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Correlation of conventional magnetic resonance imaging features with O6-methylguanine-DNA-methyltransferase gene promoter methylation status and survival outcomes in patients with newly diagnosed glioblastoma: Single-center correlative imaging substudy from a prospective clinical trial
Tejpal Gupta1, Anil Tibdewal1, Sarthak Mohanty1, Torsten Pietsch2, Sadhana Kannan3, Shashikant Juvekar4, Nikhil Merchant4, Sridhar Epari5, Aliasgar Moiyadi6, Prakash Shetty6, Goda Jayant Sastri1, Rakesh Jalali1
1 Department of Radiation Oncology, ACTREC/TMH, Tata Memorial Centre, Mumbai, Maharashtra, India
2 Department of Neuro-Pathology, University of Bonn, Bonn, Germany
3 Department of Clinical Research Secretariat, ACTREC/TMH, Tata Memorial Centre, Mumbai, Maharashtra, India
4 Department of Radio-Diagnosis, ACTREC/TMH, Tata Memorial Centre, Mumbai, Maharashtra, India
5 Department of Pathology, ACTREC/TMH, Tata Memorial Centre, Mumbai, Maharashtra, India
6 Division of Neurosurgery, Department of Surgical Oncology, ACTREC/TMH, Tata Memorial Centre, Mumbai, Maharashtra, India
Correspondence Address:
Dr. Tejpal Gupta
Department of Radiation Oncology, Neuro-Oncology Disease Management Group, ACTREC, Tata Memorial Centre, Kharghar, Navi Mumbai - 410 210, Maharashtra
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/glioma.glioma_12_18
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Background: Imaging features may be reflective of inherent disease biology and serve as potentially useful biomarkers in primary brain tumors. This study aimed to correlate conventional magnetic resonance imaging (MRI) features with O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status and survival in glioblastoma. Methods: Conventional semantic imaging features were systematically extracted from preoperative MRI of 34 patients with glioblastoma by two reviewers independently and correlated with MGMT methylation status and survival using appropriate statistical tests. Results: MGMT promoter was methylated in 10 (30%) patients, unmethylated in 15 (44%) patients, and invalid or uninterpretable in 9 (26%) patients. Four imaging features, such as border, edema, contact with subventricular zone (SVZ), and necrosis, showed borderline correlation with methylation status. On multivariate logistic regression analysis, the odds of having methylated tumor were significantly reduced for tumors in contact with SVZ and borderline reduced for tumors with sharp borders. With a median follow-up of 18 months (interquartile range, 13–33 months), the median progression-free survival (PFS) and overall survival (OS) were 12.1 months (95% confidence interval [CI]: 9.9–14.3 months) and 17.1 months (95% CI: 12.6–21.5 months), respectively, for the study cohort. Among the semantic imaging features extracted from conventional MRI, only perilesional edema correlated significantly with PFS as well as OS. The hazards of both progression and death were significantly increased for tumors with moderate-to-severe edema on Cox regression analysis. Conclusion: Contact with SVZ and sharp tumor borders shows weak negative correlation with MGMT promoter methylation status in glioblastoma. Among all MRI features investigated in this work, moderate-to-severe edema is the only imaging feature that independently correlates with significantly inferior survival.
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