This is Dr. DavidI am a cancer doctor. most PSA spikes up in a short period of time usually is a result of prostatitis or prostate infection or inflammation. any sort of sex or prostate activity or prostate infection can cause the PSA to spike up to 11 or higher for a short period of timeusually a course of antibiotics and repeating the PSA in 1-2 months will show that it comes back down to a more normal range. there is also controversy about using PSA as a screening tool to detect early prostate cancers in men over 70. many doctors feel that it might not be beneficial to find early cancers because treating them at your age most likely will not make a big difference at your age
let me know if yo have questions.