SDPS-23 CUMULATIVE TUMOR VOLUME THRESHOLD CORRELATES WITH NEUROCOGNITIVE IMPAIRMENT IN PATIENTS WITH NEWLY DIAGNOSED BRAIN METASTASES

OBJECTIVE: To explore the basic situation of cognitive function in patients with initial state of brain metastasis and the potential factors affecting cognitive function, so as to find the critical value of cumulative tumor volume leading to cognitive dysfunction. METHODS: A total of 284 patients who were newly diagnosed with brain metastases and underwent cognitive testing before radiotherapy in Guangdong Sanjiu Brain Hospital from 2016 to 2022 were retrospectively analyzed. The basic demographic information of the patients, KPS at the time of initial diagnosis, the number of brain metastases, the cumulative tumor volume, and the cognitive function test data before treatment were organized. RESULTS: The cognitive impairment occurred in 100/284 patients (the criteria for cognitive impairment is that at least two of the eight sub-tests are less than 1.5 standard deviation or at least one is less than 2 standard deviations). Multivariate analysis showed that the number of tumors was not a factor in cognitive dysfunction. Age, gender, KPS, educational level, and cumulative tumor volume were risk factors affecting cognitive function. The cumulative tumor volume cut-off value for MOCA, HVLT-R immediate memory, HVLT-R delayed memory, VFT, TMT-A, and TMT-B cognitive impairment were 13.608, 13.125, 11.070, 14.523, 11.070, and 11.113 cc, respectively, while cut-off value for SDMT and TOL were 5.435 and 4.528 cc, respectively. CONCLUSIONS: Before treatment, cognitive impairment of brain metastases had no significant correlation with the number of metastases but had a significant correlation with the cumulative tumor volume. The cumulative tumor volume cut-off value involving overall cognitive dysfunction, memory dysfunction, speech dysfunction, and decreased thinking speed is between 11-14.5 cc, and the cumulative tumor volume critical threshold involving executive dysfunction and computational dysfunction is between 4.5-5.5 cc.