Elsevier

Clinical Radiology

Volume 64, Issue 7, July 2009, Pages 699-705
Clinical Radiology

Impact of integrated PET/CT in the staging of oesophageal cancer—a UK population-based cohort study

https://doi.org/10.1016/j.crad.2009.03.003Get rights and content

Aim

To document the impact of integrated positron-emission tomography and computed tomography (PET/CT) on the management of a cohort of UK patients undergoing PET/CT as part of their staging investigations for potentially curable oesophageal cancer.

Materials and methods

A multicentre, prospective study of newly diagnosed patients with oesophageal cancer undergoing PET/CT was set up across five cancer networks covering a total population of 6.6 million. Data were prospectively collected for cases diagnosed between 1 November 2006 and 31 October 2007.

Results

One hundred and ninety-one patients underwent PET/CT, with 31 (16%) positive for possible metastatic disease. Amongst the 31 positive examinations, 18 (9.4%) were confirmed to have metastatic disease, and 13 (6.5%) patients had no subsequent evidence of metastatic disease, although in three (1.6%) of these a second previously unsuspected pathology was diagnosed. Two patients had false-negative PET/CT and were found to have metastatic disease. The results of the PET/CT examination down-staged 10 (5%) patients thought to have coeliac/M1a node involvement on CT. Fifteen of 110 (13%) patients with stage 3 or 4 disease at CT and endoscopic ultrasound (EUS) had confirmed metastatic disease at PET/CT, compared with none of 18 with stage 2b, three of 52 (6%) with stage 2a, and none of 10 with stage 1 disease.

Conclusion

This study confirms the role of PET/CT in a multicentre UK setting in the management of patients with potentially curable carcinoma of the oesophagus, improving the accuracy of pre-treatment staging compared with CT and EUS alone. Early tumours infrequently show evidence of metastasis on PET/CT, although further data are required to confidently determine the stage of tumours where PET/CT has no additional value.

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,

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