Proceedings of the 52nd Annual ASTRO Meeting S547

parameters were significantly associated with PFS: MTV (p = 0.008) and iSUV (p = 0.01). Three calculated SUV parameterswere associated with OS: MTV (p = 0.005), SUVmax (p = 0.046) and iSUV (p = 0.007). IPS was associated with PFS (p = 0.03)and OS (p = 0.008).

Conclusions: Calculated PET metrics may provide predictive information beyond that of traditional clinical factors. These findingssuggest quantitative metrics as a means to identify patients at high risk of treatment failure, at a early time point when treatmentintensification could be considered and may be useful in adaptive clinical trials of HD.

Author Disclosure: D. Tseng, None; L.P. Rachakonda, None; Z. Su, None; R. Advani, None; S.A. Rosenberg, None; R.T. Hoppe,None; A. Quon, None; E.E. Graves, None; B.W. Loo, None; P.T. Tran, None, S. Horning, None.

2767 Preliminary Experience with Proton Radiotherapy in Mediastinal Lymphoma

Y. Chen, J. Adams, J. S. Abramson, E. P. Hochberg, N. J. Tarbell, T. DeLaney

Massachusetts General Hospital, Boston, MA

Purpose/Objective(s): Long-term cardiopulmonary toxicity and second malignancy risks of mediastinal radiation therapy are wellrecognized sequelae of lymphoma radiotherapy. Efforts to reduce dose to lungs, cardiac structures, spinal cord, and uninvolvedtissue are needed. We report our early single institutional experience using proton radiotherapy in patients with bulky mediastinalHodgkin’s or non-Hodgkin’s lymphoma.

Materials/Methods: Twenty patients with Hodgkin’s lymphoma (n = 16) or mediastinal DLBCL (n = 4) underwent definitive orsalvage involved field radiotherapy from 2006-2009. Indications for proton included prior mediastinal radiation (n = 2) or bulkymediastinal disease involving pericardial, hilar, and/or subcarinal nodes (n = 18). 3D conformal photon plans were generated andcompared to proton plan for target coverage, organs at risk, and integral dose. We analyzed disease control as well as acute andsubacute toxicities.

Results: Median age of patients was 30.5 years (16 to 62 years); 10 male and 10 female. In all patients, protons provided superiordosimetry compared to 3D conformal photon plans. Patients were treated with median dose of 36 GyE (proton RBE of 1 Gy pho-ton) (25.5-39.6 Gy) at 1.5 to 1.8 Gy/fraction using either a single anterior beam and/or a superior anterior beam depending on thecurvature of the anterior thorax contours. Proton plans provided an average reduction of mean lung dose reduction by 52% and V20reduction by 49%. Right coronary artery dose did not reduce significantly with protons due to proximity to precardial target vol-umes; however, left coronary artery dose significantly decreased by 30 to 90% (mean dose 12 Gy) and left ventricle dose reductionwas 72%. Mean dose to spinal cord was 8 Gy (5-30 Gy). The significant reduction in spinal cord dose with protons allowed retreat-ment in patients who had prior conventional radiotherapy. Acute side effects were limited to grade 1 or 2 anterior chest wall ra-diation dermatitis and grade 1 or 2 esophagitis in all patients, one pericarditis improved with NSAIDS, and one grade 3radiation pneumonitis which resolved with short course steroids. At median follow-up of 25.5 months, one patient relapsed dis-tantly in iliac bone and a new nodal area requiring further therapy. All 19 other patients remain without any evidence of recurrence.No severe cardiac or pulmonary toxicities have been observed so far, although long-term follow-up is necessary.

Conclusions: Proton radiotherapy appears to be a feasible and safe option in selected patients with bulky mediastinal/precardiallymphoma which can significantly reduce cardiac, lung, spinal cord, and integral dose with minimal acute/subacute toxicity andexcellent control at this preliminary time point. Additional follow-up is needed to assess long-term control and late toxicity.

Author Disclosure: Y. Chen, None; J. Adams, None; J.S. Abramson, None; E.P. Hochberg, None; N.J. Tarbell, None; T. DeLaney,None.

2768 Salvage Radiotherapy in Patients with Recurrent or Refractory CNS Lymphoma

N. Khimani1, A. K. Ng2, Y. Chen2, P. Catalano2, B. Silver2, P. M. Mauch2

1Harvard Medical School, Boston, MA, 2Dana-Farber/Brigham and Women’s Cancer Center, Boston, MA

Purpose/Objective(s): High-dose methotrexate (HD MTX) and whole-brain radiation therapy (WBRT) prolong survival in pri-mary CNS lymphoma (CNSL). However, there is limited data for the optimal management of patients with recurrent or refractoryprimary or secondary CNSL after initial MTX. This study analyzes the outcome of salvage RT for these patients.

Materials/Methods: We reviewed records of 36 patients (22 male, 14 female) with primary (n = 15) or secondary (n = 21) CNSLwho failed initial MTX therapy and received salvage RT between 1997 and 2009. Median age at CNSL diagnosis was 56 years(range, 20-83) and median time from diagnosis to start of RT was 3.3 months (range, 0.1-55.3). Included were 33 patients(92%) with diffuse large B-cell, 2 (6%) with marginal zone and 1 (3%) with mantle cell lymphoma. At diagnosis, 28 patients(78%) had brain involvement (including 1 with brain and spinal cord and 1 with brain and ocular), 4 (11%) had only spinalcord, and 4 (11%) had only leptomeningeal disease. Thirty-three patients (92%) received HD MTX with a median dose of 3.5g/m2 (range, 2.5-6.5) and the median number of cycles was 4 (range, 1-15). Three patients (8%) received only intrathecalMTX. Thirty-three patients (92%) received WBRT (median dose 40 Gy), 2 (6%) received RT to only the bilateral orbits (mediandose 36 Gy) and 1 (3%) received RT to only the spine (40 Gy). Primary endpoints were radiographic response and overall survival(OS). Variables associated with OS were determined by the log-rank test.

Results: After RT, 18 patients (50%) achieved a complete radiographic response (CR) and 6 (17%) achieved a partial response(PR), for an overall response rate of 67% [95% CI: 49%, 82%]. One patient (3%) had stable disease, 10 (28%) progressed, and1 died prior to response assessment. Of the 24 patients with a CR or PR, 10 had CNS relapse at a median of 7.9 months (range,2.8-31.9). The median OS from start of RT was 11.7 months (range, 0.6-94.7) and 47% were alive 1 year after start of RT. Medianfollow-up time among patients still alive is 43.1 months. Patients treated with\5 cycles of MTX had shorter median OS than pa-tients with $5 cycles of MTX (9.2 months vs. not reached, p = 0.04). Patients with CNSL in only the brain had longer median OSthan patients with disease in the brain and other CNS locations (16.5 vs. 4.5 months, p = 0.01). Age, gender, type of CNSL, re-sponse to MTX, and multiple CNS lesions were not associated with OS.

S548 I. J. Radiation Oncology d Biology d Physics Volume 78, Number 3, Supplement, 2010

Conclusions: Salvage RT is effective for patients with recurrent/refractory primary or secondary CNSL after initial MTX therapy,with a high response rate (67%) and a median survival of 11.7 months. Five or more cycles of MTX and CNSL limited to the brainat diagnosis are associated with longer overall survival.

Author Disclosure: N. Khimani, None; A.K. Ng, None; Y. Chen, None; P. Catalano, None; B. Silver, None; P.M. Mauch, None.

2769 Role of Radiotherapy and Prognosis Analyses in Patients with Early Stage Extranodal Nasal Type NK/

T-cell Lymphoma Treated Predominantly with Initial Chemotherapy

Y. Yang1, Y. J. Zhang1, X. B. Lin2, J. J. Wang1, S. X. Lin3, Q. Li1, Y. F. Xia1, X. X. Guan1, T. Y. Lin2

1Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, State Key Laboratory of Oncology in SouthernChina, Guangzhou 510060, China, 2Department of Medical Oncology, Cancer Center, Sun Yat-sen University, State KeyLaboratory of Oncology in Southern China, Guangzhou 510060, China, 3Department of Pathology, Cancer Center, Sun Yat-senUniversity, State Key Laboratory of Oncology in Southern China, Guangzhou 510060, China

Purpose/Objective(s): To investigate the role of radiotherapy (RT) and prognostic factors in the context of combined modalitytreatment (CMT) in outcomes of patients with stage IE-IIE extranodal nasal type NK/T-cell lymphoma.

Materials/Methods: One hundred seventy-seven patients who were diagnosed and treated in our hospital through Dec, 1990 toDec, 2006 were retrospectively analyzed, 37 of them received CT alone (median 4 cycles) and 128 received CT (median 3 cycles)followed by RT (median dose 52Gy), 6 received RT alone (median dose 58Gy) and 6 patients received RT (median 54Gy) followedby CT (median 5 cycles).

Results: Overall remission (CR+PR) rate after initial CT was 60.8% compared with 83.8% after RT (chi-square = 28.63, p \0.01). The 5-yrs overall survival (OS) rate was 46.2%, and 5-yrs progress-free survival (PFS) was 36.8%. Local control rateswere 80.9% for patients received RT (alone and with CMT) and 50.0% for those received CT alone (chi-square = 14.39, p \0.01), and 5-yrs rates of OS and PFS of them were 53.4% vs. 18.3% (chi-square = 23.38, p \ 0.01) and 45.0% vs. 10.9%(chi-square = 23.46, p \ 0.01), respectively. Compared with CT alone, the following definitive RT significantly improved thelocal control rates [83.5%, 76.2% and 50.0% (chi-square = 14.13, p \ 0.01; chi-square = 5.78, p \ 0.01)], 5-yrs rates of OS[56.2%, 48.6% and 18.3% (chi-square = 28.87, p \ 0.05; chi-square = 4.80, p = 0.03)] for patients who achieved remission ornot after initial CT.

Conclusions: RT achieves superior rates of tumor remission, local control and survival to CT, it improves outcomes in patientswho got either tumor remission or local progression after CT. Definitive RT should be reasonably the treatment of choice for earlystage extranodal nasal type NK/T-cell lymphoma.

Author Disclosure: Y. Yang, None; Y.J. Zhang, None; X.B. Lin, None; J.J. Wang, None; S.X. Lin, None; Q. Li, None; Y.F. Xia,None; X.X. Guan, None; T.Y. Lin, None.

2770 Peri-transplant Radiation Therapy for Non-Hodgkin Lymphoma

Y. Li1, Y. Chen2, A. Ng2, P. Mauch2, D. Kozono3

1Harvard Medical School, Boston, MA, 2Dana-Farber/Brigham and Women’s Cancer Center, Boston, MA, 3Harvard RadiationOncology Program, Boston, MA

Purpose/Objective(s): To determine the outcome of patients with refractory or recurrent non-Hodgkin lymphoma (NHL) treatedwith local radiation therapy (RT) before or after bone marrow/hematopoietic stem cell transplantation (HSCT) and to investigatefactors, specifically RT timing and fractionation that may influence treatment outcome.

Materials/Methods: Fifty-six patients with NHL received focal RT during a 6-month period before or after HSCT at Dana-FarberCancer Institute between 1997 and 2008. Thirty-seven patients received pre-HSCT RT and 19 received post-HSCT RT. Median RTdose was 3710 cGy (range, 1980-5510 cGy). 26 patients in the pre-HSCT RT cohort had salvage chemotherapy refractory disease,12 of whom received twice-daily RT. Patient, disease, and treatment characteristics were examined as they related to overall sur-vival (OS), disease-free survival (DFS), and time to local recurrence (LR). The Kaplan-Meier method and the log rank test wereused to analyze OS and DFS, and the cumulative incidence of local recurrence was estimated with distant recurrence considereda competing event.

Results: Median age at HSCT was 49. 21/55 (38%) had clinical stage (CS) I-II NHL and 34/55 (62%) had CS III-IV NHL at di-agnosis; 44/56 (79%) had aggressive histology (majority were diffuse large B-cell lymphoma); 10/56 (18%) had indolent histologyNHL and subsequent transformation; and 2/56 (4%) had follicular lymphoma of unknown grade. 8/56 (14%) underwent allogeneicHSCT and 48/56 (86%) underwent autologous HSCT. Median follow-up for survivors was 6.2 years. OS5 was 48%, and DFS5 was36%. The 5-year cumulative incidence of local recurrence was 38%. Median OS was 5.0 years. Twenty-four patients died ofprogressive disease, 1 died 18 days after HSCT, 2 died of GVHD, and 3 died of second malignancies (1 solid, 2 hematologic).There were 19/37 (51%) deaths in the pre-HSCT RT group and 11/19 (58%) in the post-HSCT RT group. Factors that correlatedwith decreased OS included transformed disease (p = 0.02), extranodal (p = 0.009) or bone marrow disease at diagnosis (p = 0.04),International Prognostic Index score 3-4 (p = 0.003), and allogeneic HSCT (p = 0.006). Stage, pre- vs. post-HSCT RT, and daily vs.twice daily RT did not correlate with OS, DFS or time to LR. 19/56 (34%) had in-field and 23/56 (41%) had out-of-field recur-rences; of these, 12 patients had both in- and out-of-field recurrences. Eleven of 56 (20%) experienced grade 2 early toxicityand 1 experienced grade 3 early toxicity (enteritis). Nine of 56 (16%) experienced grade 2 late toxicity and 1 experienced grade3 late toxicity (pneumonitis).

Conclusions: After adjusting for known prognostic factors, timing of peri-transplant RT and fractionation do not significantly af-fect treatment outcome. Pre-transplant RT provides effective cytoreduction in patients with salvage chemotherapy-refractory dis-ease prior to HSCT.

Author Disclosure: Y. Li, None; Y. Chen, None; A. Ng, None; P. Mauch, None; D. Kozono, None.