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Purpose Although the usefulness of O6-methylguanine DNA methyltransferase (MGMT) promoter methylation analysis for predicting response to chemoradiotherapy and the prognosis of patients with glioblastoma has been widely reported, there is still no consensus regarding how to define MGMT promoter methylation percentage (MGMTpm%) cutoffs by pyrosequencing method. The aim of this study was to determine the optimal cutoff value of MGMT promoter methylation status using volumetric analysis focused on the tumor volume ratio (TVR) measured by MRI. Methods This retrospective study included newly diagnosed IDH wild-type glioblastoma patients with residual tumor after surgery, followed by local radiotherapy with temozolomide. TVR was defined as the tumor volume at 6 months after the initial chemoradiotherapy administration divided by the tumor volume before the start of therapy. The mean MGMTpm% of 16 CpG islands (74–89) was analyzed using pyrosequencing. We statistically analyzed the correlation between MGMTpm%, TVR, and change in Karnofsky performance status. Results The study included 44 patients with residual tumors. Thirteen (92.9%) of 14 patients with MGMTpm% ≥ 23.9% showed 50% or more volumetric response, leading to prolonged survival, and 17 (70.8%) of 24 patients with MGMTpm% Conclusion Evaluation of MGMTpm% by pyrosequencing is important in predicting the volumetric response and prognosis of glioblastoma patients with residual tumors.

A highly enhanced cap attached to the surface of metastatic tumors in the brain parenchyma is occasionally encountered on magnetic resonance (MR) images. This atypical enhanced cap tends to occur in severe peritumoral edema and may produce the characteristic bulge of a metastatic mass lesion termed the "comet tail sign" (CTS). The purpose of this study was to demonstrate the features of the CTS using MR imaging and pathological findings, and to clarify its clinical relevance. We selected 21 consecutive cases of newly diagnosed metastases from MR imaging studies that demonstrated the CTS; all had diffuse peritumoral edema. The MR T2-weighted images showed similarly homogenous and high intensity signals in both the tail and peritumoral edema. Fourteen of the 21 patients underwent surgical resection of their tumors, and 12 tails were separately removed for pathological examination, no tumor cells which revealed. We speculate that the CTS does not contain neoplastic tissues but is observed as a result of the leakage of contrast medium from the tumor body into the interstitial space of the white matter. Although CTS is a peculiar and uncommon enhancement pattern, it has clinical significance in determining the extent of the margin for invasive local treatments, such as surgical resection or stereotactic radiotherapy; this is particularly true in and near the eloquent areas.

Purpose This study explored the superiority of temozolomide (TMZ) + interferonβ (IFNβ) to standard TMZ as treatment for newly diagnosed glioblastoma (GBM) via randomized phase II screening design. Experimental design Eligibility criteria included histologically proven GBM, with 50% of the tumor located in supratentorial areas, without involvement of the optic, olfactory nerves, and pituitary gland and without multiple lesions and dissemination. Patients in the TMZ + radiotherapy (RT) arm received RT (2.0 Gy/fr/day, 30 fr) with TMZ (75 mg/m2, daily) followed by TMZ maintenance (100–200 mg/m2/day, days 1–5, every 4 weeks) for 2 years. Patients in the TMZ + IFNβ + RT arm intravenously received IFNβ (3 MU/body, alternative days during RT and day 1, every 4 weeks during maintenance period) and TMZ + RT. The primary endpoint was overall survival (OS). The planned sample size was 120 (one-sided alpha 0.2; power 0.8). Results Between Apr 2010 and Jan 2012, 122 patients were randomized. The median OS with TMZ + RT and TMZ + IFNβ + RT was 20.3 and 24.0 months (HR 1.00, 95% CI 0.65–1.55; one-sided log rank P = 0.51). The median progression-free survival times were 10.1 and 8.5 months (HR 1.25, 95% CI 0.85–1.84). The incidence of neutropenia with the TMZ + RT and the TMZ + IFNβ + RT (grade 3–4, CTCAE version 3.0) was 12.7 versus 20.7% during concomitant period and was 3.6 versus 9.3% during maintenance period. The incidence of lymphopenia was 54.0 versus 63.8% and 34.5 versus 41.9%. Conclusions TMZ + IFNβ + RT is not considered as a candidate for the following phase III trial, and TMZ + RT remained to be a most promising treatment. This trial was registered with the UMIN Clinical Trials Registry: UMIN000003466.