氟脱氧葡萄糖PET在晚期非小细胞肺癌分期中的应用进展

Utility of FDG PET in staging unresectable non-small cell lung cancer in advanced stage

肺癌是常见恶性肿瘤之一,近10年来其发病率和死亡率都呈明显增高趋势。肺癌生物学特性十分复杂,恶性程度高,约70%的患者在确诊时已属Ⅲ～Ⅳ期。对肺癌进行确切诊断并分期是选择合理治疗方案的前提,随着影像技术特别是氟脱氧葡萄糖正电子发射断层显像(fludeoxyglucosepositronemissiontomography,FDGPET)和相关研究的进展,晚期非小细胞肺癌的诊断策略和分期方法有所变化,并可能对患者的治疗方案和预后评估造成影响,比如,T3N0肿瘤归入ⅡB期而非Ⅲ期,原发瘤所在肺叶内出现卫星转移灶属于M1,即Ⅳ期。对于T、N分期,胸部X线和强化CT仍是最常用的检查手段,但CT扫描应达到足够范围,而FDGPET在探测淋巴结转移中具有独特优势。对于纵隔淋巴结转移的诊断,尤其是临床判断仍有手术指征的病例,纵隔镜仍是不可替代的金标准。对于远处转移及M分期的确定,即使其他各种影像学检查均无阳性发现,FDGPET仍是不可缺少的检查手段,临床检查的重点应包括骨、脑、肝和肾上腺等脏器,但对于难以确定的远处转移,尤其是临床判断有手术指征的病例,通过穿刺活检获得病理或细胞学诊断结果仍是非常重要的。

Lung cancer is still one of the most common and aggressive tumors in the world. About 70% cases with lung cancer are staged Ⅲ or Ⅳ at their first presentation. The diagnostic and staging procedures should be considered in the first place for further research and investigational therapy on advanced non-small cell lung cancer （ANSCLC）. Despite advances in noninvasive methods of staging ANSCLC, including FDG PET scan, a reasonable diagnostic strategy remains important for the accurate staging of cancer to instruct the subsequent treatment. It should he noted firstly that the International System for Staging Lung Cancer has been revised since the last 1997 edition. For example, patients with T3 No tumors are now categorized as stage Ⅱ B instead of stage Ⅲ. Furthermore, the presence of satellite tumor（s） in the ipsilateral lung, in a distant, non-primary tumor lobe, is now categorized as M1 disease. For T and N staging, chest x-ray and chest CT scan with infusion of contrast material are commonly used and the CT scan should extend inferiorly to include the liver and adrenal glands; FDG PET scanning complements to CT scan is essential on many occasions because its accuracy is consistently superior to CT, and mediastinoscopy as the gold standard remains important for the accurate detection of cancer in mediastinal lymph nodes. For the staging of distant metastatic disease, an FDG PET scan is superior to other modalities even when there is no evidence of distant metastatic disease. Careful clinical examinations should be emphasized on the bone, brain, liver, and adrenal. Histologic confirmation remains important to abnormal lesions identified on radiologic imaging if the patient is otherwise considered to he potentially resectable.