18F-FET PET scans identify GMB recurrence and therapeutic reactive changes

Backgroundconventional MRI examination was not easy to distinguish between glioblastoma (GBM) recurrence and therapeutic reactive changes, because relapse and therapeutic reactive changes often occurred at the site of the original lesions, radiology characteristics were similarThe distinction between GBM recurrence or therapeutic reactive changes had a significant effect on follow-up treatment and prognosisEarly detection of tumor recurrence is the key to optimizing individual treatment, improving prognosis and prolonging overall survival (OS)The gold standard for verifying recurrent or false progression is a tissue specimen obtained by surgery, but there is a risk of surgery or tissue biopsyTherefore, it is important to identify a reliable non-invasive imaging biomarker replacement surgery to identify tumor residues or recurrences and therapeutic reactive changesThe study found that gliomas over-expressed a variety of L-amino acid transport proteins (LATs), O-
18F-fluoroethnoe-ethyls)-O-(2-
18
-F-fluorothyl-yl-L-tyrosine,18F-FET) as an LAT substrate, an amino acid trace of brain tumor PET scanning18
F-FET has a high intake rate in brain tumors and a low in normal brain tissue, especially between malignant tumors and normal brain tissueAsma Bashir, of the Nuclear Medicine and PET Center at Copenhagen National University Hospital, and others assessed the 20-minute resting state18 F-PET in identifying GBM recurrence, therapeutic reactive changes, and predicting the effects of OS The results were published in The Neuro-Oncol in December 2019 research methods
the study performed a 18 F-FET PET scan scan of adult patients diagnosed with a suspected recurrence of GBM for MRI between November 2011 and March 2019 Patients were given a rest-state PET scan 20 minutes after injecting 18 F-FET, the results of which were compared with MRI-T1-weighted enhanced imaging and T2 or FLAIR-weighted imaging fusion Record the maximum and average ratio (TBRmax, TBR) in tumor tracers' intake, and calculate the maximum and average ratio of tumor tissue activity concentration to the average activity concentration of the normal cortex in the opposite hemisphere According to current international standards, the volume of biotumor (BTV) per cm3 is calculated at a tumor activity concentration (tumor activity concentration) of 1.6 times the average background activity concentration During the data collection process, try to ensure that GBM's diagnosis meets the 2016 EDITION of who central nervous system tumor classification criteria "Relapsed GBM" indicates a large number of high density tumor cell regions that are now similar to primary GBM "Therapeutic reactive change" refers to no or only a small number of living tumor cells in necrotist tissue after treatment In a mixture of GBM and therapeutic reactive changes, it is classified by a committee-certified neuropathologist based on the presence of a large number of tumor cell tissue on MRI imaging before 18 F-FET PET scans, THE RECURRENCE OR PROGRESS OF GBM CAN BE INITIALLY DETERMINED ACCORDING TO IMPROVED RANO STANDARDS: ON MRI-T1-WEIGHTED BOOSTERS, THE LESIONS SIZE INCREASED BY 25%, OR THE APPEARANCE OF A NEW ENHANCED LESIONS OF 10MM IN BOTH VERTICAL DIRECTIONS, OR A SIGNIFICANT INCREASE IN LESIONS ON UNENHANCED MRI-T2/FLAIR WEIGHTED FILMS A point-like, difficult-to-measure lesions appear in the surgical cavity, even when there is only a vertical diameter of 10mm of the lesions, is considered a preliminary advance of the lesions According to the improved RANO standard, not all lesions must be confirmed by MRI before 18 F-FET PET scans If there is no subsequent histopathological diagnosis, MRI follow-up after 18 F-FET PET scans can be used as a reference for GBM recurrence/progression or therapeutic reactive changes After 18 F-FET PET scans, an MRI review is usually performed at least 2 weeks later "Disease progression" means that when patients use corticosteroids increase or are undergoing chemotherapy, MRI tablets see an increase in the growth of enhanced and non-enhanced lesions The size is not measurable or the lesions 10mm cannot be considered lesions relapse/progression, but there must be close imaging follow-up "Therapeutic reactive change" refers to the lesions that were previously enhanced or not enhanced without starting to adjust treatment measures, and follow-up for at least 6 months was stable or reduced In addition, the clinical deterioration caused by tumor growth can also be considered to be the progression of the lesions Total lifetime refers to the time from the patient's 18 F-FET PET examination to the time of death or last follow-up results 18 F-FET PET scans and 64 cases of clinical and imaging follow-up, 152 cases of GBM recurrence and 16 therapeutic reactive changes 18 F-FET parameters in patients with relapsed GBM were significantly higher than those of patients with therapeutic reactive changes (TBRmax, 3.2 to 1.6; TBRmean, 2.0 to 1.6; BTV, 14.8cm3 to 0.01cm3;P 0.0001) THE ROC ANALYSIS SHOWED THAT THE OPTIMAL THRESHOLD FOR TBRMAX WAS 2.0, TBR1.8, BTV WAS 0.55CM3, AND TBRMAX WAS THE BEST INDICATOR TO DISTINGUISH BETWEEN GBM RECURRENCE AND THERAPEUTIC REACTIVE CHANGES (SENSITIVITY 99%, 94% SPECIFICITY AND 99% ACCURACY ;P 0.0001), FOLLOWED BY BTV (SENSITIVITY 98%, 94% SPECIFICITY AND 98% ;P 0.0001) participants in the study followed up with 18 F-FET PET scans for 1-71.5 months, with a median 6 months During the follow-up period, 124 patients (84.9%) died Single-factor analysis, age, sex, degree of previous tumor removal, MGMT methylation, IDH1 mutation and OS were not significantly correlated TBRmax rise (HR?1.328;95% CI, 1.116-1.582; P-0.001), log BTV rise (HR?1.303; 95% CI, 1.179-1.439; P 0.0001), corticosteroid daily use of 10mg (HR?3.202; CI5.48-45.48.48.48.78.48.78.78.78.78.78.78.78.78.78.78.78.78.7 51; P 0.0001), Physical Condition (performance status, PS) index 1 (HR?1.856; 95% CI, 1.060-3.249; P-0.030) was significantly related to OS shorter; subsequent second-line chemotherapy (HR-0.650;95% CI, 0.450-0.938; 0.450-0.038; P.02) was significantly related to OS In the multi-factor analysis, the factors associated with OS's significant independence were log BTV (HR?1.339; 95% CI, 1.196-1.498; P 0.0001), use of corticosteroids (HR 2.035;955 % CI, 1.321-3.134; P-0.001) and subsequent second-line chemotherapy (HR-0.448; 95% CI, 0.295-0.681; P 0.0001) TBRmax has no predictable OS effect (HR?1.095; 95% CI, 0.821-1.459; P.537) The analysis of the relapsed GBM subgroup found that an increase in log BTV (HR?1.185; 95% CI, 1.048-1.340; P-0.007) was associated with shorter OS conclusions , in patients with suspected recurrence of GBM, 20 minutes resting 18 F-FET PET scan is an effective method to identify the changes in GBM recurrence and therapeutic reactive effect situated by MRI imaging tablets, with a diagnostic accuracy of up to 99%, and an prediction of OS However, the authors suggest that the treatment of recurrent GBM is more complex, and in a few cases, due to the occasional false negative or false positive results, a single point in time of 18 F-FET PET scanmay may not be sufficient to guide further tumor treatment, so the patient's prognosis as the progression of the disease is taken into account throughout the course of the disease.