Abstract
BACKGROUND: To investigate the prognostic value of the apparent diffusion coefficient (ADC) calculated from diffusion-weighted imaging (DWI) to cytoreductive surgery (CRS), with or without hyperthermic intraperitoneal chemotherapy (HIPEC), for gastric cancer (GC) patients with peritoneal metastasis (PM). METHODS: Between May 2016 and December 2020, 95 newly diagnosed GC patients with PM who underwent CRS combined with HIPEC (CRS + HIPEC group, n = 61) and CRS alone (CRS group, n = 34) were retrospectively included. All patients underwent abdominal 3.0 T MRI scan, including DWI, and the mean ADC (ADC(mean)), minimum ADC (ADC(min)), and maximum ADC (ADC(max)) values of the whole-volume tumor were measured. The prognostic value of the ADC parameters and clinical and histopathological characteristics were investigated by univariate and multivariate Cox analyses. RESULTS: The median overall survival (OS) periods of the CRS + HIPEC and CRS groups were 18 and 9 months, respectively ([hazard ratio (HR) = 0.44 [95% CI: 0.27-0.71], P<0.001). The ADC(mean) and ADC(min) values were positively correlated with OS in all patients (Spearman's rho [R] = 0.361 and 0.470), as well as in the CRS + HIPEC (R = 0.369 and 0.417) and CRS (R = 0.192 and 0.409) groups. The multivariate Cox analysis demonstrated that the ADC(mean) ≤ 1.39 × 10(- 3) mm(2)/s and ADC(min) ≤ 0.77 × 10(- 3) mm(2)/s were significantly associated with a negative prognosis in the total population (HR = 1.68 [95% CI: 1.02-2.75] and 2.48 [95% CI: 1.51-4.08], P all < 0.05) and the CRS + HIPEC group (HR = 2.22 [95% CI: 1.19-4.14] and 2.37 [95% CI: 1.26-4.37], P all < 0.05), along with pathologic T and N stages. Only the ADC(min) ≤ 0.77 × 10(- 3) mm(2)/s was identified as an independent prognostic factor in the CRS group (HR = 3.49 [95% CI: 1.19-10.20], P = 0.022). CONCLUSIONS: The minimum ADC was identified as a strong independent prognostic factor for GC patients with PM who underwent CRS, with or without HIPEC.