Management of patients with recurrent glioblastoma using hypofractionated stereotactic radiotherapy.

BACKGROUND: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The chance of cure is very limited due to treatment-refractory disease course with frequent recurrences despite aggressive multimodality management. In this retrospective study, we evaluated treatment outcomes of hypofractionated stereotactic radiotherapy (HFSRT) in the management of recurrent GBM and report our single-center experience. METHODS: Twenty-eight patients receiving HFSRT for recurrent GBM between September 2008 and February 2014 were retrospectively assessed. Total radiotherapy dose was 25 Gy delivered in 5 fractions over 5 consecutive days for all patients. High-precision, image-guided volumetric modulated arc therapy was delivered with a linear accelerator using 6-MV photons using the frameless technique. Analyzed prognostic factors were age, gender, Karnofsky performance status (KPS), tumor location, planning target volume (PTV) size, overall survival (OS), progression-free survival (PFS), time interval between completion of treatment with Stupp protocol at primary diagnosis and recurrence. RESULTS: Median follow-up time was 42 months (range 2-68). Median time interval between primary chemoradiotherapy and HFSRT was 11.2 months (range 4-57.9). Median OS and PFS calculated from reirradiation was 10.3 months and 5.8 months, respectively. Longer interval between initial treatment and recurrence (p = 0.01), smaller PTV size (p = 0.001), KPS ≥70 (p = 0.005) and younger age (p = 0.004) were associated with longer OS on statistical analysis. CONCLUSION: HFSRT offers a feasible and effective salvage treatment option for recurrent GBM management. Prognostic factors associated with longer OS in our study were longer interval between initial treatment and recurrence, smaller PTV size, KPS ≥70 and younger age.

The variability of applicator position among high dose rate intracavitary brachytherapy applications in cervical cancer patients treated with ring & tandem applicators.

OBJECTIVE: To evaluate the interindividual and intraindividual applicator position variability in high dose rate ring and tandem intracavitary brachytherapy applications in locally advanced cervical cancer. PATIENTS AND METHODS: Eight patients with locally advanced cervical cancer formed the study population. They had been treated in Dokuz Eylül University Department of Radiation Oncology between the years 2000 and 2005 with high dose rate intracavitary brachytherapy using ring and tandem applicators. The 3-dimensional geometric variation of the applicator center in craniocaudal, mediolateral and anteroposterior directions was determined on the basis of bony reference points in 24 pairs of orthogonal films obtained in the conventional simulator. Then the following evaluations were performed: 1) the applicator position variability in all applications (interindividual variability), 2) the intraindividual applicator position variability relative to the first application, 3) the intraindividual applicator position variability relative to the average of three applications. Among the potential factors that might influence the reproducibility of ring and tandem applications, age, stage, the period between external radiotherapy and brachytherapy were evaluated by univariate analysis. RESULTS: Standard deviation of interindividual applicator variability was 3.83 mm in craniocaudal, 0.39 mm in mediolateral and 2.86 mm in anteroposterior directions. The standard deviation of intraindividual variability relative to the first application was 1.91 mm in craniocaudal, 0.4 mm in mediolateral, and 4.26 mm in anteroposterior directions. The standard deviation of intraindividual variability relative to the average of three applications was 0.95 mm in craniocaudal, 1.86 mm in mediolateral, and 1.24 mm in anteroposterior directions. According to univariate analysis, no factor influenced applicator position variability. CONCLUSIONS: In order to extract definitive conclusions about factors that affect positional reproducibility of ring and tandem applicators, studies are needed that include larger numbers of patients.