95% confidence intervals. AJCC N stage HR N1 N2a N2b N2c N3
1.98 1.95 2.85 3.78 2.52
(95% CI) pN HR
(95% CI)
LNR
HR
(95% CI)
(1.81-2.16) 1 1.78 (1.62-1.95) 0-6% 1.81 (1.66-1.98) (1.72-2.42) 2-5 2.53 (2.32- 2.75) 6%-12.5% 2.52 (2.29 -2.77) (2.66-3.16) >5 4.64 (4.18 -5.14) 12.5% 3.69 (3.37 -4.05) (3.30-4.15) (2.05-3.28)
and site-specific analyses. Future modifications of the nodal staging system should be based on the lymph node status, with consideration given to a separate system for oropharyngeal cancers. Patients with more than 5 positive nodes have significantly worse survival in all subsites and should be considered for alternative treatment regimens. Author Disclosure: T. Roberts: None. A.D. Colevas: None. W. Hara: None. F. Holsinger: None. I. Oakley-Girvan: None. V. Divi: None.
204 Dosimetric Predictors of Hypothyroidism After Radical Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma V.H. Lee,1 A.S. Chan,2 C.W. Choi,3 D.L. Kwong,4 K.O. Lam,4 C.C. Tong,5 H.C. Sze,4 S.C. Ng,5 and T.W. Leung5; 1Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong, 2Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong, 3Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong, Hong Kong, 4The University of Hong Kong, Hong Kong, Hong Kong, 5 Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong Purpose/Objective(s): We investigated for dosimetric predictors of hypothyroidism after radical intensity modulated radiation therapy (IMRT) for nonmetastatic nasopharyngeal carcinoma (NPC). Materials/Methods: Patients with nonmetastatic NPC treated with radical IMRT from 2008 to 2013 were reviewed. They were regularly monitored clinically with serum thyroid function tests before and after IMRT. Univariable and multivariable analyses were performed for demographic and dosimetric predictors of biochemical and clinical hypothyroidism. Results: A total of 149 patients fulfilled eligibility criteria. After a median follow-up duration of 3.1 years (range, 1.3-8.2 years), 33 patients (22.1%) and 21 patients (14.1%) developed biochemical and clinical hypothyroidism, respectively. Eight patients (24.2%) who had biochemical hypothyroidism developed clinical hypothyroidism later. Univariable and multivariable analyses revealed that volume of the thyroid (PZ.002, multivariable), VS60 (the absolute thyroid volume spared from 60 Gy or less) (P<.001, multivariable), and VS45 (P<.001, multivariable) of the thyroid were significant predictive factors of biochemical hypothyroidism. The freedom from biochemical hypothyroidism was longer for those whose VS6010 mL (mean 90.9 months vs 62.6 months; P<.001) and VS455 mL (mean 91.9 months vs 65.2 months; PZ.001). Similarly, multivariable analyses revealed that VS60 (PZ.001) and VS45 (PZ.003) were significant predictors of clinical hypothyroidism. The freedom from clinical hypothyroidism was longer for those whose VS6010 mL (91.5 months vs 73.3 months, PZ.002) and VS455 mL (91.5 months vs 75.9 months, PZ.007). Receiver-operating characteristics (ROC) analyses revealed that the areaunder-the-curve (AUC) value for VS60 was significantly higher than that for VS45 for both biochemical (0.751 vs 0.660; PZ.009) and clinical hypothyroidism (0.718 vs 0.607; PZ.007), respectively. Conclusion: VS60 and VS45 of the thyroid significantly predicted postIMRT hypothyroidism and should be considered important priorities of dose constraints during IMRT optimisation for NPC. Author Disclosure: V.H. Lee: None. A.S. Chan: None. C. Choi: None. D.L. Kwong: None. K. Lam: None. C. Tong: None. H.C. Sze: None. S.C. Ng: None. T. Leung: None.
205 Clinical Presentation of Oropharyngeal Squamous Cell Carcinoma in the Modern Era: Does Risk Stratification Using Human Papillomavirus and Smoking Status Matter? M.J. Amsbaugh,1 M.B. Yusuf,2 E. Cash,1 C.L. Silverman,1 J. Bumpous,1 C.A. Perez,1 R. Bert,1 R. Redman,1 and N.E. Dunlap1; 1University of Louisville, Louisville, KY, 2University of Louisville School of Medicine, Louisville, KY Purpose/Objective(s): Patterns of cervical lymph node metastases (LNMs) in patients with oropharyngeal squamous cell carcinoma (OPSCC) have historically been described. Here we compare the distribution of cervical LNMs in the human papillomavirus (HPV) era to historical controls. We also evaluated the influence of HPV and smoking status on the clinical presentation of OPSCC. Materials/Methods: All patients with OPSCC presenting to our institutional multidisciplinary clinic from January 2010 to June 2015 were reviewed from a prospective database. Subsite, stage, smoking status, and involved anatomical nodal levels were tabulated. Variance in clinical presentation was examined using X2, Kruskal-Wallis, Mann-Whitney, and logistic regression analyses. Results: Of 291 patients, HPV/p16 status was available for 243. Preliminary analyses confirmed that patients could be grouped based on anatomical site (Group 1: tonsil, base of tongue [BOT], vallecula, nZ217; Group 2: pharyngeal wall, palate, and other nZ26) and risk level (low risk: HPV/p16 positive and 10 pack-year history of smoking, nZ78; intermediate risk: HPV/p16 positive and >10 pack-year history of smoking, nZ82; and high risk: HPV/p16 negative, nZ80). Overall, 188 patients (77.3%) had at least 1 cervical LNM at time of presentation (99.4% ipsilateral, 16.5% contralateral). Locally advanced tumor stages were uncommon at presentation (22.2% T1, 37.0% T2, 26.7% T3, 10.7% T4a, and 2.5% T4b); however, advanced nodal disease was more common (22.6% N0, 14.8% N1, 7.0% N2a, 39.1% N2b, 11.9% N2c, and 4.5% N3). Patients who were current smokers were more likely to present with metastases to level IIa than were nonsmokers (odds ratio [OR]Z4.56, PZ.032). Rates of HPV/p16 positivity (P<.001), never having smoked (PZ.016), and cervical LNM (PZ.023) were significantly higher for patients in Group 1. Low-risk Group 1 patients presented with nodal stage N2a at a much higher than expected frequency (PZ.007), and high-risk patients presented with tumor stage T4 at a much higher than expected frequency (PZ.003). Previous smokers with a BOT subsite were more likely to have clinically positive ipsilateral necks than nonsmokers (ORZ1.8, PZ.038). There were no significant differences in T stage or N stage based on HPV/p16 positivity or smoking (P>.05). Furthermore, distribution of cervical LNMs was not associated with HPV/ p16 positivity, risk group, or anatomical group (P>.05). When data were compared to historical series, no significant differences were seen in the patterns of cervical lymph node metastases for patients with OPSCC. Conclusion: HPV/p16 positivity, smoking status, risk group, and anatomical group influenced the clinical presentation of patients with OPSCC. Historical series describing the patterns of cervical LNMs in patients with OPSCC remain clinically relevant. Author Disclosure: M.J. Amsbaugh: Employee; University of Louiville. M.B. Yusuf: None. E. Cash: None. C.L. Silverman: None. J. Bumpous: None. C.A. Perez: Employee; University of Louiville. R. Bert: None. R. Redman: None. N.E. Dunlap: Honoraria; Osler.
206 Demographics, Disparities, and Survival in Young Patients With Oral Cavity Squamous Cell Carcinoma: A Population-Level Analysis of 3828 Cases K. Zhan, E.A. Nicolli, and T. Day; Medical University of South Carolina, Charleston, SC Purpose/Objective(s): To characterize and identify prognosticators in oral cavity squamous cell carcinomas (OCSCC) in young patients. To determine whether type of hospital and insurance status correlates with survival. Materials/Methods: We conducted a retrospective review of the National Cancer Data Base from 1998 to 2012 of OCSCC in patients younger than
912 Abstract 203; Table 1 Multivariate regression outputs showing hazard ratios for AJCC N stage, pN, and LNR groups with 95% confidence intervals. AJCC N stage HR N1 N2a N2b N2c N3
1.98 1.95 2.85 3.78 2.52
(95% CI) pN HR
(95% CI)
LNR
HR
(95% CI)
(1.81-2.16) 1 1.78 (1.62-1.95) 0-6% 1.81 (1.66-1.98) (1.72-2.42) 2-5 2.53 (2.32- 2.75) 6%-12.5% 2.52 (2.29 -2.77) (2.66-3.16) >5 4.64 (4.18 -5.14) 12.5% 3.69 (3.37 -4.05) (3.30-4.15) (2.05-3.28)
and site-specific analyses. Future modifications of the nodal staging system should be based on the lymph node status, with consideration given to a separate system for oropharyngeal cancers. Patients with more than 5 positive nodes have significantly worse survival in all subsites and should be considered for alternative treatment regimens. Author Disclosure: T. Roberts: None. A.D. Colevas: None. W. Hara: None. F. Holsinger: None. I. Oakley-Girvan: None. V. Divi: None.
204 Dosimetric Predictors of Hypothyroidism After Radical Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma V.H. Lee,1 A.S. Chan,2 C.W. Choi,3 D.L. Kwong,4 K.O. Lam,4 C.C. Tong,5 H.C. Sze,4 S.C. Ng,5 and T.W. Leung5; 1Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong, 2Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong, 3Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong, Hong Kong, 4The University of Hong Kong, Hong Kong, Hong Kong, 5 Department of Clinical Oncology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong Purpose/Objective(s): We investigated for dosimetric predictors of hypothyroidism after radical intensity modulated radiation therapy (IMRT) for nonmetastatic nasopharyngeal carcinoma (NPC). Materials/Methods: Patients with nonmetastatic NPC treated with radical IMRT from 2008 to 2013 were reviewed. They were regularly monitored clinically with serum thyroid function tests before and after IMRT. Univariable and multivariable analyses were performed for demographic and dosimetric predictors of biochemical and clinical hypothyroidism. Results: A total of 149 patients fulfilled eligibility criteria. After a median follow-up duration of 3.1 years (range, 1.3-8.2 years), 33 patients (22.1%) and 21 patients (14.1%) developed biochemical and clinical hypothyroidism, respectively. Eight patients (24.2%) who had biochemical hypothyroidism developed clinical hypothyroidism later. Univariable and multivariable analyses revealed that volume of the thyroid (PZ.002, multivariable), VS60 (the absolute thyroid volume spared from 60 Gy or less) (P<.001, multivariable), and VS45 (P<.001, multivariable) of the thyroid were significant predictive factors of biochemical hypothyroidism. The freedom from biochemical hypothyroidism was longer for those whose VS6010 mL (mean 90.9 months vs 62.6 months; P<.001) and VS455 mL (mean 91.9 months vs 65.2 months; PZ.001). Similarly, multivariable analyses revealed that VS60 (PZ.001) and VS45 (PZ.003) were significant predictors of clinical hypothyroidism. The freedom from clinical hypothyroidism was longer for those whose VS6010 mL (91.5 months vs 73.3 months, PZ.002) and VS455 mL (91.5 months vs 75.9 months, PZ.007). Receiver-operating characteristics (ROC) analyses revealed that the areaunder-the-curve (AUC) value for VS60 was significantly higher than that for VS45 for both biochemical (0.751 vs 0.660; PZ.009) and clinical hypothyroidism (0.718 vs 0.607; PZ.007), respectively. Conclusion: VS60 and VS45 of the thyroid significantly predicted postIMRT hypothyroidism and should be considered important priorities of dose constraints during IMRT optimisation for NPC. Author Disclosure: V.H. Lee: None. A.S. Chan: None. C. Choi: None. D.L. Kwong: None. K. Lam: None. C. Tong: None. H.C. Sze: None. S.C. Ng: None. T. Leung: None.
205 Clinical Presentation of Oropharyngeal Squamous Cell Carcinoma in the Modern Era: Does Risk Stratification Using Human Papillomavirus and Smoking Status Matter? M.J. Amsbaugh,1 M.B. Yusuf,2 E. Cash,1 C.L. Silverman,1 J. Bumpous,1 C.A. Perez,1 R. Bert,1 R. Redman,1 and N.E. Dunlap1; 1University of Louisville, Louisville, KY, 2University of Louisville School of Medicine, Louisville, KY Purpose/Objective(s): Patterns of cervical lymph node metastases (LNMs) in patients with oropharyngeal squamous cell carcinoma (OPSCC) have historically been described. Here we compare the distribution of cervical LNMs in the human papillomavirus (HPV) era to historical controls. We also evaluated the influence of HPV and smoking status on the clinical presentation of OPSCC. Materials/Methods: All patients with OPSCC presenting to our institutional multidisciplinary clinic from January 2010 to June 2015 were reviewed from a prospective database. Subsite, stage, smoking status, and involved anatomical nodal levels were tabulated. Variance in clinical presentation was examined using X2, Kruskal-Wallis, Mann-Whitney, and logistic regression analyses. Results: Of 291 patients, HPV/p16 status was available for 243. Preliminary analyses confirmed that patients could be grouped based on anatomical site (Group 1: tonsil, base of tongue [BOT], vallecula, nZ217; Group 2: pharyngeal wall, palate, and other nZ26) and risk level (low risk: HPV/p16 positive and 10 pack-year history of smoking, nZ78; intermediate risk: HPV/p16 positive and >10 pack-year history of smoking, nZ82; and high risk: HPV/p16 negative, nZ80). Overall, 188 patients (77.3%) had at least 1 cervical LNM at time of presentation (99.4% ipsilateral, 16.5% contralateral). Locally advanced tumor stages were uncommon at presentation (22.2% T1, 37.0% T2, 26.7% T3, 10.7% T4a, and 2.5% T4b); however, advanced nodal disease was more common (22.6% N0, 14.8% N1, 7.0% N2a, 39.1% N2b, 11.9% N2c, and 4.5% N3). Patients who were current smokers were more likely to present with metastases to level IIa than were nonsmokers (odds ratio [OR]Z4.56, PZ.032). Rates of HPV/p16 positivity (P<.001), never having smoked (PZ.016), and cervical LNM (PZ.023) were significantly higher for patients in Group 1. Low-risk Group 1 patients presented with nodal stage N2a at a much higher than expected frequency (PZ.007), and high-risk patients presented with tumor stage T4 at a much higher than expected frequency (PZ.003). Previous smokers with a BOT subsite were more likely to have clinically positive ipsilateral necks than nonsmokers (ORZ1.8, PZ.038). There were no significant differences in T stage or N stage based on HPV/p16 positivity or smoking (P>.05). Furthermore, distribution of cervical LNMs was not associated with HPV/ p16 positivity, risk group, or anatomical group (P>.05). When data were compared to historical series, no significant differences were seen in the patterns of cervical lymph node metastases for patients with OPSCC. Conclusion: HPV/p16 positivity, smoking status, risk group, and anatomical group influenced the clinical presentation of patients with OPSCC. Historical series describing the patterns of cervical LNMs in patients with OPSCC remain clinically relevant. Author Disclosure: M.J. Amsbaugh: Employee; University of Louiville. M.B. Yusuf: None. E. Cash: None. C.L. Silverman: None. J. Bumpous: None. C.A. Perez: Employee; University of Louiville. R. Bert: None. R. Redman: None. N.E. Dunlap: Honoraria; Osler.
206 Demographics, Disparities, and Survival in Young Patients With Oral Cavity Squamous Cell Carcinoma: A Population-Level Analysis of 3828 Cases K. Zhan, E.A. Nicolli, and T. Day; Medical University of South Carolina, Charleston, SC Purpose/Objective(s): To characterize and identify prognosticators in oral cavity squamous cell carcinomas (OCSCC) in young patients. To determine whether type of hospital and insurance status correlates with survival. Materials/Methods: We conducted a retrospective review of the National Cancer Data Base from 1998 to 2012 of OCSCC in patients younger than