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INTRODUCTION: The reported cancer detection rate of Trans-Rectal Ultrasonography (TRUS) biopsies (TRUS biopsy yield) has been around 30 percent in western countries. However it is much lower in Asian countries, including India. Hence a larger proportion of patients in India undergo unnecessary biopsies. AIMS: To find out the cancer detection rate of TRUS biopsy (TRUS biopsy yield) in contemporary Indian population. Also, to study the positive predictive values at different serum Prostate-Specific Antigen (PSA)/PSA Density (PSAD) cut off levels and suspicious Digital Rectal Examination (DRE) findings. MATERIALS AND METHODS: This retrospective study was carried out in a tertiary care institute. All symptomatic patients who underwent TRUS guided biopsy for indication of raised serum PSA level (>4 ng/ml) or suspicious DRE findings (nodule, irregularity, hard consistency, immobile rectal mucosa) from January 2012 to December 2014 were included. For serum PSA range (4-10) ng/ml, TRUS guided biopsy was done in patients with percent free/total PSA < 25. Statistical analysis used were Chi-square test, Mann-Whitney U-test, Spearman's rank correlation analysis and Receiver-Operating Characteristic (ROC) curve. RESULTS: Out of the 235 patients included, 60 patients had malignancy (overall cancer detection rate= 25.53%). The cancer detection rate for PSA ranges of (4-10) and (10-20) ng/ml was as low as 5.95% and 13.16% respectively. Patients with malignant disease had significantly smaller prostate gland size than patients with benign disease (53.89 vs 63.06; p-value <0.05). On the other hand, cancer detection rate was 100% for PSA greater than 50ng/ml. The cancer detection rates were only upto 10% for PSA density ranges upto 0.25 ng/ml/cm3. The Area Under the Curve (AUC) for PSA and PSAD was 0.876 and 0.884 respectively. Only one patient (0.43%) had post-biopsy complication (acute bacterial prostatitis) requiring hospital admission. CONCLUSION: The current serum PSA and PSAD cut offs of 4 ng/ml and 0.15 ng/ml/cm3 need to be raised for Indian population to increase its positive predictive value. Prospective study validation of this finding is lacking.
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CONTEXT: Gates method tends to over-estimate glomerular filtration rate (GFR) in borderline functioning kidneys. We study the role of calculated GFR in these cases in decision-making regarding performing kidney-sparing surgery or nephrectomy. AIMS: The aim of this study is to find the correlation between GFR calculated by percutaneous nephrostomy (PCN) urine creatinine clearance in obstructed kidneys and GFR by radionuclide scintigraphy. It also studies the role of this calculated GFR in borderline functioning kidneys. SETTINGS AND DESIGN: Single tertiary care center; retrospective. MATERIALS AND METHODS: A total of 46 patients in whom PCN was inserted as an emergency measure in an obstructed kidney and for whom diethylene-triamine-penta-acetic acid/ethylene-di-cysteine (DTPA/EC) scan was also done (Gates method) were analyzed retrospectively. PCN creatinine clearance was calculated for 3 consecutive days, and the mean value was used. STATISTICAL ANALYSIS USED: Pearson's correlational analysis; Chi-square test. RESULTS: Overall strong correlation was found between the two GFR values (Pearson's r = 0.540692, P < 0.001). Totally 26 patients (56.52%) had comparable GFR values (P > 0.05). Among the 36 patients with borderline functioning kidneys, DTPA/EC scan significantly over-estimated GFR in one-third of the patients. The management plan was changed in 7 out of those patients (46.67%), with nephrectomy performed in all instead of kidney-sparing procedure. When the highest value of calculated GFR was compared, 28 patients had comparable GFRs (60.87%). CONCLUSIONS: GFR based on radionuclide scintigraphy may be insufficient for evaluation of residual renal function to determine the management of obstructed kidney with borderline function. For adequate decision-making, other factors including creatinine clearance via PCN should also be considered. Gates method tends to overestimate GFR as compared to calculated creatinine clearance at low GFR levels.
