Author: Pallud J. et al
Source: Ann Neurol 2006;60:380-383
To determine if MRI-based measurement of growth rate prior to treatment has prognostic value in grade II gliomas.
- 143 consecutive patients diagnosed between 1992-2004
- Older than 17 years of age
- Absence of contrast enhancement
- Astrocytoma, oligodendroglioma, or mixed glioma
- At least 2 MRI studies pre-treatment, at least 3 months apart
- Patient characteristics
- Median age 34
- Symptoms at dx: 7 patients asymptomatic, 124 patients with seizures, 12 patients with headache, 7 patients with neurologic deficits
- Median tumor volume 74.5 cm 3: 54 patients had histologic diagnosis via biopsy, 34 patients had partial resections, 40 had subtotal resections, and 15 had total resections
- 92 oligodendrogliomas, 24 astrocytomas, 27 mixed histology
- Median Ki-97 proliferation index 5% (72% of cases were assessable)
- Median of 3 tumor measurements prior to treatment
- Median duration of repeat measurements was 21.7 months
- Median Individual Radiological Growth Rate (IGR) 4.4 mm/year
- Two Groups: 121 <8mm/year à low risk (LR) and 22 >8mm/year à high risk (HR)
- No significant difference between the 2 groups regarding various demographics and treatment factors except that more biopsies done in LR group
- Median clinical follow-up after radiologic diagnosis was 6.5 years
- 18.1% of LR patients died during this time versus 45.5% in HR group; median time to death was 6.7 years in LR group and 4.9 years in HR group
- Median survival was 5.16 years in HR group versus 15 years in LR group
- Univariate Analysis: inverse correlation between IGR and survival (p<0.001); histology, tumor volume, age, neurologic deficits, and Ki-67 proliferation score not significant predictors of survival
- Multivariate Analysis: IGR (p<0.0001) and tumor volume (p=0.034) were independent prognostic factors for survival
- IGR measurements prior to treatment in supratentorial grade II gliomas are predictive of prognosis
- Previous studies have shown age >40, astrocytoma histology, tumor diameter >6 cm, neurologic defects, and lesions crossing midline have worse prognosis.
- Lack of significance for several other prognostic factors may be due to small sample size.
- Limitations of histologic diagnosis
- Limited because it is "static"
- Limited to part of the tumor, particularly in biopsies or partial resections
- Conversely, tumor growth rate a macroscopic, dynamic parameter
- In tumors growing >8 mm/year, worse prognosis despite absence of anaplastic transformation à seem to behave more like anaplastic gliomas with median survival of 5.16 years
- Study may be limited as 2 MRIs may not accurately determine growth velocity