Prostate Cancer Cohort Shows Where Active Surveillance Presents Lowest Risk

Active surveillance for lower-risk prostate cancer patients produced a high rate of metastasis-free survival, with only a handful of men developing metastases, typically after more than 5 years.

Still, researchers from the University of California San Francisco who tracked the men were able to identify some risk factors among the group.

Data published this month in the Journal of Urology offered a look back at 1450 men enrolled in active surveillance between 1990 and 2018 at UCSF, who had low- or intermediate-risk disease, as defined by stage cT1-2, a prostate specific antigen (PSA) of less than 20 ng/ml, and a biopsy Grade Group (GG) of 1-2.

The patients were divided in 3 risk groups based on diagnostic group (GG) and PSA density (PSAD). The study’s primary outcome was metastatic prostate cancer detected on imaging, or a prostatectomy. The researchers also tracked whether the cancer stage was later upgraded, if the patient later received active treatment, as well as survival outcomes.

After a median follow-up of 77 months, the 7-year prostate-specific metastasis-free survival rate was 99%; among the group, 15 men developed metastases at a median of 62 months, with 69% of these limited to lymph nodes.

The researchers noted that men with GG2 disease had a lower metastasis-free survival rate compared with those who had GG1 disease at diagnosis. Patients who had 4 and 5 index lesions at diagnosis based on the Prostate Imaging Reporting and Data System (PI-RADS), as detected by magnetic resonance imagining (MRI) also had a higher risk of metastases.

Among the group, 1,303 patients (90%) were initially diagnosed with GG1 and 147 (10%) with

GG2, while 24% had PI-RADS 4-5 index lesions. The mean time to active treatment was 32 months, and 59% had 7 years of treatment-free survival. The 562 men who eventually received treatment did so through a variety of methods, including 412 (73%) who had a radical prostatectomy, 135 who had radiation, 11 who had hormonal or advanced therapy, and 4 who had focal therapy. One patient was lost to follow-up.

A total of 64 men died over a mean follow-up time of 84 months; 4 died due to prostate cancer. At 7 years, the overall survival was 97% for the entire cohort; the GG1 group had PSAD of less than 0.15 ng/ml/cm3 having the best survival (98%), those with PSAD of at least 0.15 ng/ml/cm3 having the next-best rate (96%) and those with GG2 having a survival rate of 87%.

“Active surveillance seems to preserve favorable long-term prognosis, as metastases and prostate cancer specific death are rare,” the authors concluded. However, the authors cautioned that there are specific risk factors, even when overall risk is comparatively low, that should be considered when doctors and patients discuss active surveillance.

Reference

Maggi M, Cowan JE, Fasulo V, et al. The long-term risks of metastases in men on active surveillance for early stage prostate cancer. J Urology. 2020;204:1222-1228. https://doi.org/10.1097/JU.0000000000001313