Abstract: Objective:To investigate the computed tomography (CT) features of adenocarcinoma of esophagogastric junction (AEG) after neoadjuvant chemotherapy.
Methods:The retrospective and descriptive study was conducted. The clinicopathological data of 59 patients with AEG who underwent neoadjuvant chemotherapy in Peking University Cancer Hospital from February 2010 to November 2014 were collected. There were 51 males and 8 females, aged from 46 to 82 years, with a median age of 63 years. All the 59 patients underwent enhanced CT examination before and after neoadjuvant chemotherapy. Observation indicators: (1) pathological examination and neoadjuvant chemotherapy of patients with AEG; (2) results of CT examination in patients with AEG, including ① qualitative indicators of CT and ② quantitative indicators of CT. Measurement data with skewed distribution were represented as M(P25,P75) or M (range), and comparison between groups was analyzed using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was analyzed by the chi-square test.
Results:(1) Pathological examination and neoadjuvant chemotherapy of patients with AEG: of the 59 patients with AEG, high-differentiated adenocarcinoma was observed in 1 patient, moderate-differentiated adenocarcinoma in 40 patients, and low-differentiated adenocarcinoma in 18 patients. Effective response to neoadjuvant chemotherapy was observed in 13 patients, including 6 patients of pathological tumor regression grading (pTRG) 0 and 7 of pTRG 1; poor response was observed in 46 patients, including 12 patients of pTRG 2 and 34 patients of pTRG 3. (2) Results of CT examination in patients with AEG. ① Qualitative indicators of CT: for the 13 patients with effective response to neoadjuvant chemotherapy, 13 had the presence of ulcers, 5 had layered enhancement, 10 had infiltration of adventitia surface, and 2 had positive extramural venous invasion (EMVI) before neoadjuvant chemotherapy; after neoadjuvant chemotherapy, 13 had shallowed or disappeared ulcers, 7 patients had changed enhancement pattern, 3 had infiltration of adventitia surface, and 1 had positive EMVI. For the 46 patients with poor response to neoadjuvant chemotherapy, 28 had the presence of ulcers, 18 had layered enhancement, 37 had infiltration of adventitia surface, and 22 had positive EMVI before neoadjuvant chemotherapy; after neoadjuvant chemotherapy, 23 had shallowed or disappeared ulcers, 7 patients had changed layered enhancement pattern, 33 had infiltration of adventitia surface and 21 had positive EMVI, respectively. There was no significant difference in the layered enhancement or infiltration of adventitia surface before neoadjuvant chemotherapy between patients with different treatment response (x²=0.002, 0.000, P>0.05). There were significant differences in the presence of ulcers and positive EMVI before neoadjuvant chemotherapy between patients with different treatment response (x²=5.591, 4.421, P<0.05). After neoadjuvant chemotherapy, there were significant differences in the changes of layered enhancement pattern, infiltration of adventitia surface and positive EMVI between patients with different treatment response (x²=6.359, 10.090, 4.728, P<0.05); while there was no significant difference in the shallowed or disappeared ulcers between patients with different treatment response (x²=1.239, P>0.05). ② Quantitative indicators of CT: for the 13 patients with good response to neoadjuvant chemotherapy, the maximum tumor height, the maximum tumor area, enhanced CT value of the lesion before neoadjuvant chemotherapy were 1.37 cm(0.94 cm,1.88 cm), 8.9 cm² (4.7 cm², 9.9 cm²), 53 HU(47 HU,63 HU), respectively. After neoadjuvant chemotherapy, the above indicators were 1.17 cm (0.79 cm,1.29 cm), 4.4 cm²(2.5 cm²,6.1 cm²), 30 HU(25 HU,53 HU), respectively. The change rates of the maximum tumor height, the maximum tumor area, and enhanced CT value of the lesion were -23% (-42%,9%), -51%(-60 %,-21%), -44%(-51%,19%), respectively. For the 46 patients with poor response to neoadjuvant chemotherapy, the maximum tumor height, the maximum tumor area, enhanced CT value of the lesion were 1.57 cm(1.21 cm,1.96 cm), 9.4 cm²(6.6 cm²,13.1 cm²), 60 HU(53 HU,66 HU) before neoadjuvant chemotherapy, respectively. After neoadjuvant chemotherapy, the above indicators were 1.16 cm(0.94 cm,1.37 cm), 6.2 cm²(4.8 cm²,8.1 cm²), 55 HU(47 HU,65 HU), respectively. The change rates of the maximum tumor height, the maximum tumor area, and enhanced CT value of the lesion were -27%(-38%, -9%), -33%(-47%,-12%), -9%(-22%,9%), respectively. There was no significant difference in the maximum tumor height, the maximum tumor area, enhanced CT value of the lesion before neoadjuvant chemotherapy between patients with different treatment response (Z=-1.372, -1.372, -1.331, P>0.05). There was no significant difference in the maximum tumor height after neoadjuvant chemotherapy between patients with different treatment response (Z= -0.503, P>0.05), while there were significant differences in the maximum tumor area and CT value of the lesion (Z=-2.743,-3.049, P<0.05). There was no significant difference in the change rate of the maximum tumor height or the maximum tumor area between patients with different treatment response (Z=0.000, -1.481, P>0.05), while there was a significant difference in the change rate of CT value of the lesion (Z= -3.231, P<0.05).
Conclusion:Effective response of AEG to neoadjuvant chemotherapy was characterized by the changes in tumor layered enhancement pattern, reduction in the maximum tumor area, reduced CT value of the lesion, negative infiltration of adventitia surface, and negative EMVI.