Overuse of imaging in prostate cancer staging

To examine prostate cancer staging in real-world clinical practice.

We retrospectively analyzed 698 patients referred to the Department of Urology at Kagawa University Hospital from 25 facilities for prostate cancer treatment from June 2014 to December 2023. Patients treated with dutasteride (n = 10) and who underwent staging at our institution (n = 197) were excluded. The outcomes of interest were the proportion of computed tomography and bone scintigraphy, diagnostic rates of metastasis stratified by D'Amico risk, and incidental findings on computed tomography. We estimated the number of low-risk patients based on the Japan Study Group of Prostate Cancer study and 2019 cancer statistical data. We calculated the staging costs of omitting computed tomography and bone scintigraphy in low-risk patients.

The proportion of D'Amico low-, intermediate-, and high-risk patients was 15.7% (n = 77), 45.2% (n = 222), and 39.1% (n = 192), respectively. The percentages of computed tomography and bone scintigraphy performed according to risk were 88.3% and 67.5% for low risk, 98.6% and 80.2% for intermediate risk, and 98.4% and 94.3% for high risk, respectively. The diagnostic percentages for lymph node, organ, and bone metastases by risk were 0%/0%/0%, 0%/0%/0.5%, and 8.9%/0.5%/9.3% for low-, intermediate-, and high-risk, respectively. Incidental findings were present in 2.7% of cases. By omitting computed tomography and bone scintigraphy for low-risk patients, the total staging cost could be reduced by USD 4.07 million (607 million Japanese yen) annually.

We highlight the potential overuse of imaging in prostate cancer staging. Recognizing the excessive use of diagnostic imaging can reduce medical costs.