Deoxyribonucleic acid cytometric analysis of prostate core biopsy specimens: relationship to serum prostate specific antigen and prostatic acid phosphatase, clinical stage and histopathology

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Prediction of pathologic stage and postprostatectomy disease recurrence by DNA ploidy analysis of initial needle biopsy specimens of prostate cancer

BACKGROUND

DNA ploidy determination of carcinomas in radical prostatectomy specimens has shown significant correlation with patient outcome, but the predictive value of ploidy status of cancers obtained by transrectal ultrasound-guided needle biopsies has not been studied extensively.

METHODS

Eighty-nine paired needle biopsy specimens (NBX) and radical prostatectomy (RPX) specimens from patients with early clinical stage (A2-B2) prostate cancer were evaluated for DNA content by image analysis of Feulgen stained tissue sections. Findings were compared with Gleason grading on the same specimens by univariate and multivariate analyses for prediction of local tumor invasion, metastasis, disease recurrence, and serum prostate specific antigen concentration during a 0.9-6.0 year clinical follow-up period.

RESULTS

There was excellent correlation of ploidy status between NBX and RPX specimens (P < 0.0001); NBX and RPX grades did not correlate. On RPX specimens, aneuploid status correlated with high tumor grade (P < 0.0005). Aneuploidy in NBX specimens was associated with a twofold higher rate of extracapsular spread (ECS) (P = 0.04). Aneuploid NBX tumors featured a tenfold greater frequency of metastasis than did diploid NBX tumors (P < 0.005). Radical prostatectomy grade correlated with ECS (P < 0.001) and presence of metastatic disease (P = 0.04). On multivariate logistic regression analysis, aneuploidy in both NBX and RPX specimens was the most significant variable and independently predicted the presence of metastasis (P = 0.006 for NBX; P = 0.028 for RPX). Tumor grade of NBX and RPX specimens did not independently predict metastatic disease or disease recurrence, but RPX grade was associated independently with ECS (P = 0.005). Aneuploid NBX tumors recurred after RPX three times more often than did diploid cases, which was significant on univariate (P < 0.001) and multivariate (P = 0.018) analyses using the Cox proportional hazards model. There was no correlation with NBX or RPX Gleason score and disease recurrence. Preoperative serum PSA concentration did not correlate with tumor grade or ploidy status, but on multivariate analysis, when paired with ploidy status, independently contributed to the propensity for ECS, metastasis, and disease recurrence.

CONCLUSIONS

DNA content analysis of early clinical stage prostate carcinoma needle biopsy specimens by image analysis directly correlates with radical prostatectomy specimen ploidy status and is associated independently, with the presence of metastasis, postprostatectomy disease recurrence, and ECS. Needle biopsy tumor grading did not correlate with prostatectomy grade and did not predict disease outcome accurately.

Flow Cytometry Role of DNA Analysis

We analyzed the results obtained by flow cytometry DNA analysis in prostatic cancer. We considered the diagnostic role of this investigation and the prognostic value observed from correlating the DNA analysis with usual diagnostic and prognostic factors such as staging, grading, PSA, size, etc. Results in literature suggest that further studies are necessary to explain both the biological and cytometrical heterogeneous aspects of this neoplasm.

The prognostic significance of DNA ploidy in clinically localized prostate cancer treated with radiation therapy

PURPOSE

To determine the prognostic significance of deoxyribonucleic acid (DNA) ploidy in comparison to pretreatment prostate specific antigen (PSA) and other prognostic factors for patients with adenocarcinoma of the prostate treated with external beam radiotherapy.

METHODS AND MATERIALS

Paraffin-embedded prostatic adenocarcinoma material was obtained from patients treated from 1987-1991. Sufficient histologic material for flow cytometric DNA content analysis was obtained from 86 patients and adequate histograms were obtained from 76 of these. The DNA histogram profiles were classified as diploid, tetraploid, or aneuploid. Median patient follow-up was 36 months.

RESULTS

There were 54 patients with diploid tumors, and 22 with nondiploid tumors (11 tetraploid and 11 aneuploid). Since the disease outcome for tetraploid and aneuploid tumors was the same, these were pooled (nondiploid tumors). The distribution of diploidy and nondiploidy correlated with pretreatment PSA (p < 0.0005) and grade (p = 0.055), but not with stage, pretreatment prostatic acid phosphatase, transurethral resection, pretreatment serum testosterone, or age. In actuarial univariate analyses, DNA ploidy was a significant predictor of outcome for local failure, distant metastases, any clinical relapse, rising PSA, and rising PSA and/or relapse. Ploidy was not a significant predictor of overall survival, although there were only six deaths. Diploidy predicted for improved outcome, for example, 34.6% incidence of a rising PSA and/or relapse at 4 years compared to 76.9% with nondiploidy (p < 0.0001). An actuarial univariate analysis of other potential prognostic factors using the composite endpoint of rising PSA and/or relapse also revealed pretreatment PSA, grade, pretreatment prostatic acid phosphatase, stage, and serum testosterone to be significant predictors of outcome. In Cox proportional hazards analysis, pretreatment PSA, DNA ploidy, and grade were the only independent prognostic factors for disease outcome using the composite endpoint.

CONCLUSION

DNA ploidy is an independent predictor of outcome in patients with Stages T1-T3 prostate cancer treated with definitive external beam radiotherapy.