SIU 2018: Oncology Updates -PRIAS-JAPAN Study

Seoul, South-Korea (UroToday.com) Dr. Sugimoto provided an update on the results of the PRIAS-Japan study, which is the subset of patients enrolled in Japanese center for the international PRIAS study.

The PRIAS (Prostate Cancer Research International: Active Surveillance) study has been ongoing observational study since December 2006 focusing on early prostate cancer (cT1c-T2N0M0). It has now accrued over 7500 patients in 22 countries!

  • Inclusion criteria (is relatively strict compared to other AS studies):
  • PSA <= 10 ng/mL
  • PSAD < 0.2
  • cT-stage T1c or T2
  • Gleason score 3+3=6 only
  • Only 1-2 biopsy cores involving cancer
  • Patients are following, and have repeat biopsies at 1, 4, 7 and 10 years (and then every 5 years after)
In 2016, Bokhurst et al. published the initial PRIAS data (5302 patients). In this study, only 57 deaths were identified, and only 1 was from prostate cancer. 

He highlighted other large AS results as well, including:
1. Johns Hopkins (Tosoian et al JCO 2015) – 10 and 15-year CSS was 99%. 10 and 15-year OS was 93 and 69%, respectively.
2. ProtecT study (Hamdy et al. NEJM 2016) – 20% of the active monitoring arm had Gleason 7-10 prostate cancer. Despite this, over a 10-year period, there was very little prostate cancer death! Patients do well on active monitoring.
3. Sunnybrook (Klotz et al. JU 2016) – patients with Gleason 6 disease did very well. However, patients with Gleason 7 disease (especially Gleason 4+3=7 or PSA >20) did poorly with unacceptable metastases rates. 

The PRIAS-Japan study includes 39 institutions in Japan since initiation in 2010. It has accrued 841 men so far, ~100/year. Median PSA at enrollment 5.28, 90% cT1, 97% Gleason 6 (1% Gleason 5 and 1% Gleason 7), 75% were just 1 core positive.

First, he looked at the re-biopsy data at 1 year and 4-years. Both flowsheets are listed below:

1 year:
re biopsy data at 1 year
  • Of 658 men who continued on AS at 1 year, 82.5% agreed to repeat biopsy
  • Of these, 26.8% were reclassified. Some based on volume alone, some due to grade progression, and most due to both!
4-years:
re biopsy data at 4 years
  • Of 185 men who continued on AS at 4 year, only 60.5% agreed to repeat biopsy at 4 years
  • Of these, 22.3% were reclassified. Some based on volume alone, some due to grade progression, and some due to both
  • Interestingly, reclassification rate was similar to the one at 1 year
Predictors for reclassification (Sugimoto et al. World J. Urol 2015)
1. Positive core rate was the strongest predictor of reclassification
2. PSA doubling time was not associated with reclassification and cannot predict pathologic findings accurately

In the PRIAS-Japan study, the retention rate on AS is 69% at 2-years and 49% at 5-years. For those men who do move onto secondary treatment after AS, radical prostatectomy is the most common treatment (~36%), followed by LDR (20%), EBRT (19%), ADT (12%). 9% go on to watchful waiting!

Lastly, they also assessed quality of life results while on AS. This data was a little less concrete. Basic take-home – the QOL of men on AS was better than the general population at enrollment, and was maintained over follow-up (especially mental component). There was a deterioration in the physical component at around year 3. But, more work is required!

Presented by: Mikio Sugimoto, Japan 

References: 
1. Tosoian et al JCO 2015
2. Hamdy et al. NEJM 2016
3. Klotz et al. JU 2016 
4. Sugimoto et al. World J. Urol 2015 

Written By: Thenappan Chandrasekar, MD, Clinical Instructor, Thomas Jefferson University Twitter: @tchandra_uromd, @TjuUrology at the 38th Congress of the Society of International Urology - October 4- 7, 2018 - Seoul, South Korea
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