Tailoring therapy in colorectal cancer by PET-CT.

Positron emission tomography (PET) using [(18)F]-fluoro-2'-deoxy-D-glucose (FDG) has an added value in the clinical management of patients with colorectal carcinoma (CRC). This includes restaging patients before surgical resection or local recurrence of liver metastases, assessment whether residual lesions are scar or recurrence and in pinpointing recurrence in case of unexplained increase in serum levels of carcinoembryonic antigen. At present, there is an increasing interest in new roles for FDG-PET, especially for characterization of lesions, for prognosis and response prediction and for early evaluation of treatment response to commenced therapy. FDG-PET may lead to better selection of patients for different therapeutic options or to early individual adjustment of current treatment. This systematic review aims to provide an up-to-date overview of literature on the current and potential value of FDG-PET in CRC patients by addressing staging and recurrence detection, prognosis and response prediction and evaluation of preoperative (chemo)radiotherapy for primary rectal carcinoma, ablative treatment for unresectable liver metastases and chemotherapy for advanced CRC.

Impact of [18F]fluorodeoxyglucose positron emission tomography on surgical management of melanoma patients.

BACKGROUND: Several studies have shown adequate sensitivity and specificity of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the detection of metastases from melanoma, but few have addressed its impact on treatment. The aim of this retrospective study was to assess the impact of FDG-PET on treatment of melanoma in three Dutch university medical centres. METHODS: The medical records of 257 patients were reviewed. The indications for FDG-PET and findings were recorded. Unexpected findings of suspected (pre)malignant tumours other than melanoma were assessed. Treatment plans before and after FDG-PET were recorded and analysed to evaluate changes in disease management. RESULTS: Most scans (71.2 per cent) were requested for staging, mainly to detect distant metastases in patients with stage III disease. Overall, 56 patients (21.8 per cent) were upstaged as a result of PET. In 44 patients (17.1 per cent) treatment was changed, usually from surgery to systemic treatment in patients with stage III disease. Unexpected tumours were detected (mainly colorectal) in 11 patients (4.3 per cent). CONCLUSION: FDG-PET is most valuable in patients with stage III melanoma for detection of distant metastases and identification of candidates for surgery and/or systemic treatment. Unexpected FDG-PET findings should not be disregarded, as (pre)malignant, clinically relevant, tumours may be identified.