The Value of Scintimammography, F‐18 FDG‐PET and PET‐CT in Breast Cancer

Abstract

SummaryDue to the introduction of new lipophilic radiotracers like Tc‐99m Sestamibi or Tc‐99m Tetrofosmin in conventional scintigraphy and the implementation of FDG‐PET in clinical routine in the last decade, their role in primary staging, restaging and therapy monitoring in breast cancer patients has been extensively evaluated.Concerning primary diagnosis, both scintimammography (SMG) and FDG‐PET cannot be recommended for small nodules <1 cm, and biologically low proliferative cancers, like tubular, lobular cancer or DCIS. Nevertheless, FDG‐PET or SMG (when PET is not available) may be useful for selected patients with dense breasts, breast implants and after extensive surgery. In axillary staging, due to its limitation in resolution, both SMG and FDG‐PET cannot be a replacement for sentinel node biopsy or axillary lymph node dissection. Additionally, the number of involved lymph nodes cannot be exactly determined. Nevertheless, by using FDG‐PET, the advantage would be the simultaneous detection of internal mammarian chain lymph node involvement and distant metastases. In restaging, F‐18 FDG‐PET demonstrates apparent advantages in the diagnosis of metastases in patients with breast carcinoma compared with conventional imaging on a patient basis. On a lesion basis, significantly more lymph node and fewer bone metastases can be detected using F‐18 FDG compared with conventional imaging including bone scintigraphy (BS). Concerning bone metastases, sclerotic lesions are predominantly detected by BS, whereas FDG‐PET is more helpful in identifying osteolytic or bone marrow metastases. In patients with clinical suspicion but negative tumour marker profile, F‐18 FDG‐PET seems to be a reliable imaging tool for detection of tumour recurrence or metastases. Given the high predictive value of F‐18 FDG‐PET, tumour stage and therapeutic strategy will be reconsidered in several patients.In conclusion, besides limitations in primary diagnosis and staging, restaging after surgical resection, chemotherapy and external irradiation is the most efficient and cost‐effective indication for F‐18 FDG‐PET in breast cancer. PET/CT provides important additional information about topography and tumour extent and increases specificity.