Impact of integrated PET/CT in the staging of oesophageal cancer—a UK population-based cohort study
Introduction
The incidence of oesophageal carcinoma has dramatically increased over the last two decades1, 2, 3 and the prognosis remains poor, with an overall 5-year survival rate of 7%. Oesophagectomy is generally recognized as offering the best prospect of long-term cure, but is a major procedure with perioperative mortality in modern series of 2–10% and significant morbidity in up to 60% of patients.4 Postoperative quality of life is significantly compromised for 3–6 months and never returns in those who develop early postoperative recurrence or metastatic disease.5 Poor long-term survival for patients who appear to have complete tumour resection appears to be, in part, due to a failure to detect distant metastases at or before the time of surgery.6, 7 Accurate preoperative staging is thus essential in providing informed treatment choices for these patients.
Conventional imaging used for staging oesophageal cancer in the UK includes contrast-enhanced computed tomography (CT) of the chest and abdomen with positive or negative oral contrast medium load, and endoscopic ultrasound (EUS), techniques that provide high-quality anatomical information. EUS enables accurate assessment of the depth of invasion (T stage) together with accurate information regarding local nodal involvement (N stage). Recently preoperative imaging has variably included the use of integrated positron-emission tomography and CT (PET/CT). PET detects metabolically active tissue based on the metabolism of glucose.8 Studies have reported that metastases missed at CT were subsequently identified using PET in more than 10% of patients with oesophageal cancer.9, 10, 11 Combined PET/CT imaging facilitates the separation of normal physiological uptake from pathological uptake, and enables accurate anatomical localization of functional abnormalities. PET/CT combines both multisection CT and PET capabilities in two sequential scans, avoiding the need for patient motion between the CT and PET components of the study, thereby leading to more accurate co-registration of the CT and PET data.12 The use of PET/CT is likely to add accuracy over PET alone by enabling morphological and metabolic information to be gained in one sitting allowing more precise interpretation. Use of PET/CT in routine clinical practice in the UK has been variable and dependent largely on availability of this imaging technique.
The aim of this study was to establish the effect of combined PET/CT on the management of a prospective cohort of patients with newly diagnosed oesophageal cancer across five cancer networks in England.
Section snippets
Materials and methods
A multicentre prospective study was undertaken of patients with newly diagnosed oesophageal cancer who underwent PET/CT imaging. This study was supported and sponsored by the upper GI tumour panel of the South West Cancer Intelligence Service (SWCIS), a cancer registry encompassing a population of 6.6 million, across five cancer networks covering the south and southwest of England. The study included patients from 12 NHS trusts. Ethical approval was not required for this study as this was an
Results
A total of 191 (149 male, 42 female) patients of median age 66 years underwent PET/CT (Table 1). The findings of the PET/CT examinations are summarized in Fig. 1 indicating the distribution of PET/CT examinations that were positive and negative. True-positive results were those that identified metastases and synchronous pathology not detected by CT and EUS, in contrast to false-positive results that were later shown to have incorrectly suggested the presence of metastases not detected by CT and
Discussion
This is the first UK multicentre study to review the impact of PET/CT on patients thought to be candidates for curative treatment based on CT/EUS. PET/CT suggested distant metastases in 16% of patients and these metastases were confirmed in 9%. This is consistent with previous single-centre series where 10% or more of patients have been found to have previously unsuspected metastatic disease in oesophageal cancer after PET/CT.14, 15, 16 As well as contributing to pre-treatment staging,
References (26)
- et al.
Positron emission tomography with F-18-fluorodeoxyglucose in a combined staging strategy for esophageal cancer prevents unnecessary surgical explorations
J Gastrointest Surg
(2005) - et al.
Impact of the introduction of integrated PET-CT into the preoperative staging pathway of patients with potentially operable oesophageal carcinoma
Clin Radiol
(2008) - et al.
Integrated CT-PET imaging of esophageal cancer: unexpected and unusual distribution of distant organ metastases
Curr Probl Diagn Radiol
(2007) - et al.
Trends in oesophageal cancer incidence and mortality in Europe
Int J Cancer
(2008) Oesophago-gastric adenocarcinoma—an epidemiological perspective
Aliment Pharmacol Ther
(2004)Registrations of cancer diagnosed in 1993–96, England and Wales
Health Stat Q
(1999)- et al.
Preoperative risk analysis and postoperative mortality of oesophagectomy for resectable oesophageal cancer
Br J Surg
(1998) - et al.
A prospective longitudinal study examining the quality of life of patients with esophageal carcinoma
Cancer
(2000) - et al.
Cancer of the esophagus
- et al.
Autopsy findings in squamous-cell carcinoma of the esophagus
Cancer
(1982)