Bastiaan Wiering

Improved Selection of Patients for Hepatic Surgery of Colorectal Liver Metastases with 18 F-FDG PET: A Randomized Study

With the increasing possibilities for surgical treatment of colorectal liver metastases, careful selection of patients who may benefit from surgical treatment becomes critical. The addition of PET to 18F-FDG may significantly improve conventional staging by CT. Up to now, definitive evidence that the addition of 18F-FDG PET to conventional staging leads to superior clinical results and improved clinical management in these patients has been lacking. In this randomized controlled trial in patients with colorectal liver metastases, we investigated whether the addition of 18F-FDG PET is beneficial and reduces the number of futile laparotomies. Methods: A total of 150 patients with colorectal liver metastases selected for surgical treatment by imaging with CT were randomly assigned to CT only (n = 75) or CT plus 18F-FDG PET (n = 75). Patients were followed up for at least 3 y. The primary outcome measure was futile laparotomy, defined as any laparotomy that did not result in complete tumor treatment, that revealed benign disease, or that did not result in a disease-free survival period longer than 6 mo. Results: Patient and tumor characteristics were similar for both groups. The number of futile laparotomies was 34 (45%) in the control arm without 18F-FDG PET and 21 (28%) in the experimental arm with 18F-FDG PET; the relative risk reduction was 38% (95% confidence interval, 4%−60%, P = 0.042). Conclusion: The number of futile laparotomies was reduced from 45% to 28%; thus, the addition of 18F-FDG PET to the work-up for surgical resection of colorectal liver metastases prevents unnecessary surgery in 1 of 6 patients.

A novel iterative method for lesion delineation and volumetric quantification with FDG PET.

ObjectivesThe determination of lesion boundaries on FDG PET is difficult due to the point-spread blurring and unknown uptake of activity within a lesion. Standard threshold-based methods for volumetric quantification on PET usually neglect any size dependence and are biased by dependence on the signal-to-background ratio (SBR). A novel, model-based method is hypothesized to provide threshold levels independent f the SBR and to allow accurate measurement of volumes down to the resolution of the PET scanner. MethodsA background-subtracted relative-threshold level (RTL) method was derived, based on a convolution of the point-spread function and a sphere with diameter D. Validation of the RTL method was performed using PET imaging of a Jaszczak phantom with seven hollow spheres (D=10–60 mm). Activity concentrations for the background and spheres (signal) were varied to obtain SBRs of 1.5–10. An iterative procedure was introduced for volumetric quantification, as the optimal RTL depends on a priori knowledge of the volume. The feasibility of the RTL method was tested in two patients with liver metastases and compared to a standard method using a fixed percentage of the signal. ResultsPhantom data validated that the theoretically optimal RTL depends on the sphere size, but not on the SBR. Typically, RTL=40% (D=15–60 mm), and RTL>50% for small spheres (D<12 mm). The RTL method is better applicable to patient data than the standard method. ConclusionsBased on an iterative procedure, the RTL method has been shown to provide optimal threshold levels independent of the SBR and to be applicable in phantom and in patient studies. It is a promising tool for lesion delineation and volumetric quantification of PET lesions.

Controversies in the Management of Colorectal Liver Metastases: Role of PET and PET/CT

Positron emission tomography (PET) using [F-18]-2-deoxy-2-fluoro-D-glucose (FDG) has emerged as a promising diagnostic modality in recurrent colorectal cancer. Data in the literature show that the addition of FDG-PET changes patient management in up to 30% of patients with potentially resectable liver metastases, mainly by detecting previously unknown extrahepatic disease. Furthermore, FDG-PET is useful in the follow-up of patients who underwent surgical procedures of the liver, since it is sensitive in detecting residual or relapse malignancy in scarred liver tissue following both resection and local ablative techniques. For follow-up during systemic therapy, early FDG-PET appears predictive for response to therapy. FDG-PET, computerized tomography and magnetic resonance imaging are complementary techniques in staging and restaging patients with advanced colorectal cancer. A combination of FDG-PET and CT scanning characteristics seems promising, and integrated PET/ CT is becoming more widely available, although the exact clinical value and efficacy is not yet fully established. In addition, assessment of these modalities in joint reading sessions with radiologist, nuclear medicine physician, medical and surgical oncologists significantly impacts upon patient management. This review evaluates the potential of FDG-PET and combined PET/CT in patients with colorectal liver metastases and discusses potential future possibilities.

Added value of positron emission tomography imaging in the surgical treatment of colorectal liver metastases

Objective[F-18]-Fluorodeoxyglucose-positron emission tomography (FDG-PET) is used increasingly in the work-up to surgery for patients with potentially resectable colorectal liver metastases. This study evaluates the clinical effectiveness, impact on health care resources and cost-effectiveness of adding FDG-PET to the diagnostic algorithm alongside a randomized clinical trial from a health care perspective. MethodsIn a randomized clinical trial, the net monetary benefit (NMB) of FDG-PET added to conventional diagnostic work-up (CWU) was determined in patients with colorectal liver metastases. Seventy-five patients were included in each arm. Change in clinical management, futile laparotomies, preoperative findings and all relevant health care consumption were prospectively documented during 3 years. To assess health-related quality of life European Quality of Life-5 Dimensions was administered at the time of randomization, 3 and 6 weeks postoperatively, and every 3 months postoperatively for 3 years. Quality-adjusted life years (QALYs) were calculated based on European Quality of Life-5 Dimensions outcomes. ResultsIn adding FDG-PET, diagnostic performance increased and futile laparotomies were reduced by 38%. Both health-related quality of life and QALYs showed no significant difference between the CWU and PET groups. For CWU and PET groups costs were &OV0556;92 836 and &OV0556;81 776, respectively, accumulated in 3 years after randomization. NMB ranged from &OV0556;1004 to &OV0556;11 060 depending on the monetary value given to a QALY. When costs for chemotherapy were disregarded, costs amounted to &OV0556;15 874 for CWU and &OV0556;18 664 for PET group. ConclusionAdditional costs of FDG-PET in the diagnostic work-up of patients with potentially resectable colorectal liver metastases were compensated by a reduction in futile laparotomies. The NMB analysis showed savings over a relevant range of willingness to pay for a QALY.

Colorectal cancer: the role of PET/CT in recurrence.

Many imaging modalities and scanning techniques, such as contrast enhanced CT, MRI and FDG-PET, are available for assessment of recurrent colorectal carcinoma. In addition, integrated PET/CT is becoming increasingly available. Intuitively, a synergistic combination of scanning characteristics sounds promising. However, the exact clinical value has not yet been fully established. The role of PET/CT image fusion must be weighed carefully against other available modalities. In this review we evaluate the potential of combined PET/CT in recurrent colorectal carcinoma. When available, PET/CT currently appears the diagnostic tool of choice. In the near future, combined PET/MRI may further enhance the diagnostic algorithm.

Role of FDG-PET in the diagnosis and treatment of colorectal liver metastases.

Positron emission tomography (PET) using [18F]-2-deoxy-2-fluoro-d-glucose (FDG) has emerged as a promising diagnostic modality in recurrent colorectal cancer. Data in the literature show that the addition of FDG-PET changes disease management in up to 30% of patients with potentially resectable liver metastases, mainly by detecting previously unknown extrahepatic disease. Furthermore, FDG-PET is useful in the follow-up of patients who underwent surgical procedures of the liver, since it is exquisitely sensitive in detecting residual or relapse malignancy in scarred liver tissue following both resection and local ablative techniques. For follow-up during systemic therapy, early FDG-PET appears predictive for response to therapy. However, at present, the available data are insufficient to justify the FDG-PET-driven management of patients treated with chemotherapy. FDG-PET and computerized tomography are complimentary techniques in staging and restaging patients with advanced colorectal cancer. The combination of these two modalities significantly impacts upon patient management.

Contents Vol. 25, 2008

N. Ando, Chiba C.G.M.I. Baeten, Maastricht C. Bassi, Verona H.-P. Bruch, Lübeck X.P. Chen, Wuhan S.-T. Fan, Hong Kong A. Fingerhut, Poissy S. Galandiuk, Louisville, Ky. H.G. Gooszen, Utrecht T.M. van Gulik, Amsterdam J.G. Hunter, Portland, Oreg. I. Ihse, Lund J.R. Izbicki, Hamburg J.F. Ji, Beijing M. Kaminishi, Tokyo M.R.B. Keighley, Birmingham J.-P. Kim, Seoul J.J.B. van Lanschot, Rotterdam R.S. Leicester, London H. Lippert, Magdeburg P. Malfertheiner, Magdeburg P.E. O’Brien, Prahran R. Padbury, Adelaide H.A. Pitt, Indianapolis, Ind. L.F. Rikkers, Madison, Wisc. F. Seow-Choen, Singapore J.R. Siewert, Munich M. Sunamura, Sendai Y. Tekant, Istanbul H.W. Tilanus, Rotterdam J. Toouli, Adelaide B. Vollmar, Rostock A.L. Warshaw, Boston, Mass. Official Journal of European Digestive Surgery (EDS)