| Purpose:To explore the value of diffusion-weighted magnetic resonance imaging(DW-MRI) for the prediction of pathologic response to neoadjuvant chemoradiotherapy(n CRT) in esophageal squamous carcinoma. Material and methods:From December 2013 to December 2015, locally advanced(T2N1-3M0 or T3-4N0-3M0) esophageal squamous cancer patients at our insititute were enrolled in our study. All patients received cisplatin(20 mg per square meter of body-surface area, day1) and paclitaxel(40 mg per square meter of body-surface area,day1) for 4 weeks and concurrent radiotherapy(40 Gy in 20 fractions, 5 days per week) followed by surgery. Patients underwent routine MRI scanning and functional DW-MRI sequences before treatment and after completion of neoadjuvant treatment within 1 week. Esophagectomy was performed 3 to 4 weeks after completing neoadjuvant chemoradiotherapy. The degree of histopathologic tumor regression of resection specimen was assessed by two experienced pathologists. Response was difiened as tumor regression grade(TRG) 1 to 3 and good response as path CR or near-path CR(TRG1 or 2).The predictive potential of initial tumor ADC(pre-ADC), post-treatment ADC(post-ADC) and change in ADC(ΔADC), maximum diameters of tumors(ΔD) after treatment for pathologic response, and good response. Result:16 patients were enrolled in the study. Patients had a median age of 62 years(range:45–71 years), and 10(62.5%) of them were male. Among these patients, 9(56.25%) patients showed response to n CRT, while the remaining 7(43.75%) showed no response. A path CR after n CRT was found in 1 of 16 patients(6.25%), 4 patients achieved near-path CR. The post-ADC was significantly higher than pre-ADC in response group(3.14±0.649×10-3mm2/s vs. 2.24±0.576×10-3mm2/s,P=0.006),as well as in no response group(2.66±0.327×10-3mm2/s vs. 1.72±0.404×10-3mm2/s, P=0.001). The pre-ADC in response group higher than that of no response group(2.24±0.576×10-3mm2/s vs. 1.72±0.404×10-3mm2/s, P=0.061), and there is approach to significant differences between groups. The post-ADC(3.14±0.649×10-3mm2/s vs. 2.66±0.327×10-3mm2/s, P=0.100), ΔADC(45.61±37.23% vs. 60.17±30.41%, P=0.416), ΔD(13.34±13.68% vs. 21.11±18.99%,P=0.100) were not significant differences in response group and no response group. The pre-ADC was predictive of tumor response to n CRT at a threshold of 1.765×10-3mm2/s(sensitivity of 77,8%, specificity of 71.4%, PPV of 77.8%, and NPV of 71.4%,accuracy of 75%, AUC=0.746,P=0.101).The post-ADC was significantly higher in good vs. poor pathologic response patients(3.38±0.78×10-3mm2/s vs. 2.73±0.313×10-3mm2/s,P=0.028) and predictive of good response to n CRT at a threshold of 3.21×10-3mm2/s(sensitivity of 80%, specificity of 100%, PPV of 100%, and NPV of 91.7%, accuracy of 93%,AUC=0.818,P=0.047).No evidence of correlation between pre-ADC(r=-0.284,P=0.286),post-ADC(r=-0.443,P=0.086), ΔADC(r=0.112,P=0.679), ΔD(r=0.119, P=0.662)and TRG scores. Conclusion:In our present study, pre-ADC and post-ADC of tumor, rather than ΔADC and ΔD, has a potential to predict the tumor response to n CRT. It is seemed that patients with the higher pre-ADC showed a better response to neoadjuvant treatment. No relation between ADC, reduction in maximum diameters of tumors and TRG scores. Larger and multi-center studies are needed to validate our findings. |
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