因正子造影之廣泛臨床應用，癌症病患被同時發現兩種原發性癌症的頻率持續增加。然而，不論是同時發現或不同時發現的三種不同原發性癌症卻罕?報告。一位69歲女性在200l年接受右乳癌手術與化療，在隨後5年追蹤期間，第二種與第三種原發性癌在不同時期被氟－18-去氟葡萄糖正子造影(FDG-PET)發現。先是2003年5月到6月肺癌被證實且進行手術，到了2006年3月所做的FDG-PET在右肺肺門附近發現一個具有生物活性的殘存病灶，同時在升結腸看到一個局部FDG攝取增加區域。當時病人並無症狀而且血清CEA值正常，該病灶被證實是大腸癌，且是不同時間發現的第三種原發性癌。全身FDG-PET不僅可作?早期偵測存活殘餘腫瘤的重要工具，同時也能早期偵測身體其他部位不同時期發生的癌症。

The frequency of double primary cancers synchronously found in an individual has been increasing. However, synchronous or asynchronous triple primary cancers have rarely been reported. A 69-year-old female received an operation for right breast cancer and subsequent chemotherapy in 2001. During the 5-year follow-up period, second and third primary cancers were asynchronously detected by FDG-PET. Lung cancer was identified and surgery was performed in May and June 2003, respectively. Follow-up FDG-PET performed in March 2006 revealed a biologically active (viable) residual tumor in the perihilar region of the right lung. Surprisingly, an additional focal area with increased FDG uptake in the ascending colon was noted. The patient was symptom-free and had a normal serum CEA level. The lesion was proved to be colon cancer, a third primary cancer asynchronously found in this patient. Whole-body FDG-PET is not only an important tool for the early detection of viable residual tumors in patients with malignancy but also early detection of asynchronously developing cancers in other parts of the body.