[Clinical characteristics and prognosis of brain metastasis in locally advanced rectal cancer].

<b>Objective:</b> To investigate the clinical characteristics of brain metastases after radical surgery for locally advanced rectal cancer (LARC). <b>Methods:</b> The clinical characteristics of LARC with brain metastases treated in the Department of General Surgery, Peking Union Medical College Hospital from 2013 to 2023 were retrospectively analyzed. The inclusion criteria were rectal adenocarcinoma within 15 cm of the anal verge and having undergone radical surgery, and the exclusion criterion was primary malignant tumor of the brain. The main outcomes were overall survival (OS), disease-free survival (DFS), and disease-specific overall survival (determined as the interval between occurrence of brain metastasis to death from any causes). The Kaplan-Meier method was used for survival analysis. <b>Results:</b> We identified 4500 patients with LARC, 20 (0.4%) of whom had brain metastases. The mean age of patients with brain metastases was 63.8±9.3 years. They comprised five women and 15 men. The brain was the first site of metastasis in four patients (20%) whereas 18 patients had heterochronous extracranial metastases before brain metastasis. Two patients also had multi-organ metastases. The most common manifestations of brain metastases were dizziness and headache (five patients, 25%), sudden onset of limb weakness (four, 20%), sudden speech impairment (two, 10%), and polyopia (two, 10%). The metastases were diagnosed during follow-up in three patients (15%). Four of the patients were asymptomatic (20%). Treatment approaches included surgical resection (six patients, 30%), chemoradiotherapy (nine, 45%), and palliative (five, 25%). The median follow-up time was 45.5 (4-112) months until October 2023. 1y-OS, 3y-OS, and 5y-OS were 95.0%, 62.9%, and 43.3%, respectively. 1y-DFS, 3y-DFS, and 5y-DFS were 55.0%, 25.0%, and 5.0%, respectively. With brain metastasis as the starting point, the median duration of survival was 16 (10.2-21.8) months. <b>Conclusion:</b> The incidence of brain metastasis is relatively low in patients with LARC, who often have multiple synchronous extracranial metastases. Brain metastases lack specific manifestations and more often occur in male patients. Surgical intervention or combined radiotherapy and chemotherapy may improve disease-specific survival to a certain extent. However, the overall prognosis remains poor.