Abstract：Objective To explore the clinical characteristics of posterior reversible encephalopathy syndrome (PRES) induced by bevacizumab. Methods Relevant databases at home and abroad were searched as of August 2020 and the case reports of PRES induced by bevacizumab were collected. The basic information of the patients, application of bevacizumab (usage and dosage, single use or combined use, combination regimen, etc.), occurrence time of PRES, clinical manifestations, imaging characteristics, intervention measures and outcomes, etc. were recorded and descriptively analyzed. Results A total of 25 patients derived from 21 literature were enrolled in the study, including 6 males and 19 females, aged from 6 to 72 years with a median age of 52 years. The primary diseases were colorectal cancer in 13 patients, breast cancer in 4 patients, lung adenocarcinoma in 2 patients, and each cholangiocarcinoma, liver cancer, ovarian cancer, renal cell carcinoma, hepatoblastoma, and glioblastoma in 1 patient respectively. Seven patients had a history of hypertension. Twenty-one patients were treated with bevacizumab combined with chemotherapy, and the other 4 were treated with bevacizumab alone. PRES occurred from 16-hours to 196 days after first use of bevacizumab, mostly within 21 days after the last medication. The main clinical manifestations included blood pressure elevation (in 21 patients), generalized tonic-clonic seizures (in 17 patients), persistent headache and dizziness (in 12 patients), coma or disturbance of consciousness (in 11 patients), visual impairment or vision loss (in 9 patients), nausea and vomiting (in 6 patients), language impairment or aphasia (in 5 patients), etc. Twenty-four patients underwent head magnetic resonance imaging and the results showed that vasogenic brain edema occurred in occipital lobe, parietal lobe, frontal lobe, cerebellum, or temporal cortex; one patient underwent head computed tomography examination and the result showed mild atrophy of the posterior cerebellum. After the diagnosis of PRES, all the 25 patients stopped taking bevacizumab and received symptomatic treatments. Twenty-three patients had normal blood pressure and relieved symptoms 2-13 days later with imaging examinations showing disappeared brain lesions after 9 days to 10 weeks (2 of which finally died because their condition of PRES worsened later), and the other 2 patients died because their symptoms were not relieved after symptomatic treatments. Two patients resumed bevacizumab treatment after the clinical symptoms and brain lesions in imaging examination disappeared completely, and PRES did not recur. Conclusions The time from the application of bevacizumab to the occurrence of PRES is various, mostly within 21 days after the last application. The clinical and imaging manifestations of PRES induced by bevacizumab are similar to those of PRES caused by other factors. After stopping bevacizumab and receiving symptomatic treatments, most patients could have a good prognosis. It should be alert to the deterioration of the PRES which can lead to death.
