DIAGNOSTIC UTILITY OF PROSTATE SPECIFIC ANTIGEN FOR DETECTION OF PROSTATIC LESIONS

Background: Carcinoma of prostate is one of the common tumors of old age in men. With digital rectal examination (DRE), prostate specific antigen (PSA) is a major screening tool for prostate cancer. The cutoff value for PSA of 4.0 ng/mL gives the highest sensitivity and highest specificity. Several modifications of PSA testing have been developed and may be beneficial for select populations. Methods: The study includes 180 cases between 48 to 76 years of age group. Serum PSA level and Histopathology of prostatic biopsy was done and correlate. Results: Widespread use of PSA for early detection prostate cancer in india. In present study 56% cases of BPH with mean age 57.77 ±4.86. and 33.1% Malignant (Adeno ca. + TCC) with mean age 65.70 ±5.64.


Introduction
Prostate cancer is an important growing health problem, presenting a challenge to urologists, radiologists and pathologist 1,2 Currently, many men are identified as having early prostate cancer through the use of prostate specific antigen (PSA) screening 3,4,5,6 . Carcinoma of the prostate is the most common malignant tumor in men over the age of 65 years 7 , with an estimated 41,000 Americans dying from prostate cancer annually 8 . Currently it is the most common male malignancy in the United States of America and the majority of cases are diagnosed at a time when tumor has extended beyond the confines of the gland, making it incurable. In the European Union 13% of malignancies diagnosed in men comprise prostate cancer 9 . Diagnostics techniques used in prostate cancer have been evolved greatly with technological developments but the classical digital rectal examination is still the mainstay for the diagnosis of any prostatic disease. The accuracy rate of digital rectal examination in detecting malignancy is 20-40% in different series 10,11,12 . Prostatic Acid Phosphatase has been used extensively in the last 50 years as marker to diagnose prostate cancer. PSA was identified 1972. DRE and PSA have been recommended test in guidelines of the American cancer society since 1993 for annual check up of men aged 50 years or above 10,11 . The use of prostate specific antigen coupled with digital rectal examination has led to improved detection of prostate cancer and has resulted in earlier diagnosis and treatment 13,14 . Prostate-specific antigen (PSA) is the most useful tumor marker in the diagnostics of prostate carcinoma 15 . PSA is serin protease produced by ductal and acinal epithelial cells of normal, hyperplastic, and malignant tissue of the prostate. By the influence of pathological processes the cell integrity is destroyed leading to release of PSA into circulation, i.e. the processes inside prostate, such as hyperplasia, inflammation, tumors, lead to the increase of serum PSA value the most frequently 16,17,18 . The investigations have revealed that every gram of cancer prostate tissue increases the value of serum PSA for 2.3 ng/ml in average, while every gram of hyperplasic tissue increases the same parameter 10 times less compared to cancer tissue 19,20 . While PSA is primarily produced by prostatic epithelial cells, PSA has also been noted to be detected in trace amounts in the periurethral glands, endometrium, normal breast tissue, breast tumor, breast milk, adrenal neoplasm, and renal cell carcinoma 21,22 . Because PSA usually found in low concentration in serum, measured elevation of PSA in serum have allowed it to become an important marker for prostate cancer 23 . The measurement of the PSA level has been used as a screening tool for prostate cancer since the mid-1980s. Currently, first-line screening for prostate cancer consists of annual DRE and IJBAR (2012) 03(04) www.ssjournals.com determination of serum PSA levels. The upper limit of normal for PSA values is generally considered to be 4.0 ng/mL; between 4 and 10 ng/mL is considered borderline and more than 10 ng/mL is considered high. Patients with a PSA value greater than 4 ng/mL, regardless of DRE results, generally undergo biopsy. The cutoff value of 4.0 ng/mL represents the level at which the highest sensitivity (detection of the largest number of prostate cancers) and highest specificity (exclusion of the greatest number of men without prostate cancer) are present. As there is no value of PSA at which the definitive diagnosis of prostate cancer can be made, and a positive finding on DRE is also not 100% specific, biopsy of the prostate is still required for the diagnosis of prostate cancer 24  The biopsy was performed with "Tru-cut" needle using transrectal or transperineal approach with previous preparing of patient (purgation and antibiotic protection). Also, the material obtained by transurethral resection (TUR) of prostate, used in diagnostic and therapeutic purposes, was analyzed. Fixation of tissue samples has been done in 10% formaldehyde solution for 24 hours. The tissue was prepared routinely, put in paraffin, cut on microtome to the thickness of 4 microns, and then the sections were stained by H& E stain, and reported. Statistical Analysis: Data from the study was analysed separately using statistical Package for Social Sciences. Results are presented as Mean ± SD (Standard deviation).    <50  0  4  0  0  1  5  51-60  9  71  7  0  4  91  61-70  36  27  5  2  0  70  >70  13  1  14  Total  58  102  13  2  5  180   Table No.02 shows adenocarcinoma is more common between 61-70 years of age and BPH is more common in 51-60 years of age.

Discussion
Carcinoma of prostate is common cancer in India due to increasing life expectancy and relatively better diagnostic method. The gold standard triad for diagnosing prostate cancer comprised DRE, PSA level and transrectal ultrasonography 28 . The DRE has always been the primary method for evaluating the prostate. It is easy to conduct and cause little discomfort to the patient but Smith and Catalona showed that the DRE depends on the investigator and has great inter-examiner variablility 29 .DRE is neither specific nor sensitive enough to detect prostate cancer and is unlikely to be improved 30 .
To improve the detection rate of the prostate cancer, the DRE should be followed by a test with high sensitivity. PSA testing provides such a method, being very sensitive.The frequency of the diagnosis of prostate cancer has increased substantially since the introduction of PSA screening 31,32 .
In the Present study most common lesion is BPH with mean age 57.77 ±4.86. and BPH is more common between 51 to 60 years of age. Adenocarcinoma is second most common lesion in our study. And adenocarcinoma is most common type of malignancy in prostate.

Conclusion
Prostate specific antigen (PSA) is specific for the prostate. PSA is raise >10 ng/ml in adenocarcinoma and in TCC. In Benign prostatic lesion PSA level is in between 0 to 4.0 ng/ml. In present study shows that DRE and PSA are the most useful front line methods for assessing and individual's risk of prostate cancer. In addition elevated level more than 4.0 ng/ml and abnormal DRE with TURP biopsy is most useful and accurate diagnostic method for prostate.