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International Journal of Radiation Oncology Biology Physics
and RI (P Z 0.17 in ALL; P Z 0.61 in AML). In multivariate analyses TBI fractionation was not found as independent prognostic factor neither in ALL nor in AML patients for LFS, OS, RI and NRM. Conclusion: The SARASIN study showed that 12 Gy-TBI dose delivered either in 2 fractions per day following 3 days or in one fraction per day following 2 or 3 days prior allogeneic transplantation resulted in similar RI and survival, in both ALL and AML patients. Furthermore, the reduction of the number of fractions even in this rather high TBI dose level is not associated with increased risk of NRM. Altogether, our data suggests that 12 Gy could be delivered safely in less than 6 fractions. Our findings are not only of considerable practical importance for radiotherapy departments but moreover it may lead to increase TBI availability as pre allogeneic transplantation conditioning regimen for acute leukemia. Author Disclosure: Y. Belkacemi: None. M. Labopin: None. G. Sebastian: None. G.K. Loganadane: None. L. Miszyk: None. M. Michallet: None. G. Socie: None. N.P. Schaap: None. C.J. Jan: None. I.Y. Agha: None. M. Mohty: None. A. Nagler: None.
treatment volume, and administered chemotherapy regimens. We attempted to minimize the effect of these limitations by choosing a contemporary cohort of patients. These results support a cautionary approach towards the omission of RT in stage III HL patients. Further prospective evaluation of the role of RT in stage III HL patients is warranted. Author Disclosure: J.E. Bates: None. S. Dhakal: None. A. Mazloom: None. C. Casulo: None. L.S. Constine: None.
1019 The Role of Radiation Therapy in Patients with Stage III Classical Hodgkin Lymphoma: A Propensity Score Matched Analysis of the Surveillance, Epidemiology, and End Results Database J.E. Bates,1 S. Dhakal,2 A. Mazloom,3 C. Casulo,4 and L.S. Constine2; 1 Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL, 2Department of Radiation Oncology, University of Rochester Medical Center, Rochester, NY, 3Tacoma Valley Radiation Oncology, Tacoma, WA, 4Department of Medical Oncology, University of Rochester Medical Center, Rochester, NY Purpose/Objective(s): The role of radiotherapy (RT) in the management of patients with stage III Hodgkin lymphoma (HL) is controversial. Prospective, randomized evidence and retrospective studies fail to clearly define efficacy/morbidity for this group since they include a heterogeneous population of “advanced stage” patients, with both stage III and stage IV disease. We theorize that differences in disease distribution and burden, as well as overall survival (OS), between these two stages may obfuscate the benefit of RT in patients with stage III disease. We aimed to investigate our theory in a population-based cohort from a very contemporary time period to minimize the effect of changing patterns of chemotherapy. Materials/Methods: We queried the Surveillance, Epidemiology, and End Results (SEER) database for patients with stage III HL diagnosed between 2004 and 2012 and at least 20 years of age. In addition to standard KaplanMeier and Cox proportional hazards analyses for several variables, we performed a propensity score matched analysis (PSMA) for the effect of RT on both OS and cause-specific survival (CSS). Propensity scores were calculated based on race, gender, age, histologic subtype, presence of B symptoms, and presence of extranodal disease. Results: A total of 3,600 patients were identified; 1,224 were included in the PSMA. The median follow-up was 34 months. In the unmatched analysis, age greater than 65 years was associated with worse OS (hazard ratio (HR), 5.31; 95% confidence interval (CI), 4.61 e 6.11; P < 0.001). The presence of B symptoms (data available in 3,185 patients) was associated with diminished OS (HR, 1.33; 95% CI, 1.14 e 1.56; P < 0.001). The receipt of RT was associated with improved OS (HR, 0.45; 95% CI, 0.35 e 0.59; P < 0.001; 5-year OS, 87.5% vs 69.6%). The statistical significance of these associations was identical on analysis for CSS. The association between RT and improved OS held on PSMA (HR, 0.70; 95% CI, 0.51 e 0.95; P Z 0.02). This association was not statistically significant in analysis for CSS on PSMA (HR, 0.66; 95% CI, 0.42 e 1.02; P Z 0.06). Conclusion: In this large population-based hypothesis-generating analysis, we show that the receipt of RT is associated with improved OS in patients with stage III HL on both unmatched analysis and PSMA. We additionally show an association between RT and improved CSS on unmatched analysis, but not PSMA. These conclusions are limited by those limitations inherent in the SEER database, including lack of information on RT dose,
1020 Treatment Outcome of Extended Involved-Field Intensity Modulated Radiation Therapy for Early Stage Extranodal Nasal-Type NK/T-Cell Lymphoma in the Era of Modern Chemotherapy T. Wu1 and Y.X. Li2; 1Affiliated Hospital of Guizhou Medical University Guizhou Cancer Hospital, Guiyang, China, 2Radiation Oncology Department, National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing, China Purpose/Objective(s): This study aimed to evaluate the role of extended involved-field intensity modulated radiation therapy (IMRT) for patients with early stage extranodal nasal-type NK/T-cell lymphoma (NKTCL) who received new regimens chemotherapy. Materials/Methods: Between 2007 and 2016, 165 patients with early stage NKTCL underwent definitive high-dose and extended involved-field IMRT with (n Z 158, 95.8%) or without chemotherapy (n Z 7, 4.2%). One hundred forty patients (84.8%) received radiation dose more than 50 Gy to the primary tumor, whereas only 25 patients (15.2%) received less than 50 Gy. The majority of patients (n Z 157, 89.1%) were treated with Lasparaginaseebased regimens CT,whereas only 11 (6.7%) patients with doxorubicin-based CHOP/CHOP-like regimens. One hundred and nine patients (66.1%) received more than four cycles of chemotherapy. The locoregional control (LRC), overall survival (OS), and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Results: The 5-year OS, LRC, and PFS of all patients were 74.2%, 84.4%, and 72.5%. Patients who received 50 Gy had significantly higher LRC than those with <50 Gy, with 5-year LRC of 91.8% and 39.7% (P<0.001). The 5-year OS for patients without any risk factors (age >60, Elevated LDH, ECOG 2, primary tumor invasion [PTI] and stage II disease, defined as low-risk group) were 94.2%, whereas it was only 68.1% (P Z 0.002) for patients with any risk factors (high-risk group). For high-risk early stage group, patients who received more than 4 cycles of chemotherapy significantly improved outcomes. The 5-year OS and PFS rates were 71.3% and 70.4% for patients with 4 cycles chemotherapy, compared with 59.5% (P Z 0.032) and 54.4% (P Z 0.009) for those with <4 cycles chemotherapy respectively. In multivariate analysis, ECOG 2, PTI, and Ann Arbor stage II were associated with poor OS. ECOG 2 and PTI were associated with increased risk of locoregional recurrence; whereas ECOG 2, PTI, primary site outside nasal cavity were associated with increased risk of PFS. Conclusion: In the modern era of IMRT and L-asparaginaseebased chemotherapy, High-dose and extended-involved field IMRT for patients with early stage NKTCL achieved favorable outcomes. High-risk early stage patients who received more than 4 cycles chemotherapy had significantly improved OS and PFS. Author Disclosure: T. Wu: None. Y. Li: Employee; Cancer Hospital & Institute, CAMS & PUMC; Cancer Hospital & Institute, CAMS & PUMC.
1021 Patterns of Failure Analysis of Patients With Double Hit or Double Expressor Lymphomas: Implications for Radiation Therapy L. Trivedi,1 V. Tumati,1 J. Li,1 P. Patel,1 M. Vusirikala,1 N. Sadeghi,1 S. Rizvi,1 W. Chen,1 J. Wachsmann,1 P. Scaglioni,1 R. Collins,1 and N.B. Desai2; 1University of Texas Southwestern Medical Center, Dallas, TX, 2Department of Radiation Oncology, University of Texas at Southwestern Medical Center, Dallas, TX