What Causes Slightly Elevated PSA Levels After Having Levothyroxine?

Is there any link between Levothyroxin and PSA? I ve had a radical prostectomy, followered by 6 weeks of radiation. PSA readings have been very minimal during the past three years, edging up at glacial speed to 1.0. Suddenly in the past 6 months is almost doubled to 1.9. Still small, I know, but... Six months ago I also switched from Levothyroxin (Synthroid) to dessicated thyroid extract. Is there a known correlation somewhere?