Introduction Current NICE guidance indicates that lung cancer should be staged by a contrast enhanced chest CT scan which includes the liver and adrenals, and to look for distant metastases those with potentially curable disease should be offered PET-CT scanning. However, the latter is expensive and limited in availability, and it has been suggested that including the pelvic area in the staging CT scan might obviate the need (Botchua et al 2012). We looked at 284 PET-CT scans performed for the staging of lung cancer in our unit to test this further.
Method We selected all PET-CT scans that showed distant metastases (and therefore upstaged the disease) for further scrutiny. In those where pelvic deposits were visible on the PET component, the CT element was reviewed to establish whether the diagnosis of pelvic metastases could have been made by CT scan alone.
Results 23 PET-CT scans (8.1%) identified distant metastatic disease, in 3 (1.1%) cases in the pelvic area. Of these, 2 had bony metastases that were visible on the CT element of the scan: in the remaining case the PET element demonstrated increased uptake around a joint replacement and CT component demonstrated a pathological fracture.
Conclusion This study has shown that if the pelvic area was included in the CT staging scan for lung cancer, in our cohort of 284 patients, only 3 (1.1%) would not have required a subsequent PET scan. In the remaining patients, the additional burden of pelvic CT in terms of radiation exposure and financial expense cannot be justified and therefore we do not recommend that the protocol for a staging CT scan in lung cancer is altered to include the pelvis.