Introduction The advent of CT scanning as a routine test in the work-up of pulmonary disease has brought with it the unexpected detection of large numbers of pulmonary nodules, most of which are of a benign aetiology, even in high risk groups. Previous lung cancer screening studies have shown that likelihood of malignancy in nodules < 7 mm in size is < 1% in patients. Current guidance for the follow-up of these patients bases repeat CT scanning on nodule size and the risk of malignancy (Fleischner Society 2005; figure 1). However, such surveillance comes with increased healthcare costs, patient anxiety and radiation exposure. To look at this further, we reviewed the burden of repeat scanning on the healthcare economy.
Methods Two trained readers independently reviewed 100 randomly selected CT thorax scans from individual patients (mean age 63 years [SD 15]) and noted the number, size and characteristics of any nodules present. Economic analysis was based on costs of CT scan (low dose CT = £115) and the number of additional follow-up CT scans required.
Results Overall, 249 nodules were detected in 86 patients; 9 with a solitary calcified nodule were excluded. Of the remainder, 22 (28%) had nodule (s) < 4 mm, 28 (36%) 4 6 mm, 13 (17%) 6 8 mm and 21 (27%) >8mm. Assuming that all patients were high risk, based on Fleischner guidelines the total number of CT scans required over 2 years would be 15 (<4 mm), 56 (4 6 mm) and 39 (6 8 mm) at a cost of £1725, £6440 and £4485 respectively.
Discussion Over three quarters of our patients in this random sample had significant incidental pulmonary nodules, and their surveillance according to current guidelines would result in a significant burden to the healthcare system, not only in terms of cost but also through increased clinician time and patient anxiety. New protocols for the follow up of these low-risk patients are required if the healthcare economy is to cope with this increasing surveillance burden.