Prostate-specific antigen (PSA) is currently an important marker for early diagnosis and monitoring of prostate cancer outcomes, but PSA is not specific to prostate cancer. The three main diseases of the prostate (BPH, prostatitis, and prostate cancer) can all raise serum PSA values. There are many other factors that can affect serum PSA values. To investigate the effect of acute prostatitis on serum total prostate-specific antigen (T-PSA), free prostate-specific antigen (F-PSA) and free/total prostate-specific antigen (F/T) ratio.
We conducted dynamic observation on the changes of serum T-PSA, F-PSA and F/T ratio in 35 patients with acute prostatitis before and after treatment from January 2001 to March 2004, and report them as follows.
1.Data and methods
1.1 Clinical data
There were 35 cases in this group, aged 23-82 years old, with an average of 56.5 years old. Some patients had perineal and lumbosacral pain, swelling and discomfort or rectal irritation symptoms. The history of the disease ranged from 1 to 7 days, with an average of 3 days, and the body temperature ranged from 38.7 to
40.0℃, average 39.4℃. There were 20 cases of dyspareunia, 3 cases of acute urinary retention, and 2 cases of localized fluctuating sensation in the prostate on rectal finger examination. Laboratory examination: blood leukocytes (8.3~23.1)×109/L, including >10×109/L in 33 cases, neutrophils accounted for 82.6%~93.7%; urine routine leukocytes +~+++/HP; urine culture positive results in 21 cases, including 15 cases of E. coli, 4 cases of Pseudomonas, 2 cases of Enterococcus.
The average volume of prostate was 36.3±15.2 ml (18.5~67.4 ml) in 30 patients. 24 hypoechoic areas were found in 18 cases, 13 cases had abundant blood flow in the prostate, and 2 cases had liquid dark areas (unilateral). 18 patients had urine flow rate examination, and Qmax was <15 ml/s in 12 cases.
The patients were treated with intravenous fluoroquinolones or third-generation cephalosporins for 1 week, and then changed to oral medication for 3-4 weeks. If there is difficulty in urination, alpha-blockers are added. Two cases with prostate abscess formation were treated with ultrasound-guided puncture and drainage. After treatment, the patient’s body temperature returned to normal in 3 to 5 days. After 2 weeks of treatment, the blood and urine routine and urine culture were normal, and the urinary flow rate improved in those with difficulty in urination.
1.2 Detection method
The changes of serum T-PSA, F-PSA and F/T ratio before and after 1 week, 1 month and 3 months of treatment were measured by immunoluminescence method.
1.3 Statistical analysis
The data obtained were expressed as -x±s, and the analysis of variance between groups was performed using SPSS 10.0 statistical software, and the significance test level was α=0.05.
2. Results
The changes of serum T-PSA, F-PSA and F/T ratio in patients with acute prostatitis before and after treatment at different times are shown in Table 1.
Table 1 Changes in serum T-PSA, F-PSA, F/T ratio before and after treatment of acute prostatitis
Item Before treatment 1 week after treatment 1 month after treatment 3 months after treatment
T-PSA/μg・L-1 46.21±28.42 28.12±16.35 18.48±8.64 3.64±1.48
F-PSA/μg・L-1 5.32±3.43 3.14±1.98 1.82±0.96 0.54±0.22
F/T 0.11±0.04 0.11±0.03 0.10±0.04 0.16±0.06
T-PSA, by ANOVA, F=4.528, P<0.05, indicating that the serum T-PSA values at each time point were different; then two-by-two
F-PSA, by ANOVA, F=4.720, P<0.05,
F/T, by ANOVA, F=3.201, P<0.05, indicating a difference in the F/T ratio at each time point; then two comparisons were made,
The difference between the F/T ratios of patients with acute prostatitis at 3 months after treatment was statistically significant (P<0.05) compared with those before treatment and at 1 week and 1 month after treatment, while the difference between the F/T ratios before treatment and at 1 week and 1 month after treatment was not statistically significant (P>0.05). At 3 months after treatment, 5 patients (16.7%) still had serum T-PSA values greater than 4.0 μg/L (4.12-6.08 μg/L), and the F/T ratio was less than 0.15. After prostate puncture biopsy, one case of prostate cancer (Gleason score 2+2) was found, and the rest of the pathology showed prostate hyperplasia with different degrees of acute and chronic inflammatory manifestations.
3. Discussion
The main molecular forms of serum PSA commonly used in clinical practice are T-PSA and F-PSA. T-PSA is the molecular form of all PSA that can be detected in serum, with PSA-α1-anti-chymotrypsin (70%-85%) and F-PSA being the main ones; F-PSA is a kind of PSA that exists in the free non-complexed form in serum and is inactive in serum. T-PSA, F-PSA and F/T ratio are of great value in the diagnosis and differential diagnosis of prostate cancer. The factors that determine the serum PSA value are mainly the following:
①The amount of PSA produced by prostate epithelial cells;
(2) The ease of PSA entry into the blood;
(3) the clearance rate of PSA in the circulation.
Under normal circumstances, the PSA-rich prostate alveolar contents and the lymphatic system between the basement membrane, basal cells and the endothelial layer of the barrier, so that PSA can hardly enter the circulation through the lymphatic system, so the PSA content in peripheral blood is very low. The PSA concentration in prostatic fluid, seminal plasma and serum PSA concentration can maintain a 1 million fold difference. The normal serum PSA reference value is <4μg/L. The pathological changes in acute prostatitis are mainly manifested by a large infiltration of inflammatory cells (neutrophils, monocytes, macrophages) in the prostate gland epithelium, stroma and lumen of the glandular ducts.
These inflammatory reactions destroy the integrity of the prostate ducts and the original physiological barrier, causing PSA to leak into the circulation from the prostate ducts and alveoli, and inflammation also increases the permeability of the lymphatic vessels and capillaries, making it easy for PSA to enter the circulation, thus causing an increase in serum PSA. The actual fact is that there are more prostate follicles or epithelium in the prostate than in chronic prostatitis, and the degree of damage is also greater.
Therefore, acute prostatitis leads to a greater increase in serum PSA levels than chronic prostatitis. pansadoro et al. analyzed serum PSA in 72 patients with prostatitis. 17.3% of patients had PSA >4.0 μg/L (4.3 to 39.0 μg/L), with 71% of patients with acute prostatitis having serum PSA >4.0 μg/L, while only In a study by Kravchick et al, acute prostate caused a significant increase in serum PSA, and at 3 months after treatment, 39% of patients still had PSA values >4μg/L.
The present study showed that acute prostatitis significantly increased serum T-PSA and F-PSA values, while the F/T ratio significantly decreased, indicating that T-PSA was more elevated than F-PSA in acute prostatitis. At 1 week and 1 month after treatment, the T-PSA and F-PSA values decreased significantly over time (P<0.05), but remained at a high level, and the F/T ratio was not statistically significant compared with that before treatment (P>0.05).
By 3 months after treatment, the T-PSA value had decreased to a normal level (3.64±1.48 μg/L), while the F/T ratio was higher than before treatment and at 1 week and 1 month after treatment (P<0.05). Because the half-life of T-PSA is 2.2~3.2 d, while the half-life of F-PSA is less than 2 h. The clearance rate of F-PSA is faster than that of T-PSA, and the F/T ratio increased at this time, indicating that F-PSA enters the blood circulation more easily than T-PSA as the inflammation of the prostate gland subsides and the damage is repaired.
The serum PSA level will gradually return to normal after the inflammation has subsided with treatment. The duration of antibiotic treatment for acute prostatitis is uncertain, but most scholars believe that the duration of treatment should be long rather than short, if the patient reflects well on the treatment and the causative organism is sensitive to the drug, continuous medication for 3 to 4 weeks can prevent recurrence.
The present study also showed that after 2 weeks of effective treatment, the patient’s symptoms, signs, blood and urine routine, and urine culture were normalized, but the patient’s serum T-PSA and F-PSA values were still high at 1 month after treatment, indicating that the inflammation had not subsided and the inflammatory damage had not been completely repaired, which also supports the principle that the course of treatment should be long rather than short, and the serum PSA value can be used as a reference for the clinical treatment of acute prostatitis. The serum PSA value can be used as a reference indicator for clinical treatment of acute prostatitis.
The F/T ratio of the serum PSA is significantly higher in acute prostatitis, and the F/T ratio decreases, whereas in most patients with prostate cancer the serum PSA is also higher and the F/T ratio is smaller than that of BPH, so it is easy to misdiagnose acute prostatitis as prostate cancer. The F/T ratio of our patients was found to be the same as that of BPH. The F/T ratio in our patients was also low (0.10-0.16). In clinical practice, it should be differentiated based on typical medical history, rectal examination, dynamic observation of PSA and prostate biopsy.
In a study by Kravchick et al. 28 patients with acute prostatitis, the PSA value was still high in 11 cases at 3 months after treatment, and prostate biopsy revealed 3 cases of prostate cancer, while in 5 cases at 3 months after treatment. In our group, five patients with serum T-PSA value >4μg/L and F/T ratio <0.15 underwent prostate puncture biopsy and one case of prostate cancer was found.
The results of this study showed that acute prostatitis causes a significant increase in serum T-PSA and F-PSA values, and a significant decrease in F/T ratio, and the effects last for 3 months. The effect of acute prostatitis on PSA should be taken into account when it is used in clinical practice.