Proceedings of the 52nd Annual ASTRO Meeting S555

Conclusions: IMRT decreases dramatically the highest doses delivered into the breasts for female patients treated for Hodgkin’slymphoma, however a long follow-up is necessary to translate this decreasing in lower secondary cancers incidence.

Author Disclosure: D.N. Antoni, None; P. Meyer, None; S. Ame, None; C. Niederst, None; K. Bourahla, None; D. Karamanou-kian, None; G. Noel, None.

2785 Prognosis Comparison and Therapeutic Considerations between Primary Nasopharyngeal B- and T/

NK-cell Non-Hodgkin’s Lymphomas at Early Stage: A Study of 136 Cases in South China

Y. Zhang1,2, J. S. Li3, Y. Yang1,2, G. R. Zou3, F. Y. Xie1,2, H. Y. Wang1,2, Y. F. Xia1,2

1State Key Laboratory of Oncology in Southern China, Guangzhou, China, 2Department of Radiation Oncology, Sun Yat-senUniversity Cancer Center, Guangzhou, China, 3Department of Clinical Oncology, Panyu People’s Hospital, Guangzhou, China

Purpose/Objective(s): Primary nasopharyngeal non-Hodgkin’s lymphoma (PNL) is relatively common in China, and the treat-ment outcome seems different between various NHL phenotypes. This study was to investigate the clinical features and prognosesof B-cell and T/NK-cell PNL at early stage, so to provide evidences for treatment strategies optimization.

Materials/Methods: Clinical data of patients with newly diagnosed early stage PNL, admitted from Oct 1990 to Jul 2009, wereretrospectively reviewed. Pathology was reviewed according to 2008 WHO classification and cases with diagnoses of highly ag-gressive NHL were excluded. 136 patients composed of 67 with diffused large B-cell lymphoma (DLBCL) and 12 with indolenttype B NHL (both in B group), and 57 with T- or natural killer (NK)-cell NHL (T group), were included in this study. There were 89male and 47 female, aged 12 to 82 years (median 50). Ann Arbor stages at diagnoses were stage I in 54 patients and stage II in therest. 76 patients received chemotherapy (CT) followed by radiotherapy (RT), 49 patients received CT alone, and 11 patients re-ceived RT alone. CT was mostly in CHOP regimen for median 5 cycles. Megavoltage photon / electron beams were used in con-ventional fractionated RT to total dose of 26-70Gy (median 52Gy). Treatment patterns in the two groups were similar, but therewere more stage II disease in B group patients.

Results: Median follow-up duration for survived patients was 39.4 months. For patients with DLBCL, indolent B-cell NHL, and T/NK-cell NHL, 5-year overall survival (OS) rates were 56.3%, 87.5%, and 48.4% (p = 0.056); 5-year progress-free survival (PFS)rates were 45.3%, 69.3%, and 34.2% (p = 0.019); and 5-year local control (LC) rates were 76.3%, 100.0%, and 56.1% (p\0.001),respectively. Compared with those in B group, T group patients manifested more often of B symptoms, more elevated LDH, andmore ratio of younger than 60-years old at diagnoses. Patients in B group achieved higher CR rate (56.9% vs. 30.2%, p = 0.005)than those in T group after initial CT. In T group, patients who received both CT and RT showed a superior complete remission rate(20.0% vs. 84.4%, p = 0.005), 5-year PFS rate (0.0% vs. 45.5%, p \ 0.001), and 5-year OS rate (20.0% vs. 59.6%, p \ 0.001),compared with those received CT alone. In contrast, the addition of RT to CT seemed to provide little benefit to 5-year PFS (56.7%vs. 56.4%, p = 0.775) or 5-year OS (59.2% vs. 64.0%, p = 0.577) for patients in B group.

Conclusions: Among patients with early stage PNL, T/NK-cell phenotype means worse prognoses compared with B-cell pheno-type. RT or chemoradiotherapy should be more emphasized in patients with T/NK-cell phenotype, who achieve not nearly far fromsatisfying results with CT alone.

Author Disclosure: Y. Zhang, None; J.S. Li, None; Y. Yang, None; G.R. Zou, None; F.Y. Xie, None; H.Y. Wang, None; Y.F. Xia,None.

2786 Positron Emission Tomography for Response Assessment of Lymphoma Patients Having Residual

Abnormalities following Initial Treatment: The Impact on Clinical Management

M. Bernard, R. W. Tsang, L. W. Le, D. C. Hodgson, J. Kuruvilla, V. Kukreti, A. Sun, W. Wells, M. Crump, M. K. Gospodarowicz

Princess Margaret Hospital, University of Toronto, ON, Canada

Purpose/Objective(s): Management of residual abnormalities post-treatment in lymphoma is often difficult. 18F-positron emissiontomography (PET) appears to be especially suitable to differentiate active lymphoma and inactive scar tissue. Between 2007 and2009, we prospectively studied patients with unconfirmed complete response (CRu) or partial response (PR) with PET and assessedits impact on the management.

Materials/Methods: Sixty-nine patients (26HL/43 NHL) who had CRu (n = 22) and PR (n = 47) after definitive treatment wereprospectively entered in an IRB-approved study. Early stage patients (pts) planned for combined-modality therapy, with CRu or PRafter chemotherapy (CT), were also eligible (n = 26). Thirty-three pts had stage I-II and 36 stage III-IV. PET results were reportedaccording to the International Harmonization Project. The study did not mandate biopsy for PET+ cases. The responsible oncol-ogist was surveyed on the proposed management without PET, and again 4 weeks after PET.

Results: Thirty-nine of 69 pts had a positive PET scan (57%). Post treatment PET was +ve in 9/22 pts with CRu (41%) and 30/47 pts with PR (64%). A biopsy was done in 13/39 PET+ pts: residual lymphoma in 7 and GIST tumor in 1 pt; no residualtumor in 5 pts. Overall, PET scan results have change clinical management in 52% (n = 36, 5CRu/31PR). Among these, treat-ment intensification was seen in 20 pts (56%): salvage CT + ASCT intent in 11 pts, addition/increase of RT dose in 7 pts, moreCT in 1 pt and gastrectomy for 1 pt. For 9 pts (25%), the management was less intense, essentially with observation post PETresults. Other alternate management strategies not classifiable into these 2 groups were used in 7 pts (19%). After a medianfollow-up of 21.4 months (range, 6.2-45.8), treatment failure rate (relapse/persistent disease) in PET+ pts was 30% (11/37, 2pts not evaluable). PET+ pts had worse disease free survival (DFS) than PET- pts, with 2-yrs DFS rate of 73% versus93%(p = 0.01), respectively.

Conclusions: PET scan done for the evaluation of post-treatment residual abnormalities significantly impacted clinical manage-ment in 52% of patients. Although the study was not designed to assess the impact on outcome, with short follow-up, PET+ patientsstill fared less well than PET- patients, despite the management modification post PET results.

Author Disclosure: M. Bernard, None; R.W. Tsang, None; L.W. Le, None; D.C. Hodgson, None; J. Kuruvilla, None; V. Kukreti,None; A. Sun, None; W. Wells, None; M. Crump, None; M.K. Gospodarowicz, None.