Lung cancer causes more deaths-around 1.3 million worldwide annually-than any other cancer; five-year survival is only around 10% in Europe due to late disease detection. Low-dose spiral CT of the chest effectively detects early-stage lung cancer in high-risk individuals; however the high detection of benign lesions has hampered the introduction of large-scale screening programmes.
Ugo Pastorino from the National Institute of Cancer, Milan, Italy, Peter Boyle from the European Institute of Oncology, Milan, Italy, and colleagues investigated the efficacy of repeated yearly spiral CT and selective use of PET (to increase the accuracy of CT) in a large population of high-risk volunteers. Over 1000 heavy smokers (minimum consumption 26 cigarettes a day for 37 years) aged 50 years or older underwent annual low-dose spiral CT, with or without PET, for 5 years. Lesions up to 5 mm were deemed non-suspicious and low-dose spiral CT was repeated after 12 months (year 2).
By the second year of assessment, 22 cases of lung cancer had been diagnosed (11 at baseline, 11 at year 2). 440 lung lesions were identified in 298 (29%) participants, and 95 were recalled for high-resolution contrast CT. PET scans were positive in 18 of 20 of the indentified cancer cases. Removal of malignant tissue was achieved in 95% of lung cancers.
Ugo Pastorino comments: "We have shown that low-dose spiral CT combined with selective use of PET can effectively detect early lung cancer. A more conservative approach to very small CT-detected nodules is justified, and lesions up to 5 mm can be followed up at 12 months without major risks of progression. Although prospective randomised trials are the proper instrument with which to measure the ultimate outcome of any screening policy, pilot studies addressing specific technical issues and methods are of fundamental importance in a phase of accelerated development of imaging and molecular technology, to design the optimum protocol to be tested in large-scale trials."
In an accompanying Commentary (p 588), Stefan Diederich from Marien-Hospital, Düsseldorf, Germany, concludes: "The study by Pastorino and colleagues adds an important aspect to the field of lung cancer screening with low-dose computed tomography - ie, simplification of the diagnostic algorithm for nodule classification. More data are required to define the ideal algorithm.
Furthermore, prospective randomised trials are underway to analyse whether regular low-dose computed tomography can, in fact, reduce mortality from lung cancer."
Contact: Dr. Ugo Pastorino, Istituto Nazionale Per lo Studio e la Cura Dei Tumori,Via G Venezian 1, 20133 Milan, Italy; T) (mobile phone, preferably after 8pm European time) 39-348-018- 5756; E) Ugo.Pastorino@istutotumori.mi.it.
Dr. Stefan Diederich, Department of Diagnostic and Interventional Radiology, Marien Hospital, Academic Teaching Hospital, Rochusstraße 2, D - 40479, Düsseldorf, Germany; T) 49-211-4400-2101; F) 49-21-4400-2102; E) s.diederich@marien-hospital.de.
Journal
The Lancet