Optimal anatomic coverage for CT in staging lung cancer: lessons from PET-CT correlation

Objective

To determine the optimal anatomic coverage at CT that would provide the most accurate staging for patients with non-small cell lung cancer.

Methods

We reviewed lung cancer staging PET-CT scans and correlated them with staging chest CT scans performed within 50 days of the PET-CT study. There were 113 patients who underwent both studies within our time frame. We reviewed the results of subsequent imaging studies and surgical and biopsy procedures to determine the final stage for each patient. This study was approved by the local institutional review board.

Results

In 86 (76%) of 113 patients, staging by PET-CT and by CT from the lung apices through the lung bases was identical. PET-CT upstaged 21 patients (19%) compared with CT findings; in 13 of these patients the PET-CT noted disease that was either outside of the anatomic range of any lung cancer staging CT or was within the area scanned by CT, but was not evident by CT. In the other 8 upstaged patients, extending the anatomic scope of the CT scan to the supraclavicular region (5), adrenal glands (2) or abdomen (1) would have resulted in correct staging.

Conclusions

CT scanning from the supraclavicular region through the caudal adrenal glands improves the accuracy of CT staging of lung cancer compared with scanning from the lung apices through the lung bases. Anatomic coverage beyond the adrenal glands has a low yield for improved staging, at the cost of requiring administration of oral contrast to all patients.

Summary

To determine the optimal anatomic coverage at CT that would provide the most accurate staging for patients with non-small cell lung cancer, we reviewed lung cancer staging PET-CT scans and correlated them with staging chest CT scans performed within 50 days of the PET-CT study. CT scanning from the supraclavicular region through the caudal adrenal glands improves the accuracy of CT staging of lung cancer compared with scanning from the lung apices through the lung bases. Anatomic coverage beyond the adrenal glands has a low yield for improved staging, at the cost of requiring administration of oral contrast to all patients undergoing lung cancer staging.