PARENT SESSION
1:30 PM to 3:30 PM
Wednesday, April 25, 2001
Poster Session 28 Tumor Physiology and Microenvironments
Room: Exhibition Center

(P28-383) Increased PSA mRNA expression during brachytherapy procedure in peripheral blood of patients with prostate cancer.

Siddiqua, Ayisha¹, Chendil, Damodaran¹, Das, Anindita¹, Rowland, Randall², Ahmed, Mansoor¹, Mohiuddin, Mohammed¹, ^{1 2}

ABSTRACT-
Brachytherapy requires the placement of radioactive seeds into the prostate by inserting multiple needles into the prostate gland under ultrasound guidance. It is conceivable that the instrumentation of the prostate during the seed placement provides a vascular access for tumor cells from trauma to blood vessels. This iatrogenic dissemination of tumor cells can potentially cause metastatic foci to develop that may subsequently lead to systemic failure. RT-PCR techniques can be used to identify PSA prostate positive epithelial cells. In this study, we determine the extent of the problem of iatrogenic tumor cell dissemination during the brachytherapy procedure, using PSA as a marker by RT-PCR analysis. Thirty one prostate cancer patients who underwent brachytherapy procedure were recruited in this study. Four subjects who underwent prostate biopsy for prostate cancer diagnosis were used as case controls. Four normal males and one normal female were used as negative controls. Ten cc of peripheral blood was collected before, during and after brachytherapy procedure. Mononuclear cells were isolated by Ficoll-hypaque technique using CPT^TM cell preparation vacutainer tube. Total RNA was isolated and ³²P-RT-PCR was performed using radiolabeled specific primers for PSA and G6PDH genes. All the four case controls were negative for PSA mRNA before and after biopsy procedure. All the 4 normal males and a female were negative for PSA expression. Out of 31 patients, 3 (9.67%) were positive for PSA expression before the treatment. Seventeen out of 31(54.8%) were positive for PSA during the brachytherapy. And, 18 out of 31(58.06%) patients were positive after one hour of brachytherapy treatment procedure. Interestingly, 13 out of 31(41.9%) patients who were negative before the treatment turned positive during and after the therapy. These data is currently being correlated with clinical end-points to understand the impact of this iatrogenic shedding on prognosis. These findings strongly suggest that iatrogenic shedding caused by brachytherapy procedure may increase the risk of metastatic deposits and systemic failure.

KEYWORDS: prostate cancer, PSA, RT-PCR, brachytherapy