Pseudoprogression and pseudoresponse according to MRI data after radiosurgical treatment of glioblastoma using metronidazole

Abstract

Aims: to determine response rates to radiosurgical treatment of patients with glioblastoma using hypoxic radiosensitizers based on MRI data to improve diagnosis of true tumor recurrence, or true response to treatment from pseudoprogression and pseudoresponse. Methods. From 106 patients with glioblastoma treated with radiosurgery, we compared the group with the use of radiosensitizers and the control group without it, focusing on the differential diagnosis of pseudoprogression and pseudoresponse from true tumor recurrences and response to treatment, comparing the success of treatment in terms of recurrence-free and overall survival. Results. From the total number of treated patients, signs of pseudoprogression were observed in 30 patients (34.09%) in the period from 3 to 6 months after SRH. A pseudoresponse was observed in 4 patients (4.54%) during the first week, in two patients on the third day, and in two patients on the fifth day after SRH using the hypoxic radiosensitizer metronidazole. The value of ADC in the zone of intermediate hypoxia was important not only for differential diagnosis of pseudoprogression and pseudoresponse from true progression and response, but also for determining predictors of treatment success, for example, an increase in ADC from 0.9-1.0x10-3mm2/s to 1.1 -1.2x10-3mm2/s one week after SRH with radiosensitization was not only an indicator of true response, but also a predictor of relapse-free survival rates over 10 months, and overall - 20 months in the main group. Conclusions. Indicators of perfusion, diffusion and BOLD programs help to carry out differential diagnosis of pseudoprogression, pseudoresponse and true relapses and tumor response to radiosurgical treatment, the study of ADC indicators, which, in addition to high sensitivity and specificity, are predictors of radiosurgical treatment of glioblastoma, deserves special importance.