Urinary PSA level and relative tumor volume after prostate biopsy

Mechanisms of Prostate Cancer Cells Survival and Their Therapeutic Targeting

Prostate cancer (PCa) is today the second most common cancer in the world, with almost 400,000 deaths annually. Multiple factors are involved in the etiology of PCa, such as older age, genetic mutations, ethnicity, diet, or inflammation. Modern treatment of PCa involves radical surgical treatment or radiation therapy in the stages when the tumor is limited to the prostate. When metastases develop, the standard procedure is androgen deprivation therapy, which aims to reduce the level of circulating testosterone, which is achieved by surgical or medical castration. However, when the level of testosterone decreases to the castration level, the tumor cells adapt to the new conditions through different mechanisms, which enable their unhindered growth and survival, despite the therapy. New knowledge about the biology of the so-called of castration-resistant PCa and the way it adapts to therapy will enable the development of new drugs, whose goal is to prolong the survival of patients with this stage of the disease, which will be discussed in this review.

Do the values of prostate specific antigen obtained from fresh and dried urine reflect the serum measurements?

Aim:

To investigate if free PSA (fPSA) and total PSA (tPSA) values obtained from simultaneously collected urine, fresh and dried on filter paper, reflect the serum free and total PSA.

Materials and Methods:

The sera and 20 cc first voided urine from 33 consecutive men aged between 40 and 84 (mean 61 ± 12), were collected in the morning and delivered to the laboratory. Three different aliquots of 100 microgram urine were taken with automatic pipette and dropped on 3 certain areas of a filter paper and allowed to dry for each patient. On each paper, borders of dried urine were marked. PSA values were obtained from the sera and fresh urine samples and recorded. Later on particular days dried urine samples were dissolved and eventually PSA values were derived and recorded again. The results were compared to each other. Correlations were evaluated by using an SPSS statistics program.

Results:

Serum PSA values correlated weakly (r < 0.24) with fresh and dried urine PSA values. While PSA in fresh and dried urine samples showed strong correlation (0.5 < r < 0.74), a very strong correlation (r > 0.75) among PSA values of dried urine samples of 1-day, 7- and 28-days, were seen.

Conclusions:

We conclude that PSA values obtained from fresh and dried urine could not reflect serum PSA values. But, because dried urine on a filter paper can be stable for years, it could be used for forensic purposes.

The analysis of some factors that influence on serum PSA level in localized prostate cancer patients: mathematical model

INTRODUCTION

Serum prostate specific antigen (PSA) concentration in localized prostate cancer (PCa) patients depends of numerous factors related to tumor, prostate and the patient. Tumor factors include tumor volume, localization, growth rate and aggressiveness. Prostate factors include prostate volume, the activity of dihydrotestosterone (DHT) and PSA synthesis. Host factors include androgenic status and total blood volume.

OBJECTIVE

to discuss all the possible factors that influence on serum PSA levels in localized PCa patients. To present the mathematical model that predicts serum PSA concentration in localized PCa patients.

METHODS

Mathematical model is based on the hypothesis that tumor-related PSA molecules are released from the epithelial prostatic cells around the tumor, so called "Destruction Zone" around the tumor (DZ). The amount of PSA is dependent of DZ volume. Moreover, DZ volume depends on tumor volume, tumor localization in the prostate and tumor growth rate.

RESULTS

The study offers the wide spectrum of PSA values, dependent on tumor, prostate and patient characteristics. These values are comparable with the empirical results in the literature, especially if tumor-volume doubling time of three years is entered into the calculations.

CONCLUSION

Although with some limitations, this mathematical model can explain the great variety of PSA serum concentrations in PCa patients.