EXPRESSION OF VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) IN LOCALLY INVASIVE PROSTATE CANCER IS PROGNOSTIC FOR RADIOTHERAPY OUTCOME

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1 doi: /j.ijrob Int. J. Radiation Oncology Biol. Phys., Vol. 67, No. 1, , 2007 Coyright 2007 Elsevier Inc. Printed in the USA. All rights reserved /07/$ see front matter CLINICAL INVESTIGATION Prostate EXPRESSION OF VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) IN LOCALLY INVASIVE PROSTATE CANCER IS PROGNOSTIC FOR RADIOTHERAPY OUTCOME MELANIE M. L. GREEN, PH.D.,* CRISPIN T. HILEY, M.B.CH.B., JONATHAN H. SHANKS, M.R.C.PATH., IAN C. BOTTOMLEY, B.A.HONS, CATHARINE M. L. WEST, PH.D., RICHARD A. COWAN, F.R.C.R., AND IAN J. STRATFORD, PH.D.* *Deartment of Pharmacy and Pharmaceutical Sciences, Couland III, University of Manchester, Oxford Road, Manchester, UK; Deartments of Clinical Oncology, Histoathology, and Medical Statistics, and Academic Deartment of Radiation Oncology, The University of Manchester, Christie Hosital NHS Trust, Manchester, UK Purose: Vascular endothelial growth factor (VEGF) is an imortant hyoxia-inducible ro-angiogenic rotein that has been linked with an adverse survival outcome after radiotheray in other cancer tyes: we hyothesized that this may also occur in rostate cancer. A retrosective study was, therefore, carried out to evaluate the otential of tumor VEGF exression to redict radiotheray outcome in atients with high-risk rostate cancer. Methods and Materials: Fifty atients with locally advanced (T3 N0 M0) tumors of Gleason score >6, and who received radiotheray alone as rimary treatment for their disease, were studied. Vascular endothelial growth factor exression was assessed on retreatment diagnostic tumor biosies using a semiquantitative immunohistochemical scoring system. The results were analyzed in relation to clinicoathologic factors and atient outcome including biochemical failure and disease-secific mortality. Results: High VEGF exression was associated with a oor rognosis: in univariate log rank analysis, VEGF was the only significant rognostic factor for disease-secific survival ( 0.035). High VEGF exression also associated with increased Gleason score ( 0.02), but not osttreatment biochemical failure. Conclusion: High tumor exression of VEGF identified atients at high risk of failure of treatment with radiotheray. These atients might benefit from additional treatment aroaches incororating anti-angiogenic or hyoxia-secific agents Elsevier Inc. Vascular endothelial growth factor, Radiotheray, Prostate cancer, Prognosis. INTRODUCTION External beam radical radiotheray remains the rimary treatment of choice for atients with locally advanced and/or high grade rostate tumors in the United States and the United Kingdom (1, 2). Although develoments in radiotheray technique (3, 4) and the recent introduction of adjuvant hormone theray (HT) has imroved survival outcomes for men receiving radiotheray (5 7), a significant roortion of tumors still demonstrate a oor resonse to this treatment modality. Disease recurrence rates after radiotheray are considerable, but vary according to tumor characteristics and endoint studied. For examle, when studying osttreatment biochemical failure (BF) (i.e., raised levels of circulating rostate-secific antigen [PSA]), a 5 year failure rate of 35% was seen in atients with Gleason scores of 6 or above (3). In a randomized trial carried out in men with T2-T4 tumors, the cumulative incidence of local rogression at 5 years was 71%, metastasis incidence was 41%, and rogression-free survival (including normal PSA levels) was 15% (8). In a retrosective study of atients with Gleason scores of 5 7 and 8 10, 5-year metastasis incidence rates of 17% and 42%, resectively, were recorded (9). Recurrence may be controlled by androgen ablative HT, and this may sufficiently extend an elderly atient s lifesan. However, localized hormone-sensitive rostate cancer ultimately rogresses to hormone-resistant, advanced stage disease. Consequently, rostate cancer remains one of the leading causes of cancer death among men in both the United States and the United Kingdom. Note An online CME test for this article can be taken at under Education and Meetings. Rerint requests to: Ian Stratford, Ph.D., Deartment of Pharmacy and Pharmaceutical Sciences, Couland III, University of Manchester, Oxford Road, M13 9PL, Manchester, UK. Tel: ( 44) ; Fax: ( 44) ; ian.j. stratford@manchester.ac.uk Suorted by a grant from the MRC (G ), Cancer Research UK, and NTRAC. Acknowledgments The authors would like to thank Dr. Ric Swindell (Princile Statistician, Deartment of Medical Statistics, The Christie Hosital NHS Trust) for his assistance with the statistical analysis. Conflict of interest: none. Received March 28, 2006, and in revised form Aug 10, Acceted for ublication Aug 29,

2 VEGF and radiotheray outcome in rostate cancer M. M. L. GREEN et al. 85 The ability to redict atients with a high risk of tumor recurrence after radiotheray would be a major advance and enable a greater individualization of treatment. Highrisk atients would be good candidates for clinical trials involving the addition of novel investigational agents, whereas those with a low risk of recurrence could be offered standard radiotheray. Vascular endothelial growth factor (VEGF), an imortant hyoxia-related angiogenesis stimulating factor, has otential as a rognostic factor for radiotheray outcome for rostate cancer, because its exression has been linked with oor rognosis, including adverse outcome after radiotheray, in other tumor tyes (10 13). Vascular endothelial growth factor is a diffusible mitogen that lays a critical role in tumor angiogenesis by increasing blood vessel ermeability, endothelial cell growth, roliferation, migration, and differentiation (14 16). Uregulation of VEGF occurs in resonse to a tumor microenvironment of low oxygen conditions (hyoxia) via the hyoxia-inducible transcrition factor HIF-1 (17). Hyoxia is recognized as a major factor driving malignant rogression, resistance to cancer treatments, and subsequently oor rognosis (18). Exression of VEGF in resonse to hyoxia is key to this rocess and has led to VEGF being defined as the rime hyoxia-inducible angiogenic factor (17, 18). Vascular endothelial growth factor is also induced by a number of cytokine growth factors such as eidermal growth factor, latelet-derived growth factor, basic fibroblast growth factor, and transforming growth factor alha. Mutations in ras oncogenes (19 23) and 53 (22, 23) are also linked with increased VEGF exression, as are genetic alterations of the hoshatase and tensin homolog rotein and the Von Hiel Lindau rotein that increase HIF-1 activity in tumor cells, which may indirectly lead to increased levels of VEGF (24, 25). Overexression of VEGF has been linked to tumor rogression and oor rognosis in many tumor tyes, including colorectal carcinoma (10), gastric carcinoma (12), ancreatic carcinoma (13), and cervix carcinoma (11). High lasma levels of VEGF in rostate cancer have also been associated with oor rognosis (26, 27). Hyoxic regions have been demonstrated in human rostate carcinoma using direct measurements made with Eendorf electrodes and increasing levels of hyoxia associated with more advanced clinical stage (28, 29). Imortantly, revious studies in rostate cancer also demonstrated increasing levels of hyoxia correlated with increased tumor exression of VEGF (29) and redicted BF after radiotheray (30). We, therefore, hyothesized that tumor exression of VEGF may have otential use as a biologic marker of adverse atient outcome after radiotheray for locally advanced rostate cancer. We investigated this retrosectively in atients treated with radiotheray using both BF and rostate cancer-secific mortality (PCSM) as study endoints. METHODS AND MATERIALS Patients Patients were selected from the Christie Hosital rostate cancer atient database using the inclusion criteria: histologically confirmed locally advanced rostate cancer (T3 N0 M0); Gleason score of 6;, and external beam radiotheray as rimary treatment. Patients who received neoadjuvant or adjuvant HT were excluded. Using these criteria, 65 atients were selected who were treated between 1995 and The South Manchester ethics and research committee granted ethical aroval for the study and informed consent was obtained from all atients. Relevant biosy material was only available for 50 of 65 selected atients. Thirty-four of the 50 atient samles were sextant biosy cores obtained transrectally using ultrasound guidance. Only ositive biosy cores consistent with the diagnostic athology reort were used. The remainder of the samles were rostatic chiings obtained during transurethral resection of the rostate. Radiotheray was delivered with high energy linear accelerators using a conventional three-dimensional conformal technique. Multileaf collimation was used to shae the treatment ortal. Radiation was targeted to the rostate gland and included seminal vesicles: nonenlarged regional lymh nodes were not routinely included. The majority of atients (46/50) received 50 Gy in 16 fractions, consistent with the usual standard of the Manchester treatment center. One atient received 52.5 Gy in 20 fractions to a larger treatment field that encomassed a marginally enlarged elvic node (although the atient was staged node negative). The remaining atients received a referred dose of the articular treating clinician: 1 received 47.5 Gy in 16 fractions and 2 received 50 Gy in 20 fractions. Patients were reviewed osttreatment in secialist oncology clinics with regular PSA estimations. The median follow-u time was 64 months (range, months). For surviving atients, the median follow-u time was 68 months (range, months). The end of the follow-u eriod was August Two atient outcome measures, osttreatment BF and PCSM, were studied. Biochemical failure indicating disease relase was defined as a rise in PSA level of 2 ng/ml greater than the ostradiotheray nadir, dated to the failed PSA test. This definition has recently been shown to be articularly secific and more sensitive comared to other definitions of BF (31, 32). Prostate cancer secific death was determined from the death certificate and hosital notes or by ost mortem certificated cause of death. All reorted rostate cancer deaths were further verified as registered cancer deaths by the Centre of Eidemiology, North West Cancer Registry. Assessment of VEGF exression Sections 4 m thick were reared from formalin-fixed, araffin-embedded biosy secimens and were immunostained using a DAKO Envision HRP (DAB) System kit (DakoCytomation Inc, Carinteria, CA). After dearaffination and rehydration, microwave antigen retrieval was erformed in Tris-EDTA solution (0.05M Tris-HCl, M EDTA), followed by quenching endogenous eroxidase using kit reagents. A solution of 10% casein (Vector) in Tris-buffered saline was used to block nonsecific binding before alication of rabbit anti-vegf olyclonal antibody (A-20 sc-152) (Santa Cruz Biotechnology, Santa Cruz, CA) for 30 min at 2 g/ml. Primary antibody was substituted with 2 g/ml nonimmune rabbit immunoglobulin (DakoCytomation Inc.) for negative control sections. Visualization of the rimary antibody was achieved using the eroxidase conjugated anti-rabbit

3 86 I. J. Radiation Oncology Biology Physics Volume 67, Number 1, 2007 Table 2. Univariate log rank analysis of utative rognostic factors for disease secific survival after radical radiotheray for locally advanced rostate cancer Parameter Age (ⱕ68, 68) Gleason Score (6, 7, 8 10) Pretreatment PSA ( 17.5, 17.5) Posttreatment BF (, ) Posttreatment PSA doubling (, ) VEGF (high, low) Disease-secific survival Abbreviations: VEGF vascular endothelial growth factor; PSA rostate-secific antigen; BF biochemical failure. Fig. 1. Immunostaining for vascular endothelial growth factor using DAB stain (brown). Examles of biosies with low (a c) and high (e h) vascular endothelial growth factor scores are shown at 10 and 40 magnification. Figure aears in color online. immunoglobulins, and DAB-based chromogen solution sulied in the kit. Sections were lightly counterstained with Gills hematoxylin, dehydrated, and mounted. Sections from cervix biosies known to stain ositively for VEGF (11), lus strong and weakly stained rostate sections from the receding batch, were run rou- Table 1. Distribution of atients and atient variables according to VEGF exression VEGF Parameter Gleason score Posttreatment biochemical failure ( / ) Posttreatment PSA double ( / ) Age Pretreatment PSA levels Low (0 4) n 22 High (5 8) n 28 (n atients) (n atients) (mean) (mean) value Abbreviations: VEGF vascular endothelial growth factor; PSA rostate-secific antigen. tinely to ensure reroducibility and exclude batch to batch variation. Vascular endothelial growth factor exression was assessed in tumor cells using a reviously ublished semiquantitative scoring method for VEGF exression in rostate tissue blind to atient outcome. The ercentage of ositively stained glands was evaluated (none 0; less than 1% 1, 1 10% 2; 11 33% 3; 34 67% 4; and more than 67% 5) and the staining intensity was assessed (none 0; weak 1; moderate 2; strong 3). The ercentage and intensity scores were added together to give a final immunoreactive score (IRS) of 0 8 (29). Only adenocarcinoma cells consistent with the Gleason grade of the diagnostic athology reort were scored. All areas of benign glands, Prostatic Intraeithelial Neolasia, stromal tissue, inflammatory infiltrates or areas at the edge of a section that had been damaged by biosy or by heat from transurethral resection of the rostate were ignored. The tumor sections were scored twice by the first observer (C.H.) and once by the second observer (M.G.). The biosy sections and scoring methods were additionally reviewed by a consultant athologist (J.S.), who also scored 20 randomly selected biosies. For statistical uroses VEGF IRS scores were categorized according to the median score of 5 (i.e., low VEGF score 5, high VEGF score 5 8). Tyical examles from low and high VEGF scoring categories are shown in Fig. 1. Statistical analysis Analyses were erformed using SPSS version 11.5 with the guidance of The Christie Hosital NHS Trust, Deartment of Medical Statistics. Correlations of scores/variables were obtained using Searman s rank. Chi-squared linear-by-linear association was used to examine the distribution of atients according to VEGF exression and Gleason score; Fishers exact test was used Table 3. Bivariate stratified log rank analyses showing the significance of VEGF exression for disease-secific survival after allowing for the listed arameters Parameter value Gleason score (6, 7, 8 10) Age Pretreatment PSA Posttreatment BF 0.12* Abbreviations: VEGF vascular endothelial growth factor; PSA rostate-secific antigen; BF biochemical failure. * Pooled over strata.

4 VEGF and radiotheray outcome in rostate cancer M. M. L. GREEN et al. 87 to analyze VEGF exression in relation to osttreatment BF and PSA doubling status. The unaired t test and the Mann-Whitney U-test were used to examine VEGF exression in relation to atient age and retreatment PSA level, resectively (Table 1). Patient age and retreatment PSA level were subsequently treated as dichotomous variables for survival analyses (Tables 2 and 3), slit at the median levels of 68 years and 17.5 ng/ml, resectively. Retrosective survival analysis was erformed using the Kalan- Meier method and log rank analysis was carried out to assess the significance of rognostic factors. RESULTS VEGF immunostaining and scoring Positive staining for VEGF exression was seen in 41 rostate biosies (82%). Staining was entirely cytolasmic with no nuclear or membrane staining observed and was largely restricted to secretory cells. Uniform stain intensity was seen within the cells of individual tumor acini, but heterogenous staining was observed between different tumor foci of biosy sections. Some benign eithelium demonstrated ositive staining for VEGF; this was generally weaker than regions of adenocarcinoma and the basal cell layer was stained to a lesser extent than secretory cells. Very occasional scattered lymhoid cells and sindle shaed stromal cells stained weakly. Highly significant correlations (r 0.95, 0.01) were obtained between the intra- and interobserver scores, demonstrating excellent scoring reroducibility. The frequencies for each ossible IRS were: 0 (9), 2 (3), 3 (3), 4 (7), 5 (5), 6 (10), 7 (8), and 8 (5). Distribution of atients and atient variables according to VEGF exression Table 1 summarizes the distribution of atients and atient variables according to tumor VEGF exression. Significantly more atients with tumors of higher Gleason score also had high VEGF exression ( 0.02), but there was no association between VEGF and osttreatment BF or PSA doubling ( 1.0 and 0.56, resectively). There was also no association between high or low VEGF exression and atient age or retreatment PSA level ( 0.1 and 0.95, resectively); this remained the case when VEGF IRS scores (0 8) were correlated with atient age and retreatment PSA levels ( 0.1 and 0.4, resectively). Correlation with outcome Tumor VEGF exression was a significant rognostic factor for rostate cancer-secific mortality (Fig. 2). In univariate log rank analysis (Table 2), only VEGF exression was redictive of disease-secific atient survival after radiotheray ( 0.035). Desite being recognized rognostic factors in rostate cancer in this small atient cohort, Gleason score had a close but nonsignificant association with atient survival ( 0.092), as did osttreatment PSA doubling ( 0.085). In bivariate analysis (Table 3), VEGF Fig. 2. Kalan-Meier survival curve of 50 atients with rostate carcinoma treated with radiotheray and groued according to tumor vascular endothelial growth factor (VEGF) exression. The numbers of atients and disease-related deaths in each arm are indicated. exression retained rognostic significance after allowing for atient age ( 0.049) and osttreatment BF ( 0.40). Borderline significance was obtained after allowing for retreatment PSA levels ( 0.058). Thirty-six of the 50 atients studied demonstrated BF after radiation treatment. Of the 36 atients that failed, 25 subsequently received HT for disease relase. Sixteen of the 50 atients studied demonstrated doubled PSA levels osttreatment; the median PSA doubling time for these atients was 783 days (2.15 years). Only 2 of 16 atients who doubled osttreatment demonstrated doubling times of less than 6 months, and both of these atients died of rostate cancer in less than 2.5 years from treatment. Although both osttreatment BF and PSA doubling status was not associated with atient survival, when Kalan-Meier and log rank analysis was erformed to examine osttreatment PSA doubling time, atients who died secifically of rostate cancer demonstrated significantly reduced PSA doubling times ( 0.01). Vascular endothelial growth factor did not aear to be related to PSA doubling: log rank analysis revealed that VEGF levels did not redict PSA doubling ( 0.46), and for atients who demonstrated doubled PSA levels osttreatment (n 16), there was no correlation between PSA doubling time in days and VEGF IRS (0 8) scores ( 0.93). Nine of the 50 atients died secifically from metastatic rostate cancer. Two other atients died of intercurrent causes. Of the 9 atients who died secifically from rostate cancer, all 9 demonstrated osttreatment BF (although only 5 demonstrated doubled osttreatment PSA levels) and were subsequently treated with HT. All 9 atients, therefore, died of HT-resistant metastatic rostate cancer: 8 of these 9 atients had high retreatment tumor VEGF scores and the remaining atient had a VEGF IRS score of 4, suggesting a link between hormone refractory disease and high VEGF exression.

5 88 I. J. Radiation Oncology Biology Physics Volume 67, Number 1, 2007 Fig. 3. Diagram illustrating the distribution of rostate cancer-secific deaths among the 50 atients studied in relation to tumor Gleason score and vascular endothelial growth factor (VEGF) exression. The atient distribution and disease outcome analyses indicate that tumor VEGF exression may be useful as a rognostic indicator of PCSM after radiotheray in addition to acceted rognostic factors such as Gleason score. Figure 3 illustrates diagrammatically the distribution of rostate cancer-secific deaths among the 50 atients studied in relation to tumor Gleason score and VEGF exression. DISCUSSION Prostate cancer treatment selection is based on tumor stage and grade, PSA status, life exectancy, and is influenced by morbidity risks, atient reference, and clinician s treatment hilosohy. Radical radiotheray (with or without adjuvant HT) remains the rimary treatment of choice for locally advanced rostate cancer, but surgery, HT alone, or watchful waiting may also be considered. However, it is not ossible to identify atients with radiotheray-resonsive disease from atients with a high likelihood of adverse outcome. Therefore, there is a need for cellular or molecular biologic markers that better redict disease rogression and treatment outcome to hel guide treatment decisions and aid the develoment of more effective theraeutic strategies (33). Hyoxia and angiogenesis are known to lay a fundamental role in tumorigenesis and cancer treatment resonse, yet hyoxia, hyoxia-induced radiotheray resistance, and hyoxia-induced angiogenesis have been under-studied in rostate cancer. We have shown in a grou of radiotheraytreated atients that exression of VEGF an imortant hyoxia-related marker of angiogenesis can be used to redict long-term atient treatment resonse. To our knowledge, this is the first study linking tumor exression of VEGF to oor survival after radiotheray in atients with rostate cancer. Previous studies of rostate cancer atient outcome have been comlicated by mixed atient grous of widely variable initial rognosis, inconsistent treatments, and different study endoints. To aid interretation and allow meaningful outcome analysis, only men with relatively equivalent oor rognosis (stage T3 locally advanced disease, Gleason 6), who received standard radical radiotheray only as rimary curative treatment were included in this study. Patients who received neoadjuvant or adjuvant HT were urosely excluded: HT alters the natural history of rostate cancer and modulates the blood suly to the rostate, which could otentially alter the efficacy of radiotheray (5 7, 34) and the hyoxia-regulated exression of VEGF (35). In addition, both disease-secific mortality and BF were analyzed as the rimary and secondary study endoints after longterm atient follow-u. Previous studies have focused solely on BF to measure treatment outcome: BF is a simle-tomeasure surrogate marker of disease rogression, recurrence, or theraeutic resistance that is commonly used to identify treatment failure in the clinic. However, its use as a surrogate marker for rostate cancer morbidity and mortality is contentious and the varied definitions of biochemical failure after radiotheray make BF a controversial endoint marker for failure of treatment (36 41). Indeed, osttreatment BF did not redict atient survival in the cohort of atients studied here, suorting indications that BF is a less reliable redictor of atient survival than reviously thought (32, 36, 39 41). This result was also obtained when the American Society for Theraeutic Radiology and Oncology definition of BF was alied, although a trend was noted for atients with high VEGF to have shorter median time to biochemical failure (18.6 months) comared with atients with low tumor VEGF exression (27.5 months). However, altogether, although retreatment tumor VEGF exression redicted PCSM and PSA doubling time was also linked to PCSM, as reorted by other research grous (42), retreatment tumor VEGF exression aears to be unrelated to PSA secretion indicators, such as retreatment PSA levels, or osttreatment BF/PSA doubling. This suggests that although PSA secretion indicators accomany treatment failure and subsequent death from metastatic rostate cancer,

6 VEGF and radiotheray outcome in rostate cancer M. M. L. GREEN et al. 89 VEGF has an indeendent biologic imact on the efficacy of treatment and likelihood of subsequent PCSM. The association between increased VEGF exression and oor survival may be reflecting tumor hyoxia and, therefore, directly reduced radiosensitivity of tumor cells and subsequent oor local control of tumor by radiation (34). The indirect effects of a hyoxic microenvironment uon tumor cell gene exression may decrease the efficacy of radiotheray because of increased tumor cell metastatic and angiogenic otential. Alternatively, increased metastatic otential of tumor cells might be gained by VEGF exression induced by nonhyoxia related mechanisms (e.g., via cytokine growth factors or ras mutations). Of the 9 rostate cancer atients who died from hormone refractory metastatic disease, 8 had high VEGF scores (5 8) and 1 had a VEGF score of 4. This suggests a otential link between high levels of VEGF and hormone resistance. The develoment of hormone resistance is the normal rogression attern of rostate cancer and the mechanism is oorly understood. Evidence suggests that androgen ablation reduces blood flow to the rostate, causing a hyoxic microenvironment (35, 43). The results resented here suort a role for a hyoxia resistance mechanism in the develoment of hormone resistant rostate cancer, because it is ossible that high VEGF levels may allow tumor cells to adat and survive desite the hormone-induced hyoxic environment. A hyoxia resistance mechanism has reviously been suggested to underlie the transient effectiveness of HT when exerimental data demonstrated two of five human hormone-resistant rostate cancers contained mutations in the oxygen-deendent degradation domain of HIF-1. This could enable inaroriate exression of HIF, and consequent exression of VEGF in some rostate tumors (44, 45). Because treatment otions for men with locally advanced rostate cancer are tyically surgery or radiotheray (with or without adjuvant HT), the results of similar retrosective studies of tumor VEGF exression in men with equivalent initial rognosis who underwent surgery or radiotheray with adjuvant HT as their rimary treatment may hel to rovide guidance when making initial treatment decisions. In addition, studying tumor VEGF exression in atients who received radiotheray with adjuvant HT may hel to further investigate the otential link between tumor VEGF exression and HT resistance. Because VEGF was shown to have rognostic value to redict radiotheray outcome in this small cohort of radiotheray treated atients with highrisk disease, it may subsequently be considered imortant to investigate the rognostic otential of VEGF exression in rostate cancer atients with intermediate-risk disease. Such atients may be offered a broad range of treatments, including radiotheray, and, therefore, have a ressing need for novel redictors of theraeutic resonse to aid clinical decisions. To study PCSM, rather than BF, this would necessitate a large multicenter study to ensure adequate follow-u and sufficient PCSM events. In conclusion, we reort that assessment of high tumor VEGF exression on retreatment diagnostic biosies identified atients at risk of adverse outcome after radiotheray. These atients might benefit from more aggressive radiation treatments or alternative treatment aroaches that incororate antiangiogenic or hyoxia-secific agents. REFERENCES 1. D Amico AV. Combined-modality staging for localized adenocarcinoma of the rostate. Oncology (Williston Park) 2001; 15: The Royal College of Radiologists Clinical Oncology Information Network; British Association of Urological Surgeons. Guidelines on the management of rostate cancer. 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