The two clinical trials, cited in your clip, can be found at these websites:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3387395/ (April 2012)
This trial included 44 participants who took 4000 IU of Vitamin D daily for 1 year.
Results:
"No significant changes in PSA levels were observed. However, 24 of 44 subjects (55%) showed a decrease in the number of positive cores or decrease in Gleason score; five subjects (11%) showed no change; 15 subjects (34%) showed an increase in the number of positive cores or Gleason score."

https://academic.oup.com/jcem/article/98/4/1498/2536841? (May 2013)
This trial involved 66 PCa patients scheduled to undergo radical prostatectomy. They were randomly placed into three groups and given vitamin D orally, once per day, for 3 to 8 weeks, up to the day before their RP surgery.
1) 400 IU (10 μg)
2) 10 000 IU (250 μg)
3) 40 000 IU (1000 μg).
Results:
- Groups 2) & 3) had lower blood serum levels of parathyroid hormone (PTH is a measure of PCa bone metastases) and PSA (see baseline/final chart attached).
- "In conclusion, our clinical trial data support the hypothesis that prostatic in vivo vitamin D metabolism can be modulated by high oral vitamin D dosing. Furthermore, the decrease in Ki67 labeling and modest declines in serum PSA and PTH with higher prostate calcitriol achieved with vitamin D doses (10 000 and 40 000 IU/d) suggest a potential clinical benefit. Lastly, the vitamin D doses (400–40 000 IU/d) were well tolerated by PCa patients without signs of toxicity."

Years ago I was found to have a Vitamin D deficiency. I currently take a 5000 IU Vitamin D softgel capsule daily, maybe I should increase that to 10,000 IU/day???