Downstream Studies Following the Use of Bone Scan in the Staging of Muscle-invasive Bladder Cancer

Abstract

ObjectiveTo quantify the use of downstream studies following staging bone scans in patients with muscle-invasive bladder cancer. Bone scans may be obtained in high-risk bladder cancer patients prior to radical cystectomy to exclude bone metastases. However, false-positive bone scans can occur, resulting in the need for additional studies. Patients and MethodsUsing Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we identified 4404 patients diagnosed with muscle-invasive bladder cancer from 2004 to 2011. We further identified those who underwent a bone scan prior to treatment within 6 months of diagnosis and prior to any treatment with cystectomy, radiotherapy, or chemotherapy. We determined the proportion of patients who underwent a subsequent study (bone X-ray, bone CT, bone MRI, and/or bone biopsy) within 3 months of the bone scan and prior to treatment. ResultsAmong patients diagnosed with muscle-invasive bladder cancer, 1373 (31%) had a staging bone scan of whom 26% received a downstream study (n = 213). Overall, 61 patients (7%) received downstream bone-specific X-rays, more than 141 patients (>17%) received bone-specific CTs, and 28 patients (3%) received bone-specific MRIs. The use of bone biopsy was rare (n < 11; <1%). The total cost of all downstream studies was $103,468. Furthermore, there was a one-month delay in treatment for those who received a downstream study compared to those who did not (P < 0.001). ConclusionUse of bone scan in the staging of muscle-invasive bladder cancer often results in the need for additional downstream studies. The delay in treatment and cost burden of downstream studies highlights a potential disadvantage of the routine use of this staging modality.