Capirci Carlo, Rubello Domenico, Chierichetti Franca, Crepaldi Giorgio, Carpi Angelo, Nicolini Andrea, Mandoliti Giovanni, Polico Cesare
Radiotherapy Department, S. Maria della Misericordia Rovigo Hospital, ASL 18, Rovigo, Italy.
Biomed Pharmacother. 2004 Oct;58(8):451-7. doi: 10.1016/j.biopha.2004.08.005.
Multimodality treatment of loco-regional advanced rectal cancer has demonstrated to improve local control and overall survival. Proctoscopy, digital rectal examination (DRE), computer tomography (CT), endorectal ultrasound (ERUS), and magnetic resonance imaging (MRI) cannot correctly detect downstaging in rectal tumors after chemo radiation therapy (CRT). New imaging techniques, like 18F-FDG PET, may play some role in predicting the pathologic response to CRT before surgical resection. Aim of the present study was to further investigate the accuracy and predictive value of 18F-FDG PET in a large series of patients with rectal cancer treated with preoperative intensified CRT. Between January 2000 and December 2003, 81 patients with histologically proven adenocarcinoma in clinical stage II-III disease, according to criteria of TNM classification, were included in this study. All patients were submitted to diagnostic staging workup with DRE, proctoscopy with biopsy, ERUS, CT scan of the abdomen and pelvis or pelvic MRI plus liver ultrasonography, coloscopy or barium colonic enema. One month later the end of CRT all patients were submitted to diagnostic restaging work-up (DRW) and 18F-FDG PET. Surgery was performed 8-9 weeks after the end of CRT and pathologic stage was defined. Moreover a pathologic assessment of tumor regression was made with tumor regression grade score (TRG). PET correctly identified 22/28 (79% specificity) patients with complete pathologic response (pCR). However, sensitivity was 45% (24/53) while PPV, and NPV were equal to 77 and 43%, respectively. Total PET accuracy rate was 56%. PET sensitivity increased from 45 to 56% if the end-point was pCR, or TRG score, respectively. The best correlation was found between PET findings and pathologic stage (P <0.01) or TRG score (P <0.01). The accurate identification of rectal cancer patients with major pathological response after preoperative CRT further supports the necessity of designing prospective studies with new and more accurate was imaging technologies with the main object of offering conservative treatment in responder patients.
局部晚期直肠癌的多模式治疗已证明可改善局部控制率和总生存率。直肠镜检查、直肠指诊（DRE）、计算机断层扫描（CT）、直肠内超声（ERUS）和磁共振成像（MRI）无法正确检测化疗放疗（CRT）后直肠肿瘤的降期情况。新的成像技术，如18F-FDG PET，可能在手术切除前预测CRT的病理反应中发挥一定作用。本研究的目的是进一步调查18F-FDG PET在一大系列接受术前强化CRT治疗的直肠癌患者中的准确性和预测价值。2000年1月至2003年12月，根据TNM分类标准，81例临床II-III期组织学证实为腺癌的患者纳入本研究。所有患者均接受了DRE、活检直肠镜检查、ERUS、腹部和盆腔CT扫描或盆腔MRI加肝脏超声检查、结肠镜检查或钡剂结肠灌肠的诊断性分期检查。CRT结束1个月后，所有患者均接受诊断性再分期检查（DRW）和18F-FDG PET检查。CRT结束8-9周后进行手术，并确定病理分期。此外，用肿瘤退缩分级评分（TRG）对肿瘤退缩进行病理评估。PET正确识别出22/28例（特异性79%）完全病理缓解（pCR）患者。然而，敏感性为45%（24/53），而阳性预测值（PPV）和阴性预测值（NPV）分别为77%和43%。PET总准确率为56%。如果终点分别为pCR或TRG评分，PET敏感性从45%提高到56%。PET结果与病理分期（P<0.01）或TRG评分（P<0.01）之间的相关性最佳。术前CRT后准确识别有主要病理反应的直肠癌患者进一步支持了开展前瞻性研究的必要性，这些研究采用更新、更准确的成像技术，主要目的是为反应者患者提供保守治疗。
