Role of FDG-PET/CT in revealing solitary liver metastasis

Abstract

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Objectives: To establish the role of FDG-PET/CT in diagnosis solitary liver metastasis candidable to surgical resection.

Methods: 27 pts (14 M, 23 F, mean age 57 +/- 12 yrs) previously treated for a primary cancer (NSCLC cancer in 12 cases, colo-rectal ca. in 13, breast ca. in 2) were diagnosed as being affected by solitary liver metastasis at contrast enhanced CT scan (c.e.CT) and ultrasound (conventional imaging). On the basis of conventional imaging they were selected for surgical epatic metastatic resection. Before surgery, these patients were investigated by FDG PET/CT performed by a hybrid PET/CT system (GE, Discovery LS) in fasting condition. FDG 5.4 MBq/kg b.w. was injected 1 hr before examination.

Results: FDG-PET visualized additional metastatic deposits in liver (3 sub-capsular metastatic foci in 2 pts), and metastases to distant site (lombo-aortic lymph nodes in 3 pts, mediastical lymph nodes in 2, adrenal metastasis in 1). These finding changed therapeutic strategy in 7 pts, who were shifted to sistemic chemotherapy. As a whole, FDG-PET/CT allowed to modify therapeutic approach in 7 pts (26% of cases) in our series. The follow-up up period was 4 mo. to 4 yrs, median 18 mo.

Conclusions: Our preliminary data confirm the high sensitivity of FDG PET/CT in detecting unknown metastatic deposits in pts with evidence of a solitary metastatis in the liver at conventional imaging (c.e.CT and ultrasound), especially as regard to occult metastases in distant sites. In our series, on the basis of information derived from the FDG-PET/CT, the therapeutic strategy was changed in 26% of cases. A prolonged follow-up is necessary to establish the long-term impact of the FDG-PET/CT in disease-free rate and survival of these pts.