Introduction and objectives FDG PET-CT scans are a valuable tool in the diagnosis and staging of lung cancer, but their growing use in other diseases can cause resource issues, and in some cases they may be ordered by non-specialists further congesting the patient pathway. To study this further, we looked at referral patterns for PET-CT scans in the diagnosis of lung cancer at our hospital, paying particular attention to the reason for the scan and the referring clinician.
Methods A retrospective audit was undertaken of all PET-CT scans performed for the investigation of suspected lung cancer in 2014 by the Liverpool Lung Cancer Unit (LLCN). The LLCN consists of Liverpool Heart and Chest Hospital, a specialist cardiothoracic centre in the North West of England and the Royal Liverpool University Hospital, a teaching hospital.
Results All 253 PET-CT scans (186 for outpatients) carried out during 2014 for the investigation of suspected lung cancer were reviewed. One hundred and seventy five (69%) found malignancy. Scans ordered by lung cancer specialists were more likely to demonstrate a cancer diagnosis (145 cancer versus 52 benign) compared to those requested by non-specialists (30 cancer versus 26 benign), (Chi2 = 8.21, P < 0.01) (Figure 1).
The commonest causes for a negative scan result were mass 27 (34%), nodule follow up 17 (22%) and new nodule assessment 14 (18%) respectively. Of 31 patients (39%) who had a PET-CT scan for nodule assessment, 8 (26%) were <10 mm in diameter. Overall, 22% of all negative scans were for nodule surveillance.
Conclusions We have shown that scans arranged by lung cancer specialists are more likely to give a positive yield, and also that the guidance for their use in nodule investigation is not being strictly followed. The results indicate that there is a need for better guidelines and patient pathways to ensure the most appropriate use of expensive resources.