Colonoscopy effects on serum prostate specific antigen levels

Effect of constipation on serum total prostate-specific antigen levels in men

OBJECTIVES

Many factors affecting serum prostate-specific antigen (PSA) levels have been described. The aim of this study was to examine the effect of constipation on serum PSA levels in men.

METHODS

Serum total PSA values were measured in 136 constipated patients before and after treatment for constipation. Moreover, they were compared with 45 control patients.

RESULTS

Serum total PSA values in the constipated patients before treatment were significantly higher than those in the control group (2.29 ± 1.29 ng/mL vs 1.28 ± 0.86 ng/mL, P < 0.0001). After the treatment of constipation, serum total PSA values in the constipated patients were still higher than those in the control group, but this difference was not statistically significant (P = 0.0871). After the treatment of constipation, prostate biopsy rates were 6.6% and 2.2% in the study and control group, respectively (P = 0.2769). No prostate cancer was found in both groups.

CONCLUSIONS

Constipation increases serum PSA levels in men. The presence of constipation must be considered in patients whose PSA is examined, especially in those with PSA levels that are borderline high or in the range of 2-10 ng/mL. Constipated patients must be first treated and then re-evaluated.

Serum levels of prostate specific antigen are elevated after colonoscopy

The risks of prostate cancer and colorectal carcinoma increase with age. So, colonoscopy and measurement of serum prostate specific antigen (PSA) may be performed during a short term in a given patient. We aimed to evaluate whether colonoscopy affects serum PSA levels and to evaluate the relationship between prostate volume and elevation in serum PSA levels after colonoscopy. This study included 44 consecutive male patients, who underwent colonoscopy. The mean age of the patients was 56.05±9.27 years. The mean time required for colonoscopy was 30 min. Serum PSA levels were measured 48-72 hours before colonoscopy, immediately after performing laxative enema, and at 24-48th hour, the 7th day, and the 14th day after colonoscopy in each patient. The serum PSA level was elevated after enema and at 24-48th hour and 7th day after colonoscopy from the baseline (p<0.05), and declined to the baseline by 14th day. When the cut off value of 20 cm3 for normal prostate volume was taken into account, the serum PSA levels were significantly higher at the 24-48th hour and the 7th day in patients with larger prostate volume (>20 cm3) than those with normal prostate volume (p=0.013 and p=0.009). These results suggest that PSA is easily released by manipulations from the larger prostate. In conclusion, serum PSA levels were elevated during 7 days after colonoscopy. Before performing invasive procedures, patients with high serum PSA levels should be asked whether colonoscopy was performed prior to the measurement.

Do patients undergo prostate examination while having a colonoscopy?

OBJECTIVES

To determine the rate at which physicians report performing a digital rectal examination and comment on the prostate gland before performing colonoscopy in men 50 to 70 years of age.

METHODS

A retrospective chart review of all men 50 to 70 years of age who had a colonoscopy in Kingston, Ontario, in 2005 was completed. It was noted whether each physician described performing a digital rectal examination before the colonoscopy, and if so, whether he or she commented on the prostate.

RESULTS

In 2005, 846 eligible colonoscopies were performed by 17 physicians in Kingston, Ontario. In 29.2% of cases, the physician made no comment about having performed a digital rectal examination; in 55.8% of cases, the physician commented on having completed a digital rectal examination but said nothing about the prostate; and in 15.0% of cases, the physician made a comment regarding the prostate. No physician consistently commented on the prostate for all patients, and in no circumstances was direct referral to another physician or follow-up suggested.

DISCUSSION

A colonoscopy presents an ideal opportunity for physicians to use a digital rectal examination to assess for prostate cancer. Physicians performing colonoscopies in men 50 to 70 years of age should pay special attention to the prostate while performing a digital rectal examination before colonoscopy. This novel concept may help maximize resources for cancer screening and could potentially increase the detection rate of clinically palpable prostate cancer.