Colonoscopy effects on serum prostate specific antigen levels.

INTRODUCTION: To evaluate the colonoscopy effects on serum levels of prostate specific antigen (PSA) and PSA ratio. SUBJECTS AND METHODS: Thirty men were studied (median age 68 years, range 32-89). All of them had their serum PSA (total and free) measured 24 hours prior to colonoscopy and also 24 hours, 7 and 30 days after procedure. RESULTS: 14 of 30 (47%) patients, had significantly (p = 0.045) increased Total PSA levels 24 hours after the procedure, 14 (47%) patients had insignificantly (p = 0.139) increased levels 7 days after, while 13 (43%) of them had insignificantly (p = 0.061) increased levels 30 days after colonoscopy. In 7 patients (23%), with total PSA levels in the "gray zone" (4-10 ng/ml) before colonoscopy, a near significant (p = 0.063) raise in PSA ratio was also observed 24 hours after. CONCLUSION: Flexible colonoscopy affect serum PSA (free and total) levels in certain patients. Special attention must be given to those patients with PSA levels in the "gray zone" before colonoscopy.