Near-diploidy: a new prognostic factor for clinically localized prostate cancer treated with external beam radiation therapy

In Treating Localized Prostate Cancer the Efficacy of Cryoablation is Independent of DNA Ploidy Type

While the prognostic value of DNA ploidy has been well established for radical prostatectomy, external beam radiation, brachytherapy and androgen deprivation therapy its role as a survival outcome predictor for prostate cancer patients treated with cryoablation has not yet been examined. Anecdotal evidence suggesting that cryoablation may be independent of DNA ploidy type led to the implementation of the current study. Retrospective analysis of data including flow digital cytometry was performed on 447 archival specimens taken from patients who had undergone cryosurgical ablation of primary prostate cancer. Five-year biochemical disease free survivals (bDFS) (defined as PSA thresholds of 0.5 and 1.0 ng/ml) were determined with Kaplan-Meier analysis. Patients were grouped according to DNA ploidy types then stratified by Gleason grade, risk group, pre-surgical PSA level, and disease stage.

Mean and median age of the cohort was 65 and 64.6 years. Mean follow-up was 65.7 months. The DNA ploidy status of the population was found to be 59% diploid, 13% tetraploid, and 28% aneuploid. Using PSA < 1.0 ng/ml criterion, the bDFS rates for diploid, tetraploid, and aneuploid were 78%, 75%, and 79% respectively. The bDFS rates using a PSA < 0.5 ng/ml criterion were 67%, 59%, and 69% for diploid, tetraploid, and aneuploid groups. No significant outcome differences were found in stratified analysis. This investigation demonstrates that the efficacy of cryoablation is independent of DNA ploidy type.

Genomic and Histopathological Tissue Biomarkers That Predict Radiotherapy Response in Localised Prostate Cancer

Localised prostate cancer, in particular, intermediate risk disease, has varied survival outcomes that cannot be predicted accurately using current clinical risk factors. External beam radiotherapy (EBRT) is one of the standard curative treatment options for localised disease and its efficacy is related to wide ranging aspects of tumour biology. Histopathological techniques including immunohistochemistry and a variety of genomic assays have been used to identify biomarkers of tumour proliferation, cell cycle checkpoints, hypoxia, DNA repair, apoptosis, and androgen synthesis, which predict response to radiotherapy. Global measures of genomic instability also show exciting capacity to predict survival outcomes following EBRT. There is also an urgent clinical need for biomarkers to predict the radiotherapy fraction sensitivity of different prostate tumours and preclinical studies point to possible candidates. Finally, the increased resolution of next generation sequencing (NGS) is likely to enable yet more precise molecular predictions of radiotherapy response and fraction sensitivity.

An arranged marriage for precision medicine: hypoxia and genomic assays in localized prostate cancer radiotherapy

Prostate cancer (CaP) is the most commonly diagnosed malignancy in males in the Western world with one in six males diagnosed in their lifetime. Current clinical prognostication groupings use pathologic Gleason score, pre-treatment prostatic-specific antigen and Union for International Cancer Control-TNM staging to place patients with localized CaP into low-, intermediate- and high-risk categories. These categories represent an increasing risk of biochemical failure and CaP-specific mortality rates, they also reflect the need for increasing treatment intensity and justification for increased side effects. In this article, we point out that 30-50% of patients will still fail image-guided radiotherapy or surgery despite the judicious use of clinical risk categories owing to interpatient heterogeneity in treatment response. To improve treatment individualization, better predictors of prognosis and radiotherapy treatment response are needed to triage patients to bespoke and intensified CaP treatment protocols. These should include the use of pre-treatment genomic tests based on DNA or RNA indices and/or assays that reflect cancer metabolism, such as hypoxia assays, to define patient-specific CaP progression and aggression. More importantly, it is argued that these novel prognostic assays could be even more useful if combined together to drive forward precision cancer medicine for localized CaP.

Tissue biomarkers for prostate cancer radiation therapy

Prostate cancer is the most common cancer and second leading cause of cancer deaths among men in the United States. Most men have localized disease diagnosed following an elevated serum prostate specific antigen test for cancer screening purposes. Standard treatment options consist of surgery or definitive radiation therapy directed by clinical factors that are organized into risk stratification groups. Current clinical risk stratification systems are still insufficient to differentiate lethal from indolent disease. Similarly, a subset of men in poor risk groups need to be identified for more aggressive treatment and enrollment into clinical trials. Furthermore, these clinical tools are very limited in revealing information about the biologic pathways driving these different disease phenotypes and do not offer insights for novel treatments which are needed in men with poor-risk disease. We believe molecular biomarkers may serve to bridge these inadequacies of traditional clinical factors opening the door for personalized treatment approaches that would allow tailoring of treatment options to maximize therapeutic outcome. We review the current state of prognostic and predictive tissue-based molecular biomarkers which can be used to direct localized prostate cancer treatment decisions, specifically those implicated with definitive and salvage radiation therapy.

RAD51 can inhibit PDGF-B-induced gliomagenesis and genomic instability

Faithful replication and DNA repair are vital for maintenance of genome integrity. RAD51 is a central protein in homologous recombination repair and during replication, when it protects and restarts stalled replication forks. Aberrant RAD51 expression occurs in glioma, and high expression has been shown to correlate with prolonged survival. Furthermore, genes involved in DNA damage response (DDR) are mutated or deleted in human glioblastomas, corroborating the importance of proper DNA repair to suppress gliomagenesis. We have analyzed DDR and genomic instability in PDGF-B-induced gliomas and investigated the role of RAD51 in glioma development. We show that PDGF-B-induced gliomas display genomic instability and that co-expression of RAD51 can suppress PDGF-B-induced tumorigenesis and prolong survival. Expression of RAD51 inhibited proliferation and genomic instability of tumor cells independent of Arf status. Our results demonstrate that the RAD51 pathway can prevent glioma initiation and maintain genome integrity of induced tumors, suggesting reactivation of the RAD51 pathway as a potential therapeutic avenue.

Characteristics of prostate cancers detected at low PSA levels

BACKGROUND

When age-referenced PSA levels as recommended by Oesterling et al.1 were used as a biopsy criterion, only 25% of the cancers detected in a population based PSA Screening Project were organ-confined. This observation led to the decision to use low PSA levels as the sole indication for biopsy. Since 1995 age-referenced PSA levels of 1.25-3.25 ng/ml have been used in combination with a percentage free PSA cutoff of 18%. This PSA cutoff reduction led to a statistically significant migration to lower pathological stages with a decreased prostate cancer mortality in the years 1996-2001. However, concerns have been raised that screening with low PSA levels may detect clinically insignificant cancers.

MATERIALS AND METHODS

We evaluated prostate cancer patients with low PSA levels in terms of heterogeneity, clinical significance, multifocality, and tumor biology including ploidy and proliferation index.

RESULTS

Concerning heterogeneity the Gleason score of the needle biopsy failed to predict the Gleason score of the radical prostatectomy specimen in nearly 40% of prostate cancer patients; regarding multifocality 65% of patients with low PSA levels showed multifocal lesions and 36% exhibited tetraploid DNA distribution; more than 50% of tetraploid tumors were found in patients with tumor volumes of less than 0.5 cm(3). Ploidy correlated with the Ki-67 proliferation index, but not with tumor volume.

CONCLUSIONS

These results demonstrate that small prostate cancers with low PSA levels and low tumor volumes exhibit all features of prostate cancers with higher tumor volumes and show the characteristics of malignant cancers, i.e., multifocality, tetraploidy, and high proliferative activity.

Prostate cancer DNA ploidy and response to salvage hormone therapy after radiotherapy with or without short-term total androgen blockade: an analysis of RTOG 8610

PURPOSE

DNA ploidy has consistently been found to be a correlate of prostate cancer patient outcome. However, a minority of studies have used pretreatment diagnostic material and have involved radiotherapy (RT)-treated patients. In this retrospective study, the predictive value of DNA ploidy was evaluated in patients entered into Radiation Therapy Oncology Group protocol 8610. The protocol treatment randomization was RT alone versus RT plus short-course (approximately 4 months) neoadjuvant and concurrent total androgen blockade (RT+TAB).

PATIENTS AND METHODS

The study population consisted of 149 patients, of whom 74 received RT alone and 75 received RT+TAB. DNA content was determined by image analysis of Feulgen stained tissue sections; 94 patients were diploid and 55 patients were nondiploid. Kaplan-Meier univariate survival, the cumulative incidence method, and Cox proportional hazards multivariate analyses were used to evaluate the relationship of DNA ploidy to distant metastasis and overall survival.

RESULTS

DNA nondiploidy was not associated with any of the other prognostic factors in univariate analyses. In Kaplan-Meier analyses, 5-year overall survival was 70% for those with diploid tumors and 42% for nondiploid tumors. Cox proportional hazards regression revealed that nondiploidy was independently associated with reduced overall survival. No correlation was observed between DNA ploidy and distant metastasis. The diminished survival in the absence of an increase in distant metastasis was related to a reduction in the effect of salvage androgen ablation; patients treated initially with RT+TAB and who had nondiploid tumors had reduced survival after salvage androgen ablation.

CONCLUSIONS

Nondiploidy was associated with shorter survival, which seemed to be related to reduced response to salvage hormone therapy for those previously exposed to short-term TAB.

Fluorescence in situ hybridization aneuploidy as a predictor of clinical disease recurrence and prostate-specific antigen level 3 years after radical prostatectomy

OBJECTIVE

To determine if fluorescence in situ hybridization (FISH) analysis of fresh-tissue biopsy specimens obtained at the time of radical prostatectomy is able to predict prospectively clinical disease progression or prostate-specific antigen (PSA) level in patients 3 to 4 years after surgery.

MATERIALS AND METHODS

FISH analysis was performed on fresh-tissue touch preparations obtained from 90 randomly selected radical prostatectomy specimens. Cut surface touch preparations from 40 specimens resected in 1992 were analyzed with DNA probes for chromosomes 4, 6-12, 17, 18, X, and Y. Needle-biopsy specimens were obtained from 50 tumors resected in 1993, and touch preparations from these specimens were studied with DNA probes for chromosomes 7, 8, 11, and 12. Serum PSA levels and clinicopathologic data were recorded, and each patient was followed up from the time of surgery to determine cancer progression.

RESULTS

Of 90 patients undergoing radical prostatectomy in 1992 and 1993, 89 returned for follow-up. Three patients received preoperative hormonal therapy, and in 2 patients, antiandrogen therapy was continued postoperatively. Fifteen patients underwent intraoperative orchiectomy immediately after radical prostatectomy, while 9 patients had postoperative adjuvant hormonal therapy. Six patients underwent postoperative radiation therapy. Fourteen patients (15.7%) demonstrated systemic, local, or PSA progression. Only 2 (4.7%) of 43 patients with FISH diploid tumors demonstrated cancer progression. Conversely, 10 (30.3%) of 33 FISH aneuploid and 12 (26.1%) of 46 FISH nondiploid tumors demonstrated cancer progression (P=.004 and P=.006, respectively). Unlike FISH, flow cytometric aneuploidy was not associated with early cancer progression. Elevated preoperative PSA concentration, increased preoperative and postoperative Gleason score, and increased preoperative and postoperative T or N stage were not statistically significantly associated with cancer progression. While chromosome 7 and 8 aneusomies were not statistically associated with cancer progression, 2 of 5 (P=.04) chromosome 12 aneusomic tumors demonstrated cancer progression.

CONCLUSION

Early (within 4 years) local, systemic, or PSA progression occurred more frequently (P<.05) in radical prostatectomy patients with FISH aneuploid, nondiploid, and chromosome 12 aneusomic tumors. Flow cytometric ploidy status, preoperative serum PSA concentration, and clinical or pathologic grade or stage, including seminal vesicle involvement, margin status, and capsular perforation status, were not associated with early prostate cancer progression in this group of 89 patients. FISH analysis appears to be a useful preoperative tool for predicting aggressive vs indolent prostate cancer.

Needle biopsy DNA ploidy status predicts grade shifting in prostate cancer

DNA ploidy analysis of prostate needle biopsy specimens was performed to determine whether ploidy status could predict tumor grade shifting at radical prostatectomy. The paired needle biopsy and radical prostatectomy specimens from 111 randomly selected men with prostate cancer were obtained from the surgical pathology files of the Albany Medical Center Hospital. The original tumor grades were assigned by a staff of 12 surgical pathologists according to the Gleason system. Tumors with original Gleason scores < or = 6 were classified as low grade, and tumors with scores of > or = 7 were considered high grade. DNA ploidy analysis was performed on the needle biopsy specimens using the CAS 200 image analyzer (Becton Dickinson Immunocytometry Systems, Mountain View, CA, USA) on Feulgen stained 5-microm tissue sections. There were 88 diploid and 23 nondiploid cases. Thirty-eight of 111 (34%) of cases had grade shifting from needle biopsy to radical prostatectomy specimens. Of 89 low-grade needle biopsy cases, 28 (31%) were upgraded at radical prostatectomy. Of 22 high-grade needle biopsy cases, 10 (45%) were downgraded to low grade at radical prostatectomy. Of the 28 low-grade needle biopsy specimens that were upgraded at radical prostatectomy, 19 (68%) featured an aneuploid histogram and 9 (32%) were diploid. Nineteen of 28 (68%) of aneuploid low-grade tumors on needle biopsy became high-grade at radical prostatectomy. Nine of 10 (90%) diploid high-grade tumors at needle biopsy became low-grade at radical prostatectomy. Of the 38 cases in which ploidy and grade were incongruous, 28 (74%) had grade shifting. In a multivariate regression analysis, a high-grade Gleason score on radical prostatectomy specimens correlated significantly with needle biopsy ploidy (p = 0.0001) but not with needle biopsy grade (p = 0.15). The sensitivity of the needle biopsy grade in the detection of high-grade tumors on radical prostatectomy was 30%, and the specificity was 86%. The sensitivity of ploidy status in the prediction of high grade at radical prostatectomy was 78%, and the specificity was 96%. With a prostate-specific antigen (PSA) level of >0.4 ng/ml as the indicator of post-radical prostatectomy disease recurrence on a subset of 106 patients, on univariate analysis, disease recurrence was predicted by needle biopsy ploidy (p = 0.001) and radical prostatectomy grade (p = 0.04) but not by needle biopsy grade (p = 0.39). On multivariate analysis, needle biopsy DNA ploidy status independently predicted disease recurrence (p = 0.002), whereas needle biopsy and prostatectomy grade did not. These results indicate that DNA ploidy analysis of needle biopsy specimens of prostate cancer predicts grade shifting, that it is a more sensitive and specific indicator of final tumor grade at radical prostatectomy than is the original needle biopsy grade, and that ploidy status independently predicts postoperative disease recurrence.

S-phase fraction related to prognosis in localised prostate cancer. No specific significance of chromosome 7 gain or deletion of 7q31.1

A flow-cytometric (FCM) and fluorescence in situ hybridization (FISH) study was performed in 153 patients with clinically localised prostate cancer (PC) to evaluate retrospectively the prognostic significance of DNA ploidy, S-phase fraction (SPF) and chromosome 7 copy number. Deletions in 7q31.1 were analysed in a subset of 26 tumours. The mean follow-up time was 6 years (range 4-16 years). Twelve cases of benign prostatic hyperplasia (BPH) were studied as a control. Chromosome 7 enumeration and deletion studies were conducted using the alpha-satellite D7Z1 probe and a cosmid probe specific for the marker D7S522 on 7q31.1. Higher SPF was associated with shorter overall survival and shorter time to local progression and metastasis. Near diploid (DNA index 1.05-1.20) cases had a lower frequency of metastases and lower Gleason scores than aneuploid cases. Increased absolute chromosome 7 copy number (centromere count) was associated with higher Gleason score, higher SPF and shorter local progression-free and prostate cancer survival. Absolute chromosome 7 copy number was concordant with FCM DNA ploidy in the majority (75%) of cases. Relative gain or loss of chromosome 7 (centromere counts compared to ploidy) was infrequent, and no correlation was found with clinical parameters. Deletions in 7q31.1 were infrequent. Our results indicate that in localised PC (i) SPF is a prognostic factor, (ii) absolute chromosome 7 copy number is concordant with the ploidy status of the tumour (relative gain or loss of chromosome 7 is infrequent and has no independent prognostic value) and (iii) the frequency of deletions in 7q31.1 is low and not correlated with clinical outcome.

DNA ploidy and survival of patients with clinically localized prostate cancer treated without intent to cure

BACKGROUND

The optimal approach to diagnosis and treatment of localized prostate cancer remains controversial. Deoxyribonucleic acid (DNA) ploidy has been suggested as an important predictor for outcome in prostate cancer. The purpose of this study was to correlate DNA ploidy with disease-specific survival in patients with clinically localized prostate cancer treated with no intent to cure.

METHODS

DNA ploidy was determined by flow cytometry in archival formalin fixed, paraffin embedded tumor tissue obtained at diagnosis in 120 patients with clinically localized prostate cancer with a nearly complete follow-up.

RESULTS

Ninety (75%) of the tumors were diploid, while only 11 (9%) tumors were categorized as tetraploid. Tumor DNA ploidy (diploid versus nondiploid) significantly associated with histopathological grade (P=0.002) and disease-specific survival (P=0.011), while there was no association with tumor stage (P=0.054). In a multivariate Cox analysis, histopathological grade (P=0.005) was the only significant predictor of disease-specific death, while analyzing the 96 low-grade tumors separately, DNA ploidy became significant (P= 0.024).

CONCLUSIONS

Flow cytometric determined nondiploidy was associated with disease-specific death in patients with clinically localized prostate cancer, but DNA ploidy provided additional prognostic information in patients with low-grade tumors only.

The significance of DNA-ploidy and S-phase fraction in node-positive (stage D1) prostate cancer treated with androgen ablation

BACKGROUND

The prognostic significance of primary tumor DNA-ploidy and S-phase fraction (SPF) was evaluated in patients treated with androgen ablation for regionally localized node-positive prostate cancer.

METHODS

All patients were diagnosed with lymph node involvement by pelvic lymphadenectomy between 1984 and 1992 and were treated only with androgen ablation. Median follow-up was 45 months. Adequate material for DNA/nuclear protein flow cytometric analysis was available in 33 patients.

RESULTS

The tumors were classified as diploid in 11, near-diploid in 4, tetraploid in 10, and aneuploid in 8 cases. Grouping the patients by nonaneuploidy (diploid and near-diploid and tetraploid) and aneuploidy revealed actuarial 4-year disease progression rates of 14 and 48% (log-rank, P = 0.04), and overall survival rates of 100 and 61% (P = 0.008); however, biochemical progression (rising prostate-specific antigen profile) rates were similar at around 70%. In contrast, SPF was not significantly related to any of the endpoints tested. Several other potential prognostic factors were examined and none correlated significantly with disease progression or survival.

CONCLUSIONS

The biochemical progression rates for patients with nonaneuploid and aneuploid tumors were comparable and high, while the disease progression rates were higher and survival rates lower for those with aneuploid tumors. These data indicate that the lead time from biochemical to disease progression and death was shorter with aneuploidy. That these relationships were observed in such a small patient population attest to the strength of DNA-ploidy as a prognostic factor in this cohort.

DNA ploidy analysis of mucinous cystic tumors of the pancreas. Correlation of aneuploidy with malignancy and poor prognosis

BACKGROUND

Benign and malignant pancreatic mucinous tumors differ in proliferative activity, production of tumor markers, and expression of growth factors. DNA ploidy is a useful index of aggressiveness and poor survival in ductal adenocarcinoma, but has not been studied in pancreatic cystic tumors.

METHODS

The DNA ploidy status of Fuelgen-stained tissue sections of pancreatic mucinous cystic tumors was evaluated by image cytometry and related to clinical outcome obtained by case record review.

RESULTS

Ploidy status correlated with malignancy and poor clinical outcome. All benign mucinous cystadenomas (n = 13) were diploid and cured by resection. Patients with diploid cystadenocarcinomas (n = 6) had an 83% survival rate following resection, while patients with aneuploid cystadenocarcinomas (n = 5) all died (four of disease and the fifth of another cause). The difference in survival between the diploid and aneuploid carcinomas was significant (P = 0.04).

CONCLUSIONS

DNA ploidy status of pancreatic mucinous tumors by image analysis provides quantifiable information that may be predictive of clinical outcome. DNA aneuploidy appears to be a significant differential factor in pancreatic mucinous tumors and is associated with shortened survival in mucinous cystadenocarcinomas.

Flow-cytometry DNA analysis (FCM) in multiple tissue samples of 69 patients with prostatic cancer treated by radical prostatectomy

We subjected 322 tissue samples of 69 patients with prostatic cancer treated by radical prostatectomy to flow-cytometry DNA analysis. From 1 to 8 tissue samples were analysed for all patients: results showed diploidy in 272 cases and aneuploidy in 50 cases. 45 tumours were classified as diploid, and 24 aneuploid. Aneuploid tumours had one or more aneuploid samples, but in no one case were all specimens of the same neoplasm aneuploid. Aneuploidy status could also change in the same tumour. In conclusion, the study shows that prostatic cancer is often heterogeneous with regard to DNA content and that just one specimen cannot be considered representative of the tumour.

Prostate-specific antigen and radiation therapy for clinically localized prostate cancer

PURPOSE

This study was undertaken to: (a) define the prognostic significance of pretreatment serum prostate-specific antigen (PSA) levels in localized prostate cancer treated with radiation; (b) define the prognostic usefulness of postradiation PSA levels; (c) evaluate the outcome of radiation using PSA as an endpoint.

METHODS AND MATERIALS

Disease outcome in 707 patients with Stages T1 (205 men), T2 (256 men), T3 (239 men), and T4 (7 men), receiving definitive external radiation as sole therapy, was evaluated using univariate and multivariate techniques.

RESULTS

At a mean follow-up of 31 months, 157 patients (22%) developed relapse or a rising PSA. Multivariate analysis revealed pretreatment PSA level to be the most significant prognostic factor, with lesser though significant contributions due to Gleason grade (2-6 vs. 7-10) and transurethral resection in T3/T4 disease. The following four prognostic groupings were defined: group I, PSA < or = 4 ng/ml, any grade; group II, 4 < PSA < or = 20, grades 2-6; group III, 4 < PSA < or = 20, grades 7-10; group IV, PSA > 20, any grade. Five-year actuarial relapse rates in these groups were: I, 12%; II, 34%; III, 40%; and IV, 81%. Posttreatment nadir PSA was an independent determinant of outcome and only patients with nadir values < 1 ng/ml fared well (5-year relapse rate 20%). Using rising PSA as an endpoint the 461 patients with T1/T2 disease had an actuarial freedom from disease rate of 70% at 5 years, which appeared to plateau, suggesting that many were cured. No plateau was evident for T3/T4 disease.

CONCLUSION

Pretreatment serum PSA is the single most important predictor of disease outcome after radiation for local prostate cancer. Tumor grade has a lesser though significant prognostic role. Postirradiation nadir PSA value during the first year is a sensitive indicator of response to treatment. Only nadir values < 1 ng/ml are associated with a favorable outlook. A significant fraction of men with T1/T2 disease may be cured with radiation. There was no evidence for a cured fraction among patients with T3/T4 disease.

Frequency and characterization of p53 mutations in clinically localized prostate cancer

OBJECTIVES

To determine the frequency of abnormal p53 expression and to characterize confirmed p53 mutations in tumors from patients with clinically localized adenocarcinoma of the prostate.

METHODS

p53 protein nuclear accumulation was determined immunohistochemically in the initial diagnostic tumor specimens from 37 patients with clinically localized prostate carcinoma. Two primary antibodies were used on all specimens. Structural analysis of the p53 gene was performed using the methods of polymerase chain reaction (PCR)/single-strand conformation polymorphism (SSCP) and DNA sequencing.

RESULTS

In 1 of the 37 (2.7%) tumor specimens, intense p53 nuclear staining was demonstrated using either antibody PAb 1801 or CM-1. The staining in this case was heterogeneous, with approximately 40% of tumor nuclei staining for p53. This tumor specimen was microdissected and DNA was extracted. Following PCR amplification, abnormally migrating bands were noted on SSCP analysis of exon 8. DNA sequencing confirmed the mutation as a C-->A transversion in codon 281 (asp-->glu). PCR/SSCP analysis of exons 5 through 8 was also performed for seven additional tumors that were negative for p53 nuclear accumulation by immunohistochemical (IHC) methods. All of these specimens demonstrated wild-type p53.

CONCLUSIONS

The results of this study confirm and extend our previous findings that p53 mutations are rare in clinically localized adenocarcinoma of the prostate. In detecting clonal p53 mutations, standard immunohistochemical technique correlates reliably with structural p53 gene analysis of the evolutionary conserved domains encompassing exons 5-8. Importantly, most reports have demonstrated that p53 mutations detected by IHC are a late step in the progression of prostate cancer and are associated with advanced disease, dedifferentiation, and the acquisition of androgen independence.

Significance of tumor angiogenesis in clinically localized prostate carcinoma treated with external beam radiotherapy

OBJECTIVES

To determine the prognostic significance of microvessel density (a measure of tumor angiogenesis) in comparison with other prognostic factors for patients with clinically localized prostatic carcinoma treated with external beam radiotherapy.

METHODS

Microvessel density was quantified within the initial invasive carcinoma from the diagnostic transurethral resection specimen of 25 patients with a mean follow-up of 44 months. Microvessels were identified by immunohistochemical staining of endothelial cells for factor VIII-related antigen in formalin-fixed, paraffin-embedded tissue. Microvessels were counted in a x200 field (0.754 mm2) in the area of maximal angiogenesis.

RESULTS

Microvessel density correlated with several pretreatment prognostic factors, including prostate-specific antigen (PSA) (p < 0.0001), tumor grade (p = 0.006), and ploidy (p = 0.016). The degree of tumor angiogenesis also correlated with outcome following external beam radiotherapy. The mean microvessel count in the nine tumors from patients who failed radiotherapy (ie, had rising PSA and/or clinical relapse) was 97.0 +/- 33.6 (+/- SD) per x200 field compared with 46.1 +/- 17.1 for the 16 patients with no evidence of failure (p < 0.0001). Increased microvessel density was also associated with a significantly worse actuarial outcome at 4 years using either biochemical relapse (rising PSA) or a composite endpoint of rising PSA or clinical relapse (p = 0.0003).

CONCLUSIONS

The intratumoral quantification of tumor angiogenesis may prove valuable as a prognostic indicator in patients with clinically localized prostate cancer treated with radiotherapy.

Relationship of tumor DNA-ploidy to serum prostate-specific antigen doubling time after radiotherapy for prostate cancer

OBJECTIVES

DNA-ploidy is a strong prognostic factor for prostate cancer patients treated with definitive external beam radiotherapy. Using DNA/nuclear protein flow cytometry, three prognostic groups based on DNA-ploidy were identified: from good to poor, these are diploid, near-diploid, and nondiploid tumors. Since recent evidence indicates that the rate at which prostate-specific antigen (PSA) increases in the presence of biochemical failure is predictive of the time to clinical relapse, we examined the relationship between DNA-ploidy and PSA doubling time (PSA-DT).

METHODS

Formalin-fixed paraffin-embedded tissues from 76 patients treated at M.D. Anderson Cancer Center with definitive radiotherapy alone were analyzed for ploidy using DNA/nuclear protein flow cytometry. Of these, 24 of the 27 patients with a rising PSA profile had three or more post-treatment PSA values from which the PSA-DTs were calculated. PSA-DTs were estimated using nonlinear regression techniques.

RESULTS

The average PSA-DT for the 24 patients in this cohort was 11.3 +/- 10.5 months (+/- SD) with a median of 8.4 months. Diploidy (n = 3) was associated with a PSA-DT of 27.0 +/- 22.8 months, near-diploidy (n = 7) with a PSA-DT of 12.2 +/- 5.7 months, and non-diploidy (n = 14) with a PSA-DT of 7.5 +/- 5.7 months (p = 0.004, Spearman rank test). Stage, grade, and pretreatment PSA, as well as the endpoints of local control, freedom from metastases, and freedom from any relapse, did not correlate significantly with PSA-DT values. However, when patients were subdivided by PSA-DT into those with values 10 months or less (n = 14) and those more than 10 months (n = 10), there was a correlation with 3-year actuarial freedom from relapse: 28% and 74%, respectively (p < 0.01, log-rank). This subdivision of PSA-DT also correlated with DNA-ploidy (p = 0.03, chi-square) and stage (p = 0.04).

CONCLUSIONS

The results show that there is a significant correlation of DNA-ploidy with PSA-DT. Diploidy was associated with the longest PSA-DTs, near-diploidy with intermediate PSA-DTs, and nondiploidy with short PSA-DTs. Patients with short PSA-DTs also had significantly higher actuarial rates of disease relapse at 3 years. These data confirm that PSA-DT is a strong predictor of tumor behavior and that patients who have nondiploid tumors probably require more aggressive, combined modality, treatment.