Table 4. Radiology related issues for ADC-based treatment in patients with locally unresectable or metastatic bladder cancer.
| Clinical questions | What radiologists need to know |
|---|---|
| Which imaging modalities should be primarily ordered for screening or baseline imaging before ADC-based treatment? | - In the NCCN guidelines, both CT and MRI are recommended for evaluating primary bladder cancer and metastatic disease |
| - Chest/abdomen/pelvis CT remains a key modality, and if a more detailed evaluation of bladder cancer is needed, either CT abdomen/pelvis using a CT urography protocol can be utilized | |
| - FDG-PET/CT is also recommended (category 2B) | |
| Which imaging modalities should be performed for patients with suspected bone or brain metastasis? | The NCCN guidelines recommend FDG-PET/CT or bone scan for bone metastasis, and brain MRI without/with contrast for brain metastasis in both screening and follow-up (category 2B) |
| Which response criteria should be used for clinical trial? | RECIST 1.1 is enough, as pseudoprogression has been reported very rarely in urothelial carcinoma |
| How to differentiate CR and PR on imaging? | CR rate is a critical endpoint in some clinical trial. When primary bladder cancer is resolved, remaining scar tissue may hamper to determine CR. Multiparametric MRI might be helpful. For example, dense T2 hypointensity without diffusion restriction of the bladder lesion may represent CR |
| How can we diagnose pneumonitis on CT? | Pneumonitis can be detected and classified on CT according to ATS/ERS classification. The most common pattern of EV or SG-related pneumonitis is organizing pneumonia. Frequently, clinical correlation is required to differentiate drug-related pneumonitis and infectious pneumonia |
| How can we use CT for gastrointestinal toxicity? | When patients show severe diarrhea along with abdominal pain and laboratory abnormalities, abdominal CT can be used to evaluate any superimposed enterocolitis |
ADC = antibody-drug conjugate, NCCN = National Comprehensive Cancer Network, CT = computed tomography, MRI = magnetic resonance imaging, FDG = fluorodeoxyglucose, PET = positron emission tomography, RECIST = Response Evaluation Criteria in Solid Tumors, CR = complete response, PR = partial response, ATS/ERS = American Thoracic Society/European Respiratory Society, EV = enfortumab vedotin, SG = sacituzumab govitecan