[Skull base meningioma: Clinical and radiological efficacy based on a quantitative volumetric analysis]

To date, no correlation has been found between clinical and radiological efficacy after irradiation of skull base meningiomas. However, the evaluation of the radiological response was most often made by questionable methods that may have underestimated the radiological effectiveness of radiotherapy. The objective of this work is to verify this hypothesis by quantitative volumetric analysis.

Data from 35 patients treated with either helical tomotherapy (45.7%) or fractionated stereotactic radiotherapy (54.3%) were retrospectively analysed. These were mainly women (94%) aged 59 (43-81) with lesions mainly of the cavernous sinus (60%). There was a median of 2 (1-4) symptoms and the main symptoms were visual impairment (39%), cranial nerve deficits (23.4%) and headaches (17.2%).

Median tumour volume decreased significantly (P<0.05) from 9.6mL (0.3-36.6) to 6.8mL (0.1-26.5) after median follow-up of 44 months (24-77). Sixty-three percent of patients had an improvement of at least one symptom. In univariate analysis, clinical efficacy (P<0.05), radiotherapy technique (P<0.05), tumor topography (P<0.05) and initial tumor volume (P<0.05) were predictive factors for radiological response. In multivariate analysis, only the inverse correlation between radiological response and initial tumor volume remained significant (ρ: -0.47 95% CI -3.2 to 5.7; P<0.05).

The quantitative volumetric monitoring demonstrates a major radiological efficiency of radiotherapy. However, no clear correlation between clinical and radiological efficacy was found.