Comparison Of Long-term Survival Between Temozolomide-based Chemoradiotherapy And Radiotherapy Alone For Patients With Low-grade Gliomas After Surgical Resection

Purpose: This study was designed to compare the survival outcomes of temozolomide-based chemoradiotherapy(TMZ + RT)vs radiotherapy alone(RT-alone)for low-grade gliomas(LGGs)after surgical resection.Patients and methods: In this retrospective analysis,we reviewed postoperative records of 69 patients with LGGs treated with TMZ + RT(n=31)and RT-alone(n=38)at the Shandong Cancer Hospital Affliated to Shandong University between June 2011 and December 2013.Patients in the TMZ + RT group were administered 50–100 mg/ ㎡ oral TMZ every day until the radiotherapy regimen was completed.RT was performed 2–4 weeks after surgery when the skin incision had almost healed.Patients were fixed with a thermal head mold and positioned under a computed tomography simulator.Radiation was delivered using a Varian linear accelerator.The gross tumor volume was targeted on the contrast-enhanced residual tumor and/or surgical residual cavity of postoperative T2-weighted magnetic resonance imaging.The planning target volume was more than 1-2 cm margin to the dose of 50 Gy,and then the expanded margin was shrunk to 0.8-1 cm with a total dose ranging from 50 to 66 Gy in daily 2 Gy fractions by three-dimensional conformal radiation therapy.Symptoms of cerebral edema(such as headache,dizziness,or nausea)could be relieved after the use of relative drugs.Results: In the group of 31 patients with chemoradiotherapy,only 2 cases had mild gastrointestinal reaction and no cases had obvious bone marrow suppression.Furthermore,there were no cases stopping taking drug for the reason of other intolerable side effects.The median follow-up since surgery was 33 months and showed no signifcant intergroup differences(P=0.06).There were statistically signifcant intergroup differences in the progression-free survival rate(P=0.037),with 83.9% for TMZ-RT group and 60.5% for RT-alone group.The overall 2-year overall survival(OS)rate was 89.86%.Age distribution(≥45 years and < 45 years)and resection margin(complete resection or not)were significantly associated with OS(P=0.03 and P=0.004,respectively).Conclusion: Although no differences were found in the 2-year OS between the TMZ +RT and RT-alone groups,there was a trend toward increased 2-year progression-free survivalin the TMZ + RT group.With better tolerability,concurrent TMZ chemoradiotherapy may be beneficial for postoperative patients with LGGs.Age distribution and surgical margin are likely potential indicators of disease prognosis.The possible differences in long-term survival between the two groups and the links between prognostic factors and long-term survival may be worthy of further investigation.