T2 weighted MRI in assessment of volume changes during radiotherapy of high grade gliomas.

AIM To determine whether any changes in gross tumor volume occur between pre treatment MRI and week 5 MRI in high grade gliomas treated by conformal radiotherapy. METHODS AND MATERIALS Between July 2003-July 2005, 17 patients with WHO grades 3 and 4 malignant gliomas treated with conformal radiotherapy to a total dose of 60 Gy were included in this retrospective study. All patients had undergone T2 weighted MRI a day before treatment and then again at end of week 5 of treatment for definition of initial and boost fields respectively. Gross tumor volumes were delineated on the two MRI's of each patient and the differences were noted. Two patients with multifocal disease were excluded from the final analysis. RESULTS Of the 15 patients with unifocal disease, 12/15 cases (80%) showed a reduction in tumor volumes (median 54.85 cc). Of these, 4/15 (26.6%) cases (two each of grade 3 and grade 4 gliomas) had an objective reduction in GTV (> or = 50%) and 3/15 (20%) cases (two of grade 4 and one of grade 3 gliomas) demonstrated an increase in tumor volume (median 14 cc). CONCLUSIONS This study has shown that a change in gross tumor volume occurred in almost all patients on week 5 MRI. The likelihood of treatment success would appear to be decreased if the tumour is not within the treatment field and hence it may be worthwhile to do a mid treatment MRI for definition of boost volumes especially in dose escalation trials employing highly conformal radiotherapy fields.

[1]  T. Chenevert,et al.  Evaluating changes in tumor volume using magnetic resonance imaging during the course of radiotherapy treatment of high-grade gliomas: Implications for conformal dose-escalation studies. , 2005, International journal of radiation oncology, biology, physics.

[2]  M. Mehta,et al.  The Impact of Mid-Treatment MRI on Defining Boost Volumes in the Radiation Treatment of Glioblastoma Multiforme , 2004, Technology in cancer research & treatment.

[3]  S. Spencer,et al.  Role of Radiation Therapy and Radiosurgery in Glioblastoma Multiforme , 2003, Cancer journal.

[4]  U Oppitz,et al.  3D-recurrence-patterns of glioblastomas after CT-planned postoperative irradiation. , 1999, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[5]  D. Nelson,et al.  Recursive partitioning analysis of prognostic factors in three Radiation Therapy Oncology Group malignant glioma trials. , 1993, Journal of the National Cancer Institute.

[6]  N. Bleehen,et al.  A Medical Research Council trial of two radiotherapy doses in the treatment of grades 3 and 4 astrocytoma. The Medical Research Council Brain Tumour Working Party. , 1991, British Journal of Cancer.

[7]  W. Dillon.  Imaging of central nervous system tumors. , 1991, Current opinion in radiology.

[8]  K. Wallner,et al.  Patterns of failure following treatment for glioblastoma multiforme and anaplastic astrocytoma. , 1989, International journal of radiation oncology, biology, physics.

[9]  Fred H. Hochberg,et al.  Assumptions in the radiotherapy of glioblastoma , 1980, Neurology.

[10]  W. Simpson,et al.  Fractionation study in the treatment of glioblastoma multiforme. , 1976, International journal of radiation oncology, biology, physics.

[11]  M. Bernstein,et al.  Randomized study of brachytherapy in the initial management of patients with malignant astrocytoma. , 1998, International journal of radiation oncology, biology, physics.

[12]  M. Prados,et al.  Patterns of recurrence of glioblastoma multiforme after external irradiation followed by implant boost. , 1994, International journal of radiation oncology, biology, physics.

[13]  Srinivasan Vijayakumar,et al.  Quantitation of treatment volumes from CT and MRI in high-grade gliomas: implications for radiotherapy. , 1992, Magnetic resonance imaging.

[14]  D F Nelson,et al.  Combined modality approach to treatment of malignant gliomas--re-evaluation of RTOG 7401/ECOG 1374 with long-term follow-up: a joint study of the Radiation Therapy Oncology Group and the Eastern Cooperative Oncology Group. , 1988, NCI monographs : a publication of the National Cancer Institute.