A systematic review on the role of FDG-PET/CT in tumour delineation and radiotherapy planning in patients with esophageal cancer.
OBJECTIVE
FDG-PET/CT has proven to be useful in the staging process of esophageal tumours. This review analysed the role of FDG-PET/CT in tumour delineation and radiotherapy planning in comparison with CT alone among patients with esophageal cancer. Thereby we focused on the detection of the primary tumour and lymph nodes by FDG-PET/CT, changes in target volume (TV) delineation based on FDG-PET/CT and its validity, changes in inter- and intra-observer variability in TV delineation, consequences for radiotherapy treatment planning with regard to either target volumes or organs at risk and finally on the validation of FDG-PET/CT-based TVs in terms of treatment outcome.


METHODS
A literature search was performed in MEDLINE and Cochrane library databases for studies concerning the current value of FDG-PET/CT in tumour detection and delineation and radiotherapy-planning procedures among patients with esophageal cancer. Both prospective and retrospective studies were included.


RESULTS
Fifty publications met the eligibility criteria, of which 19 were review papers and one was a case report. The remaining 30 publications reported on the results of original studies. FDG-PET was able to identify most primary tumours, with a sensitivity and specificity for the detection of metastatic lymph nodes of 30-93% and 79-100%. The use of FDG-PET/CT resulted in changes of target volumes, and consequently in changes in treatment planning. However, evidence supporting the validity of the use of FDG-PET/CT in the tumour delineation process is very limited. Only three studies reported a significant positive correlation between FDG-PET-based tumour lengths and pathological findings. There were two studies that tested the influence of FDG-PET/CT to the inter- and intra-observer variability. One of them found a significant decrease in inter- and intra-observer variability, while the others did not. Furthermore, there are no studies demonstrating the use of PET/CT in terms of improved locoregional control or survival.


CONCLUSIONS
Since the literature is very limited standard implementation of FDG-PET/CT into the tumour delineation process for radiation treatment seems unjustified and needs further clinical validation first.
Muijs
Christina T
CT
Department of Radiation Oncology, University of Groningen, Groningen, The Netherlands. c.t.muijs@rt.umcg.nl
Beukema
Jannet C
JC
Pruim
Jan
J
Mul
Veronique E
VE
Groen
Henk
H
Plukker
John Th
JT
Langendijk
Johannes A
JA
D004938:Esophageal Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy*; D019788:Fluorodeoxyglucose F18; D006801:Humans; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011880:Radiotherapy Planning, Computer-Assisted; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D019788:Fluorodeoxyglucose F18