Aims and objectives
The West of Scotland has one of the highest rates of lung cancer incidence and mortality in the world.
As per SIGN guidelines [1],
all patients with suspected lung cancer should undergo a contrast-enhanced CT scan of the chest and abdomen.
Following this,
FDG PET-CT is performed to futher characterise pulmonary lesions and stage lung cancer identified on CT prior to treatment.
AIMS:
(1) To investigate the frequency and subtype of unsuspected distant metastases on PET-CT that were undetected on prior CT scan.
(2) To...
Methods and materials
Retrospective review of 2631 patients who underwent PET-CT at the West of Scotland PET Centre for characterisation of indeterminate lung nodules and staging of primary lung cancer from January 2016-December 2017.
Re-staging lung cancer patients were excluded.
Patients with FDG-avid distant metastatic disease (M1) were identified and the prior contrast-enhanced CT scan was reviewed for each case.
FDG-avid distant metastases that were CT-occult,
outwith the CT field-of-view (FOV) or progressive disease (new in the interval and visible on the CT component of the PET-CT) were...
Results
74% of cases were biopsy-proven NSCLC,
15% SCLC and 11% unknown.
49% of patients had prior CT chest and abdomen,
31% CT chest,
abdomen and pelvis and 20% CT chest. PET-CT was performed mean 26 days following the initial CT.
8% (197/2631) patients had FDG-avid distant metastases (F51: M49%; mean age 68 years).
Of these patients,
66% (130/197) had unsuspected M1 disease not identified on their initial CT at single (70%) or multi-sites (30%).
A striking 81% of PET-positive bone metastases were undetected on previous...
Conclusion
In this high risk population,
8% of lung cancer patients had FDG-avid distant metastases on PET-CT. Of these patients,
66% had M1 disease that was unsuspected on prior contrast-enhanced CT.
A striking 81% of PET-positive bone and 67% of liver metastases were undetected on previous CT.
A large proportion of uncommon M1 disease sites,
notably soft tissue,
pancreatic and distant nodal metastases were undetected on previous CT.
PET-CT is essential for accurate staging and treatment planning in lung cancer patients.
References
[1]Scottish Intercollegiate Guidelines Network.
SIGN 137 - Management of Lung Cancer. Edinburgh: SIGN 2014.