Can Sexual Activity before a PSA Test Elevate PSA Level?

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Johns-Hopkins which publishes a bunch of newsletters and white papers on PCa uses this "fact" as a prominent part of their promotions.  That leads me to think it is not so controversial.  

Prostate massage play is a prominent feature of sexual play in the gay community, and urologists in San Francisco who have many gay men in their practices are advising abstinence for longer periods more like a week.  And in the community of gay men who are into very aggressive and active anal play the "folklore" says that their PSAs go way up and take several weeks to a month to return to "normal".  

It would be enlightening to know if any "controlled" studies, or even interview/survey studies have sought to establish facts about how much sexual activity affects PSA and whether the intensity of the play is a factor as well.