Reply by Authors

Bladder cancer is one of the costliest cancers and understanding the nuances of appropriate imaging is necessary in our stewardship of limited health care resources. Our study demonstrates that the routine patient undergoing radical cystectomy is unlikely to benefit from 18F-FDG PET/CT (PET/CT) for lymph node staging over conventional imaging. The best data for PET/CT are in the setting of sus- pected metastatic disease where the PET avidity of a CT visible lesion can provide clarity as to the na- ture of this lesion. A prior study from Memorial Sloan Kettering Cancer Center supported the utility of PET/CT in the metastatic setting due to its excellent diagnostic properties and clinical utility in guiding further therapy (reference 4 in article). Corroborating this, surveys showed that clinicians changed their planned management in 68% of cases based on the PET/CT findings. Our study emphasizes that advances in muscle invasive bladder cancer imaging need to focus on improving sensitivity for small lymph node metas- tases. This will be accomplished by either improving the scanner or the imaging agent. Digital PET/CT has shown some promise in improving PET/CT resolution.1 Additionally, advances in urothelial carcinoma therapeutics targeting specific molecular alterations like FGFR-3 and Nectin-4 support the possibility of targeted urothelial carcinoma molec- ular imaging,2,3 a concept which has become stan- dard in prostate cancer treatment. Shifting away from the nuclear medicine approach, other imaging modalities such as ultrasmall paramagnetic iron oxide particles and magnetic resonance imaging have been previously shown to improve detection of metastasis and may also leverage magnetic reso- nance imaging for local tumor staging.4 Our study reminds us that it will be essential that novel im- aging modalities demonstrate a clear improvement over our current standard before they are widely adopted.