Clinical impact of FDG PET-CT in patients with potentially operable metastatic colorectal cancer
Introduction
Colorectal cancer (CRC) remains one of the most common malignancies in the UK, accounting for approximately 21,000 cases annually in men and 17,000 in women.1, 2, 3 Long-term patient outcome is heavily influenced by the initial stage of disease. Between 25–30% of patients have hepatic metastases at presentation, and recurrent disease is seen in up to 30% of patients within 2 years of initial resection, which in the majority manifests as liver metastases.4, 5 Surgical resection of limited metastatic disease with curative intent is a well-established treatment strategy, with recent meta-analyses demonstrating favourable long-term outcomes.6, 7, 8, 9, 10, 11 At least 17% of patients have a ≥10 year disease-free survival after liver metastatectomy, with a 5 year survival of 26–50%.6, 7, 8, 9, 10 Five-year survival of up to 64% has also been demonstrated following resection of pulmonary metastases.11 Appropriate patient selection is crucial; historically, up to 50% of patients with disease apparently limited to the liver on conventional imaging had inoperable findings at laparotomy.12 The prevalence of unexpected extra-hepatic disease at liver surgery is now around 5–10% largely due to improvements in cross-sectional imaging technology over the past couple of decades. Although the presence of extrahepatic disease has been shown to increase mortality and has traditionally been taken as a contraindication to resection of liver metastases,13 this no longer represents an absolute contraindication to surgery, but necessitates a wider operative field or second operation, if technically feasible, to allow a truly curative surgical resection.6, 14 Five-year survival of 29% following complete resection of both simultaneous intra- and extrahepatic metastases has been reported.15
Over the past decade 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography–computed tomography (PET-CT) has been established as a major component in the management of cancer patients.16 The optimal role of FDG PET-CT in patients with CRC has not yet been fully defined. In 2004 the National Institute for Health and Clinical Excellence (NICE) included a review of the available literature in their document Improving outcomes in colorectal cancer, suggesting that PET-CT was most useful in the detection of disease recurrence.17 One of the more compelling indications for FDG PET-CT is in CRC patients being considered for metastatectomy, in order to avoid inappropriate major surgery in patients with undetected nodal or distant metastatic disease. The aim of the present study was to analyse the clinical impact on patient management of introducing FDG PET-CT into the preoperative work-up of patients with potentially resectable metastatic CRC in a large-volume tertiary-referral centre.
Section snippets
Patients
Data were collected retrospectively over an 18-month period (November 2007 to March 2009). Following consultation with the Chairman of our institutional ethics committee, full ethics review board submission and approval was not required for the study. A search was performed on the institutional radiology information system (CRIS™, Healthcare Software Systems, Banbury, UK). Consecutive data collection identified 112 patients with histologically proven colorectal adenocarcinoma who underwent FDG
Results
A total of 102 patients remained after exclusions. The mean patient age was 67 years (range 27–85 years) with a male to female ratio of 4:3. The group consisted of 94 (93%) patients with known colorectal liver metastases, five (5%) with isolated lung metastases, and three (3%) with intra-abdominal deposits all under consideration for curative resection. Within the study group, 17 (17%) patients had undergone prior surgical resection for either liver (n = 14), lung (n = 1), or both liver and lung (n =
Discussion
The present study investigated the role of PET-CT in the preoperative work-up of patients with metastatic CRC under consideration for curative resection. The majority of patients had liver metastases (93%), with lung and peritoneal deposits accounting for the remainder. PET-CT was concordant with conventional imaging findings in 65 (64%) patients. This concurs with other studies in similar patient groups with concordance rates between PET-CT and conventional imaging most commonly quoted between
References (47)
- et al.
Liver resection for metastatic colorectal cancer in the presence of extrahepatic disease
Lancet Oncol
(2009) - et al.
Impact of prognostic factors on clinical outcome after resection of colorectal pulmonary metastases
Clin Colorectal Cancer
(2006) - et al.
A critical review of the major indicators of prognosis after resection of hepatic metastases from colorectal carcinoma
Surg Oncol Clin N Am
(2003) - et al.
FDG-PET for the pre-operative evaluation of colorectal liver metastases
Eur J Surg Oncol
(2004) - et al.
Accuracy and cost-effectiveness of [18F]-2-fluoro-deoxy-D-glucose-positron emission tomography scan in potentially resectable non-small cell lung cancer
Chest
(2004) - et al.
Cost-effectiveness of PET imaging in clinical oncology
Nucl Med Biol
(1996) - et al.
Physiology and pathophysiology of incidental findings detected on FDG-PET scintigraphy
Semin Nucl Med
(2010) - Cancer research UK. UK bowel cancer statistics. Available at http://info.cancerresearchuk.org/cancerstats/types/bowel....
Cancer statistics registrations: registrations of cancer diagnosed in 2007
(2008)Cancer stats 2007
(2007)