Perez R O, Habr-Gama A, São Julião G P, Lynn P B, Sabbagh C, Proscurshim I, Campos F G, Gama-Rodrigues J, Nahas S C, Buchpiguel C A
Angelita and Joaquim Gama Institute, Rua Manuel da Nobrega, São Paulo, 1564, Brazil,
Tech Coloproctol. 2014 Aug;18(8):699-708. doi: 10.1007/s10151-013-1113-9. Epub 2014 Feb 8.
Molecular imaging using positron emission tomography/computerized tomography (PET/CT) may add relevant incremental diagnostic information to standard structural cross-sectional imaging. Such information may allow identification of patients with rectal cancer that are more likely to develop complete tumor regression after neoadjuvant chemoradiation therapy (CRT). The objective of this report was to identify PET/CT features that are associated with a complete response after CRT.
99 cT2-4N0-2M0 distal rectal cancer patients (≤7 cm from anal verge) were included in this prospective single center trial (NCT 00254683). Patients underwent baseline PET/CT followed by 54 Gy and 5-fluorouracil-based neoadjuvant CRT. After completion of therapy, patients underwent 6- and 12-week PET/CT. Clinical assessment of tumor response was performed at 12 weeks and was blinded to radiological information. Patients were treated according to clinical assessment.
There were seven patients with a complete pathological response (pCR) and 16 with a complete clinical response (cCR) (23 complete responders). Comparison of pCR exclusively and non-pCR revealed that only baseline primary tumor standard uptake value (SUV) was a significant predictor of response. Comparison of complete responders (pCR or cCR) and non-complete responders showed that depth of rectal wall uptake at baseline PET/CT (p = 0.002) and variation between baseline and 12-week maximum standard uptake value (SUVmax) of primary tumor (p = 0.001) were independent predictors for complete response at multivariate analysis. A decrease >67 % between baseline and 6-week or 76 % between baseline and 12-week SUVmax were associated with complete response (pCR or cCR; p = 0.02 and p < 0.001, respectively).
Positron emission tomography/computerized tomography at baseline, 6 and 12 weeks, may provide information regarding patients with a higher likelihood of developing complete tumor regression following neoadjuvant CRT.
使用正电子发射断层扫描/计算机断层扫描（PET/CT）进行分子成像可能会为标准的结构横断面成像增加相关的增量诊断信息。这些信息可能有助于识别在新辅助放化疗（CRT）后更有可能出现肿瘤完全消退的直肠癌患者。本报告的目的是确定与CRT后完全缓解相关的PET/CT特征。
99例cT2-4N0-2M0期距肛缘≤7 cm的低位直肠癌患者纳入了这项前瞻性单中心试验（NCT 00254683）。患者接受基线PET/CT检查，随后接受基于54 Gy和5-氟尿嘧啶的新辅助CRT。治疗结束后，患者接受6周和12周的PET/CT检查。在12周时对肿瘤反应进行临床评估，且评估人员对放射学信息不知情。患者根据临床评估进行治疗。
有7例患者出现完全病理缓解（pCR），16例出现完全临床缓解（cCR）（共23例完全缓解者）。仅比较pCR组和非pCR组发现，只有基线原发肿瘤标准摄取值（SUV）是反应的显著预测因素。比较完全缓解者（pCR或cCR）和非完全缓解者发现，基线PET/CT时直肠壁摄取深度（p = 0.002）以及原发肿瘤基线与12周最大标准摄取值（SUVmax）之间的变化（p = 0.001）在多变量分析中是完全缓解独立预测因素。基线与6周之间SUVmax下降>67%或基线与12周之间下降76%与完全缓解（pCR或cCR）相关（分别为p = 0.02和p < 0.001）。
基线、6周和12周时的正电子发射断层扫描/计算机断层扫描可能为新辅助CRT后更有可能出现肿瘤完全消退的患者提供信息。
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