Positron emission tomography-computed tomography for postoperative surveillance in non-small cell lung cancer

Background: The role of positron emission tomography-computed tomography (PET-CT) for the staging of non-small cell lung cancer (NSCLC) has been well documented, whereas its role for postoperative surveillance after the curative resection of this cancer has not. We prospectively implemented PET-CT in our surveillance protocol for recurrence of NSCLC and investigated its effectiveness as compared with that of conventional methods.

Methods: The cohort for our study of PET-CT in detecting recurrence of NSCLC consisted of 358 patients who had undergone complete resection of NSCLC between January 2005 and June 2008. After resection of their tumors, all of the patients were routinely examined at the thoracic surgical outpatient clinic at 3-month intervals for 2 years and after this at 6 month intervals for next 3 years. Careful patient interviews, physical examinations, chest roentgenography, and measurements of the serum carcinoembryonic antigen level were done at each visit. Contrast-enhanced chest CT was done at 6-month intervals, and PET-CT was done annually for 5 years after resection of NSCLC.

Results: Recurrences were detected in 111 patients (31%). In 60 of these patients, recurrence was detected with conventional methods, and in the remaining 51 patients recurrences were detected with simultaneous PET-CT and chest CT. Among these latter patients, recurrence was evident in both the chest CT and PET-CT scans of 26 patients (51.0%), and in the PET-CT scans alone of 19 patients (37.3%). Five lung lesions (2 small, 1 subpleural, 1 cavitary, and 1 nodule of ground-glass opacity) and 1 pancreatic metastasis were detected with chest CT only.

Conclusions: When the two methods were used simultaneously, PET-CT seemed superior to chest CT for detecting recurrences of NSCLC. However, because PET-CT may fail to detect small or hypometabolic recurrences of NSCLC, we recommend that it be done on an annual basis along with low-dose chest CT.