Background and purpose: Leptomeningeal metastasis in gastric cancer is a special form of gastric cancer metastasis to the central nervous system

which has distinct biological characteristics different from other advanced gastric cancers. This study aimed to explore the clinicopathological characteristics and prognostic survival analysis of patients with gastric cancer and leptomeningeal metastasis (GCLM). Methods: The gastric cancer database established by the Third Department of Surgery of the Fourth Hospital of Hebei Medical University from 2010 to 2019 was searched

patients with GCLM confirmed by imaging examination or cerebrospinal fluid cytology were selected

and their clinicopathological characteristics

survival prognosis and related factors of prognosis were analyzed. Results: A total of 50 GCLM patients were retrieved

accounting for 0.82% of the total gastric cancer patients. Among them

30 cases were male (60.00%)

and 20 cases were female (40.00%); the median age was 54 years (95% CI: 41-66 years)

of which 22 cases (44.00%) were less than 50 years

and 28 cases were more than 50 years (56.00%); pathological types: 29 cases of poorly differentiated adenocarcinoma (58.00%)

18 cases of signet ring cell carcinoma and mucinous adenocarcinoma (36.00%)

and 3 cases of mixed neuroendocrine carcinoma (6.00%). The 50 cases of GCLM patients were metachronous meningeal metastases. The median time from the diagnosis of gastric cancer to the onset of GCLM was 13.8 months (95% CI: 5.5-20.9 months)

of which 23 cases had brain damage and meningeal irritation (46.00%)

18 cases had symptoms of cranial nerve function involvement (36.00%)

and 19 cases had symptoms of spinal nerve function impairment (38.00%). The average number of lumbar puncture cerebrospinal fluid examinations in the whole group of patients was 3 times

of which the positive rate of cerebrospinal fluid cytology was 46.00% (23/50) after one puncture

and the positive rate after the second lumbar puncture was 76.19% (32/42). The 3rd positive rate was 77.14% (27/35). The median survival time after meningeal metastasis of the whole group was 3.8 months (95% CI: 1.30-8.60). The results of Cox multivariate analysis showed that the positive expression of the tumor marker CA19-9 in serum (HR=2.458

95% CI: 1.189-5.080

P=0.015) and other distant organ metastases (HR=3.593

95% CI

1.365-9.456

P=0.010) were independent risk factors affecting the prognosis of GCLM patients

while chemotherapy after meningeal metastasis was a protective factor (HR=0.170

95% CI: 0.049-0.591

P=0.005). Conclusion: For patients with late clinical stage of gastric cancer who have headache

nausea and vomiting

accompanied by increased intracranial pressure and meningeal irritation

one should be highly vigilant about the possibility of GCLM. Application of systemic therapy combined with local therapy can help prolong the survival time of patients with GCLM and improve the prognosis.