Opportunistic CT screening for osteosarcopenia predicts reduced overall survival in patients with gastric cancer: a retrospective cohort study.

BACKGROUND

Osteosarcopenia is under-recognized in clinical practice and its specific prognostic value beyond sarcopenia has not been fully elucidated. This study aimed to identify osteosarcopenia using abdominal computed tomography (CT) scans and investigate its influence on survival outcomes in gastric cancer patients.

METHODS

We retrospectively analyzed 1,394 patients who underwent surgical resection for gastric cancer between 2019 and 2024. Of these patients, 838 were included in the study (exclusion rate 39.9%). Demographic data and clinical data were collected and compared. Osteosarcopenia was diagnosed by assessing the skeletal muscle index at the third lumbar vertebra level and bone mineral density at the first lumbar vertebra level on routine CT scans. With a median follow-up of 20 months, the associations between osteosarcopenia, baseline characteristics, and survival outcomes were analyzed.

RESULTS

Osteosarcopenia was diagnosed in 142 (16.9%) patients. Compared with the non-osteosarcopenia group, the osteosarcopenia group had a higher proportion of males, older age, poorer nutritional status, and a lower rate of receiving chemotherapy (all P<0.05), while there were no significant differences in surgical approach or cancer stage between the groups (all P>0.05). Multivariate Cox analysis revealed that cancer stage [II: hazard ratio (HR) =2.973, 95% confidence interval (CI): 1.274-6.937, P=0.01; III: HR =7.133, 95% CI: 3.300-15.415, P<0.001; IV: HR =10.390, 95% CI: 3.641-29.651, P<0.001], chemotherapy (HR =0.491, 95% CI: 0.311-0.776, P=0.002), carbohydrate antigen 199 (CA199) (HR =1.634, 95% CI: 1.020-2.617, P=0.041), patient-generated subjective global assessment (PG-SGA) (HR =1.939, 95% CI: 1.158-3.247, P=0.01), osteoporosis (HR =1.785, 95% CI: 1.019-3.126, P=0.043) and osteosarcopenia (HR =2.291, 95% CI: 1.238-4.239, P=0.008) were associated with poorer overall survival.

CONCLUSIONS

Osteosarcopenia is associated with reduced overall survival in gastric cancer patients after surgical resection. Routine abdominal CT serves as a convenient tool for the opportunistic screening of osteosarcopenia, which could help in nutritional status assessment and intervention development.