Association between the apparent diffusion coefficient and the preoperative chemotherapy response of patients with locally advanced gastric cancer

BACKGROUND: The apparent diffusion coefficient is a parameter measured by magnetic resonance imaging (MRI). Studies in breast cancer and osteosarcoma have shown that the apparent diffusion coefficient has a good correlation with the efficacy of neoadjuvant chemotherapy. However, to date, no studies have evaluated the association between the apparent diffusion coefficient and the preoperative chemotherapy response of patients with locally advanced gastric cancer. METHODS: The data of 143 patients with locally advanced gastric cancer admitted to Zhejiang Medical and Health Group Quzhou Hospital (Zhejiang Quhua Hospital) from January 2018 to January 2019 were retrospectively collected. All the patients underwent preoperative chemotherapy and dynamic enhanced MRI to analyze the correlation between the apparent diffusion coefficient and preoperative chemotherapy response. RESULTS: Compared to the control group, the apparent diffusion coefficient of the objective remission group was significantly increased [(1.16±0.26) ×10(−3) vs. (0.95±0.26) ×10(−3) mm(2)/s, P<0.001]; the rate of the apparent diffusion coefficient >1.095×10(−3) mm(2)/s was significantly increased (61.29% vs. 30.00%, P<0.001). The apparent diffusion coefficient was valuable in predicting objective remission after preoperative chemotherapy in patients with locally advanced gastric cancer, the area under the curve (AUC) was 0.708 [95% confidence interval (CI): 0.621–0.796, P<0.001], the best diagnostic cut-off value was 1.095×10(−3) mm(2)/s, and the sensitivity and specificity were 0.613 and 0.700, respectively. The multivariate logistics regression analysis showed that the apparent diffusion coefficient of >1.095×10(−3) mm(2)/s was associated with the objective response of patients with locally advanced gastric cancer after preoperative chemotherapy [P=0.004, relative risk =3.135 (95% CI: 1.452–6.768)]. The apparent diffusion coefficient was valuable in predicting the non-recurrence of locally advanced gastric cancer patients, and the AUC was 0.647 (95% CI: 0.557–0.738, P=0.003). The apparent diffusion coefficient was also valuable in predicting the postoperative survival of patients with locally advanced gastric cancer, and the AUC was 0.630 (95% CI: 0.537–0.723, P=0.007). CONCLUSIONS: The elevated apparent diffusion coefficient was associated with objective remission of the preoperative chemotherapy response and prognosis of patients with locally advanced gastric cancer.