Source: Lancet  |  Posted 8 years ago

Early lung cancer can be detected effectively using low-dose spiral computed tomography (CT) combined with selective use of positron emission tomography (PET), report researchers.

Late diagnosis of extensive lung cancer is strongly associated with treatment failure. While spiral CT has been demonstrated to effectively detect early-stage lung cancer in high-risk individuals, questions have been raised concerning the high frequency of false-positive nodules and issues associated with differential diagnosis.

In a prospective demonstration study, Ugo Pastorino, M.D., of the Istituto Nazionale Rumori in Milan, Italy, and colleagues investigated the efficacy of annual spiral CT selectively coupled with PET to improve CT accuracy.

The study population consisted of 1035 individuals, aged 50 years or older, having a minimum of 20 pack-years smoking history and no previous malignancy. All patients received a yearly assessment with low-dose CT, with or without PET, for 5 years.

Additional investigation with high-resolution CT was performed for lesions < 5 mm in size, after which PET was used to perform further investigation for non-calcified lesions < 7mm.

Within 2 years, 440 non-calcified lung lesions were identified and 22 cases of lung cancer were diagnosed. The mean time to diagnosis was 115 days at baseline, and 64 days at the 2-year repeat scan.

Six patients underwent surgical biopsy for benign disease due to false-positive results. No interval lung cancers occurred during 2.5 years of active follow up, and 21 (95%) of the lung cancer patients were alive at study end.

"We found selective use of PET scan to be helpful in replacing fine-needle aspiration biopsy for differential diagnosis," the researchers said. "Combined with a simplified algorithm for CT assessment, PET enabled us to complete the diagnostic work up within an average time of 3.8 months at baseline and 2.1 months at year 2, thereby reducing the anxiety related to the diagnostic phase."