Effect of Colonoscopy on Prostate-Specific Antigen; New Words about an Old Subject

Background: The increasing in prostate specific antigen (PSA) level not only causes concern for the patiens, but also leads to unnecessary investigation of these patients. The age of these patients is generaly high and may require colonoscopy for various reasons. The results of a few recent studies on the effect of colonoscopy on PSA level were controversial. Objectives: Therefore, we decided to study the effect of colonoscopy on PSA level in Iran and compare these results with the results of previous study in other countries. This was the first study in Iran to report such finding. Methods: Forthy-two patients between 40 to 70 years included in a prospective study, before and after study in Imam Reza hospital in Tehran, Iran from 2016 to 2017. Colonoscopy was performed in all of patients and the PSA level was measured before and 72 hours after colonoscopy. The result was analyzed with paired t test and ANOVAs test and the level of significant was 0.05. Results: The mean of total PSA before colonoscopy was 1.87 ng/mL with standard deviation (SD) 1.04 ng/mL and total PSA after colonoscopy was 2.02 ng/mL with standard deviation 1.13 ng/mL that was statistically significant (P = 0.01). Conclusions: According to the finding of the present research, colonoscopy increases the PSA level. Another finding of the present study was that these changes are particularly significant in older than 50 years. In patients with high levels of PSA, before performing any other diagnostic procedure, it is necessary to question for a colonoscopy before measuring PSA. If this is done, the PSA should be repeated for 7 to 14 days after colonoscopy.