Incidental Second and Third Primary Cancers Asynchronously Detected by FDG-PET in a Patient with Breast Cancer

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.