Editing Prostate-specific antigen (section)

====Post-treatment monitoring====

PSA levels are monitored periodically (e.g., every 6–36 months) after treatment for prostate cancer – more frequently in patients with high-risk disease, less frequently in patients with lower-risk disease. If surgical therapy (i.e., radical prostatectomy) is successful at removing all prostate tissue (and prostate cancer), PSA becomes undetectable within a few weeks. A subsequent rise in PSA level above 0.2{{nbsp}}ng/mL<ref>{{cite journal | vauthors = Freedland SJ, Sutter ME, Dorey F, Aronson WJ | title = Defining the ideal cutpoint for determining PSA recurrence after radical prostatectomy. Prostate-specific antigen | journal = Urology | volume = 61 | issue = 2 | pages = 365–369 | date = February 2003 | pmid = 12597949 | doi = 10.1016/s0090-4295(02)02268-9 }}</ref> L{{Disputed inline|Post-treatment_monitoring:_no_references._Incorrect_units.3F|date=February 2014|reason=Should units be ng/mL?}} is generally regarded as evidence of recurrent prostate cancer after a radical prostatectomy; less commonly, it may simply indicate residual benign prostate tissue.{{Citation needed|date=February 2014}}

Following radiation therapy of any type for prostate cancer, some PSA levels might be detected, even when the treatment ultimately proves to be successful. This makes  interpreting the relationship between PSA levels and recurrence/persistence of prostate cancer after radiation therapy more difficult. PSA levels may continue to decrease for several years after radiation therapy. The lowest level is referred to as the PSA nadir. A subsequent increase in PSA levels by 2.0{{nbsp}}ng/mL{{Disputed inline|Post-treatment_monitoring:_no_references._Incorrect_units.3F|date=February 2014|reason=Should units be ng/mL?}} above the nadir is the currently accepted definition of prostate cancer recurrence after radiation therapy.{{Citation needed|date=February 2014}}

Recurrent prostate cancer detected by a rise in PSA levels after curative treatment is referred to as a "[[biochemical recurrence]]". The likelihood of developing recurrent prostate cancer after curative treatment is related to the pre-operative variables described in the preceding section (PSA level and grade/stage of cancer). Low-risk cancers are the least likely to recur, but they are also the least likely to have required treatment in the first place.{{Citation needed|date=February 2014}}