M18 Impact of incidental findings on PET-CTs performed as part of the lung cancer pathway at a district general hospital

Abstract

PET-CT is embedded into the lung cancer pathway; NICE recommends performing it in all suitable for treatment with curative intent. It can also be useful in the assessment of solitary pulmonary nodules. Scanning the whole body with this functional form of imaging inherently picks up incidental findings. This study was designed to determine the frequency of these, ascertain the subsequent management required and the potential impact this could have on the patient. During 2016, 128 patients had PET-CT’s performed as part of the lung cancer pathway. These records were reviewed, focussing on diagnosis, investigation and management. Of the 128 scans performed, 52 incidental findings were noted in 42 patients (32.8%) with varied organ involvement (see figure 1). A majority (23/42, 54.7%) of these patients had a final diagnosis of lung cancer. Just over half (28/52, 53.8%) of the incidental findings were further investigated; 67 subsequent tests, alternative MDT discussions or clinic reviews were performed (mean 2.4 per incidental finding). Of those investigated, a quarter (7/28, 25.0%) were diagnosed with a malignancy of non-lung origin (breast (3), prostate, thyroid, hepatobiliary and ovarian), and 2 (7.1%) with pre-malignant features requiring surveillance. The rest included 15 (54.6%) diverse benign conditions such as gastritis, goitre, and an ovarian cyst. Five (14.2%) were false positives (3 ENT, 1 thyroid, 1 gastrointestinal). This study discovered a high rate of incidental findings on PET-CT. There were higher rates of incidental malignancy or pre-malignancy compared to previous studies (32.1% vs 4.2%1 and 3.4%2). This may suggest that only relevant or worrying incidental findings were investigated or that more effort should have been made to further investigate incidental findings. The study highlights the need to counsel patients appropriately about the possibility of incidental findings and the ensuing burden of further tests or hospital attendances when discussing PET-CT. References Chopra A, et al. Incidental findings on positron emission tomography/CT scans performed in the investigation of lung cancer. Br J Radiol2012;85:229. Edwards G, et al. Incidental findings on PET-CT scans; how they are managed and how they impact on the lung cancer pathway. ERJ2014;44:346.