Head and Neck Cancer
PV QA 2 - Poster Viewing Q&A 2
Purpose/Objective(s): To evaluate the efficacy and toxicity using different doses per fraction in patients treated with IMRT for NPC
Materials/Methods: We reviewed 140 patients with stage II-IVb NPC treated with chemotherapy and IMRT from January 2012 to December 2016 at Ruijin Hospital of Shanghai Jiaotong University. All patients treated with IMRT using three kinds of dose fraction: 2.0 Gy per fraction, 2.12 Gy per fraction and 2.2 Gy per fraction. Radiotherapy alone or concurrent chemotherapy +/− induction chemotherapy was recommended to patients at discretion of the attending physician.
Results: There were as following: stage II in 25.7%, III in 40.7%, IVA in 19.3%, stage IVB in 14.3%. A total of 35 patients treated by dose per fraction of 2 Gy (25%), 75 patients using by 2.12Gy (53.6%) and 27 patients by 2.2Gy (19.3%) respectively. In total, 121 patients（86.4%） received induced chemotherapy, 102 received concurrent chemotherapy（72.9%）, and 42 patients（30%）received adjuvant chemotherapy after IMRT. The median follow-up time for the entire group was 33.2 months (range 6.2 to 67.3 months). A total of 8 cases (5.7%) experienced neck recurrence 5 developed local recurrence in the primary area (3.6%). Eighteen patients developed distant metastases (12.9%). Twenty patients are dead (8.7%). The 3-year OS rate of whole cohort was 75.6%, and the 3-year L-FFR, D-FFR, and DFS rates were 88.4%, 75.6%, and 70.1%, respectively. On univariate analysis, T stage, N stage, Tumor Volume, positive node volume and altered dose per fraction were significant prognostic factors for OS. On multivariate analyses, altered dose per fraction was the only independent risk factor for OS (p=0.007; HR=3.6(1.4~9.0), D-FFR(p=0.048；HR=2.1（1.1~4.3) and DFS（p=0.005；HR=2.3（1.3~4.1). The OS of patients treated with IMRT using altered per fraction by 2Gy, 2,12Gy, 2.2Gy was 57.6%,78.9% and 100% respectively. All patients experienced mild to moderate radiation-induced adverse-effects. The most common acute toxicity was mucositis. During RT, 102(72.8%) patients experienced acute grade 3-4 mucositis. The incidence of mucositis among the group of altered per fraction presented no difference. The second most common acute grade 3-4 toxicity was cytopenia (15/140，10.7%), mostly was leukopenia/neutropenia. Only one patient experienced serious late toxicities and infected encephalitis.
Conclusion: In our data, a higher dose per fraction contributed to a better prognosis in terms of reduction of recurrence rate and overall survival. The toxicity was acceptable and had no difference among altered per fraction group. Prospective and larger series are needed to confirm these findings.
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