The following article features coverage from the American Urological Association (AUA) 2019 meeting. Click here to read more of Renal & Urology News’ conference coverage.

CHICAGO—Men with nonmetastatic castration-resistant prostate cancer (nmCRPC) who have a relatively short PSA doubling time (PSADT) are at increased risk of developing metastatic disease, new study findings presented at the 2019 American Urological Association annual meeting confirm. In addition, metastasis risk increased as PSADT decreased.

The study included 3579 patients with nmCRPC with a mean age of about 73 years identified using the Veterans Health Administration database. Investigators led by Stephen J. Freedland, MD, of the Samuel Oschin Comprehensive Cancer Institute at Cedars-Sinai Medical Center in Los Angeles, placed patients into PSADT groups based on 2-month intervals: ≤2, >2 to ≤4, >4 to ≤6, >6 to ≤8, >8 to ≤10, >10 to ≤12, and >12 months (reference group).

The risk of metastasis increased as PSADT decreased. Compared with the reference group, patients with a PSADT of >10 to ≤12, >8 to ≤10, >6 to ≤8, >4 to ≤6, >2 to ≤4, and ≤2 months had a 1.8-, 3.1-, 4.1-, 6.6-, 14.3-, and 33.8-fold increased risk of metastasis, respectively, in adjusted analyses, Dr Freedland and his collaborators reported.

In addition, the study demonstrated that patients with a shorter PSADT had higher all-cause and PCa-related health care resource use and costs. Compared with the reference group, patients in the ≤2, >2 to ≤4, >4 to ≤6, >6 to ≤8 month PSADT groups had significantly more PCa-related inpatient visits, longer hospital lengths of stay, greater numbers of outpatient and pharmacy visits, and higher all-cause and PCa-related costs.

The number of PCa-related outpatient visits decreased from 1.11 visits per patient per month (PPPM) in the ≤2 month group to 0.89, 0.73, 0.57, 0.56, 0.46, 0.44 visits PPPM in the >2 to ≤4, >4 to ≤6, >6 to ≤8, >8 to ≤10, >10 to ≤12, and >12 month PSADT groups, respectively. The number of pharmacy visits in these groups decreased from 0.45 PPPM to 0.41, 0.38, 0.28, 0.28, 0.26, and 0.20 PPPM, respectively.

Average all-cause and PCa-related total costs increased with decreasing PSADT, with average all-cause total costs increasing from $1778 PPPM for the reference group to $6161 for those in the ≤2 month group and average PCa-related total costs increasing from $699 to $4248 PPPM.

“This is the largest study to date that very strongly confirms the value of PSADT in predicting metastatic disease in men with nmCRPC,” Dr Freedland told Renal & Urology News. “Moreover, costs and health care resource use for these men goes up dramatically, too. Importantly, most men had longer doubling times (≥ 12 months) and thus are low-risk. However, for men with shorter PSADTs, given new options that can delay metastases in these men, consideration should be given to starting these men on therapy to delay metastases and reduce health care resource utilization.”

Pfizer Inc., and Astellas Pharma Inc. sponsored the study.

Read more of Renal & Urology News’ coverage of the AUA 2019 meeting by visiting the conference page.

Reference

Freedland SJ, Ramaswamy K, Lechpammer S, et al. Impact of prostate specific antigen doubling time on metastasis and increased costs associated with progression to metastatic castrate-resistant prostate cancer. Presented at the 2019 American Urological Association annual meeting held May 3-6 in Chicago. Abstract MP34-09.