Evaluation of nuclear factor κB and chemokine receptor CXCR4 co-expression in patients with prostate cancer in the Radiation Therapy Oncology Group (RTOG) 8610

OBJECTIVE

To determine the frequency of nuclear factor κB (NFκB) and the chemokine receptor CXCR4 co-expression in prostate cancer specimens from men with locally advanced disease.

PATIENTS AND METHODS

Paraffin-embedded samples from patients enrolled on the Radiation Therapy Oncology Group (RTOG) 8610 trial underwent immunohistochemical staining for NFκB and CXCR4. The amount of NFκB and CXCR4 was scored by a 'blinded' pathologist for the percentage of cells stained (0-100%) and staining intensity (0-3 +). Cox proportional hazard models were used for overall survival and disease-free survival to examine if NFκB and/or CXCR4 expression were associated with patient outcomes with and without adjustment for covariates.

RESULTS

Available material and successful staining allowed NFκB and CXCR4 status to be determined for 55 and 63 patients, respectively. Both NFκB and CXCR4 status were available for 51 patients. Of these, 53% were 2/3 + for cytoplasmic NFκB staining and 56% were 2/3 + for CXCR4. In all, 18 of the 51 patients were 2/3 + for both NFκB and CXCR4 (P = 0.129). Ten of 11 patients with 3 + NFκB had 2/3 + CXCR4 (P= 0.004). In this small study, neither NFκB nor CXCR4 were associated with prostate cancer outcomes.

CONCLUSIONS

High NFκB expression is associated with CXCR4 expression and they are co-expressed in about one third of patients with clinically localized prostate cancer. Larger studies to accurately determine the frequency of co-expression and prognostic utility of NFκB and CXCR4 alone and in combination are warranted.

Phase II trial of combined high-dose-rate brachytherapy and external beam radiotherapy for adenocarcinoma of the prostate: preliminary results of RTOG 0321

PURPOSE

To estimate the rate of late Grade 3 or greater genitourinary (GU) and gastrointestinal (GI) adverse events (AEs) after treatment with external beam radiotherapy and prostate high-dose-rate (HDR) brachytherapy.

METHODS AND MATERIALS

Each participating institution submitted computed tomography-based HDR brachytherapy dosimetry data electronically for credentialing and for each study patient. Patients with locally confined Stage T1c-T3b prostate cancer were eligible for the present study. All patients were treated with 45 Gy in 25 fractions using external beam radiotherapy and one HDR implant delivering 19 Gy in two fractions. All AEs were graded according to the Common Terminology Criteria for Adverse Events, version 3.0. Late GU/GI AEs were defined as those occurring >9 months from the start of the protocol treatment, in patients with ≥18 months of potential follow-up.

RESULTS

A total of 129 patients from 14 institutions were enrolled in the present study. Of the 129 patients, 125 were eligible, and AE data were available for 112 patients at analysis. The pretreatment characteristics of the patients were as follows: Stage T1c-T2c, 91%; Stage T3a-T3b, 9%; prostate-specific antigen level ≤10 ng/mL, 70%; prostate-specific antigen level >10 but ≤20 ng/mL, 30%; and Gleason score 2-6, 10%; Gleason score 7, 72%; and Gleason score 8-10, 18%. At a median follow-up of 29.6 months, three acute and four late Grade 3 GU/GI AEs were reported. The estimated rate of late Grade 3-5 GU and GI AEs at 18 months was 2.56%.

CONCLUSION

This is the first prospective, multi-institutional trial of computed tomography-based HDR brachytherapy and external beam radiotherapy. The technique and doses used in the present study resulted in acceptable levels of AEs.

Impact of ultrahigh baseline PSA levels on biochemical and clinical outcomes in two Radiation Therapy Oncology Group prostate clinical trials

PURPOSE

To assess ultrahigh (UH; prostate-specific antigen [PSA] levels ≥50 ng/ml) patient outcomes by comparison to other high-risk patient outcomes and to identify outcome predictors.

METHODS AND MATERIALS

Prostate cancer patients (PCP) from two Phase III Radiation Therapy Oncology Group clinical trials (studies 9202 and 9413) were divided into two groups: high-risk patients with and without UH baseline PSA levels. Predictive variables included age, Gleason score, clinical T stage, Karnofsky performance score, and treatment arm. Outcomes included overall survival (OS), distant metastasis (DM), and biochemical failure (BF). Unadjusted and adjusted hazard ratios (HRs) were calculated using either the Cox or Fine and Gray's regression model with associated 95% confidence intervals (CI) and p values.

RESULTS

There were 401 patients in the UH PSA group and 1,792 patients in the non-UH PSA PCP group of a total of 2,193 high-risk PCP. PCP with UH PSA were found to have inferior OS (HR, 1.19; 95% CI, 1.02-1.39, p = 0.02), DM (HR, 1.51; 95% CI, 1.19-1.92; p = 0.0006), and BF (HR, 1.50; 95% CI, 1.29-1.73; p < 0.0001) compared to other high-risk PCP. In the UH cohort, PSA level was found to be a significant factor for the risk of DM (HR, 1.01; 95% CI, 1.001-1.02) but not OS and BF. Gleason grades of 8 to 10 were found to consistently predict for poor OS, DM, and BF outcomes (with HR estimates ranging from 1.41-2.36) in both the high-risk cohort and the UH cohort multivariable analyses.

CONCLUSIONS

UH PSA levels at diagnosis are related to detrimental changes in OS, DM, and BF. All three outcomes can be modeled by various combinations of all predictive variables tested.

Baseline serum testosterone in men treated with androgen deprivation therapy and radiotherapy for localized prostate cancer

INTRODUCTION

It is believed that men diagnosed with prostate cancer and a low baseline serum testosterone (BST) may have more aggressive disease, and it is frequently recommended they forego testosterone replacement therapy. We used two large Phase III trials involving androgen deprivation therapy and external beam radiation therapy to assess the significance of a BST.

METHODS AND MATERIALS

All patients with a BST and complete data (n = 2,478) were included in this analysis and divided into four categories: "Very Low BST" (VLBST) ≤16.5th percentile of BST (≤248 ng/dL; n = 408); "Low BST" (LBST) >16.5th percentile and ≤33rd percentile (>248 ng/dL but ≤314 ng/dL; n = 415); "Average BST" (ABST) >33rd percentile and ≤67th percentile (314-437 ng/dL; n = 845); and "High BST" (HBST) >67th percentile (>437 ng/dL; n = 810). Outcomes included overall survival, distant metastasis, biochemical failure, and cause-specific survival. All outcomes were adjusted for the following covariates: treatment arm, BST, age (<70 vs. ≥70), prostate-specific antigen (PSA; <10 vs. 10 ≤ PSA <20 vs. 20 ≤), Gleason score (2-6 vs. 7 vs. 8-10); T stage (T1-T2 vs. T3-T4), and Karnofsky Performance Status (60-90 vs. 100).

RESULTS

On multivariable analysis age, Gleason score, and PSA were independently associated with an increased risk of biochemical failure, distant metastasis and a reduced cause-specific and overall survival (p < 0.05), but BST was not.

CONCLUSIONS

BST does not affect outcomes in men treated with external beam radiation therapy and androgen deprivation therapy for prostate cancer.

Confirmation of a low α/β ratio for prostate cancer treated by external beam radiation therapy alone using a post-treatment repeated-measures model for PSA dynamics

PURPOSE

To estimate the α/β ratio of prostate cancer treated with external beam radiation only by use of a model of long-term prostate-specific antigen (PSA) dynamics.

METHODS AND MATERIALS

Repeated measures of PSA from 5,093 patients from 6 institutions treated for localized prostate cancer by external beam radiation therapy (EBRT) without planned androgen deprivation were analyzed. A biphasic linear mixed model described the post-treatment evolution of PSA, rather than a conventional model of time to biochemical recurrence. The model was adjusted for standard prognostic factors (T stage, initial PSA level, and Gleason score) and cohort-specific effects. The radiation dose fractionation effect was estimated from the long-term rate of rise of PSA level.

RESULTS

Adjusted for other factors, total dose of EBRT and sum of squared doses per fraction were associated with long-term rate of change of PSA level (p = 0.0017 and p = 0.0003, respectively), an increase of each being associated with a lower rate of rise. The α/β ratio was estimated at 1.55 Gy (95% confidence band, 0.46-4.52 Gy). This estimate was robust to adjustment of the linear mixed model.

CONCLUSIONS

By analysis of a large EBRT-only cohort along with a method that uses all the repeated measures of PSA after the end of treatment, a low and precise α/β was estimated. These data support the use of hypofractionation at fractional doses up to 2.8 Gy but cannot presently be assumed to accurately represent higher doses per fraction.

Counseling patients about sexual health when considering post-prostatectomy radiation treatment

Prostate cancer is the second most frequently diagnosed cancer in men in the United States. Many men with clinically localized prostate cancer survive for 15 years or more. Although early detection and successful definitive treatments are increasingly common, a debate regarding how aggressively to treat prostate cancer is ongoing because of the effect of aggressive treatment on the quality of life, including sexual functioning. We examined current research on the effect of post-prostatectomy radiation treatment on sexual functioning, and suggest a way in which patient desired outcomes might be taken into consideration while making decisions with regard to the timing of radiation therapy after prostatectomy.

Impact of ultrahigh baseline PSA levels on biochemical and clinical outcomes in two Radiation Therapy Oncology Group (RTOG) prostate clinical trials

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Background: Controversy exists regarding the outcomes of prostate cancer patients (PCP) presenting with ultra-high (UH; defined as PSA ≥ 50 ng/ml) PSA levels. The objectives of this study were to assess the outcome of this patient population compared to other high-risk patients and to identify predictors associated with biochemical/clinical outcomes. Methods: PCP from two phase III RTOG PC clinical trials (9202 and 9413) were divided into two groups; high-risk patients with and without UH baseline PSA level. Predictive variables included age, Gleason score, T stage, KPS, and treatment arm. Outcomes included overall survival (OS), distant metastasis (DM), and biochemical failure (BF) by Phoenix definition. A Cox proportional hazards regression model was used for OS, and Fine and Gray's regression model was used for DM and BF to test the hypotheses that a difference in each outcome exists between the two groups. Results: There are 401 PCP in the UH PSA and 1792 in the non-UH PSA cohort. Median age was 70 years and PCP were evenly distributed across the Gleason groups (2–6, 7, 8–10) for the non-UH (median PSA 22.4 ng/ml) and the UH PSA (median PSA 72.8ng/ml) cohort. The UH PSA cohort had a larger proportion of T1-T2 disease (p = 0.01) and a smaller proportion of Gleason 8 disease (p = 0.04) than the non-UH group. PCP with UH PSA was found to have inferior OS (HR 1.19, 95% CI 1.02–1.39), DM rate (HR 1.51, 95% CI 1.19–1.92), and BF rate (HR 1.50, 95% CI 1.29–1.73) when compared to other high-risk PCP in multivariable modeling. In the UH cohort, PSA level was found to model risk of DM (HR 1.01, 95% CI 1.001–1.02) but not OS and BF. Gleason grade 8–10 was found to consistently predict for poor OS, DM, and BF outcomes (with HR estimates ranging from 1.41 to 2.36) in both the overall and UH cohort multivariable analyses. Conclusions: UH PSA levels at diagnosis are related with detrimental changes in OS, DM, and BF. All three outcomes assessed in this investigation can be modeled by various combinations all predictive variables tested. Supported by RTOG U10 CA21661, CCOP U10 CA37422, and Stat U10 CA32115 grants from the NCI. This abstract's contents are the sole responsibility of the authors and do not necessarily represent the official views of the NCI.

No significant financial relationships to disclose.

Development of RTOG consensus guidelines for the definition of the clinical target volume for postoperative conformal radiation therapy for prostate cancer

PURPOSE

To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer.

METHODS AND MATERIALS

An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary "consensus" PF-CTV.

RESULTS

Starting from the model-derived CTV, consensus was reached for a CT image-based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferens remnant to >8-12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1-2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement.

CONCLUSIONS

Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.

Impact of the duration of adjuvant hormonal therapy in patients with locally advanced prostate cancer treated with radiotherapy: a secondary analysis of RTOG 85-31

PURPOSE

Radiation Therapy Oncology Group 85-31 was a randomized trial of androgen suppression for life for patients with locally advanced prostate cancer. However, not all patients continued on the protocol-mandated long-term hormonal therapy despite no evidence of recurrence. We correlated duration of adjuvant hormonal therapy and outcomes among patients who prematurely discontinued hormonal therapy.

PATIENTS AND METHODS

The protocol mandated pelvic radiotherapy followed by goserelin given indefinitely or until disease progression. There were 189 analyzable patients. Patients were divided in groups based on the tertile of hormonal therapy duration (HTD) as follows: < or = 1 year, more than 1 year and < or = 5 years, and more than 5 years. Overall survival (OS), disease-free survival (DFS), cause-specific mortality, local failure (LF), and distant metastasis (DM) were studied. Kaplan-Meier estimation and Cox proportional hazards regression model were used for OS and DFS, and Fine and Gray's regression model was used for the other outcomes.

RESULTS

The median follow-up for surviving patients is 9.6 years. The median duration of adjuvant hormonal therapy was 2.2 years. The HTD more than 5 years group is significantly associated with an improved survival and DFS and fewer DMs than other HTD groups. After adjustment for age, radical prostatectomy, nodal status, Gleason score, and stage variables, the HTD more than 5 years group remains significantly associated with better OS and DFS than other HTD groups.

CONCLUSION

In this hypothesis-generating analysis, prolonged HTD of more than 5 years seems significantly associated with improvements in most outcomes. Given these data, decreasing HTD to < or = 5 years may have a detrimental effect on patients with locally advanced prostate cancer. Only a randomized trial will conclusively clarify this issue.

Clinical cancer advances 2008: major research advances in cancer treatment, prevention, and screening--a report from the American Society of Clinical Oncology

A message from ASCO'S president: Nearly 40 years ago, President Richard Nixon signed the National Cancer Act, mobilizing the country's resources to make the "conquest of cancer a national crusade." That declaration led to a major investment in cancer research that has significantly improved cancer prevention, treatment, and survival. As a result, two thirds of people diagnosed with cancer today will live at least 5 years after diagnosis, compared with just half in the 1970s. In addition, there are now more than 12 million cancer survivors in the United States--up from 3 million in 1971. Scientifically, we have never been in a better position to advance cancer treatment. Basic scientific research, fueled in recent years by the tools of molecular biology, has generated unprecedented knowledge of cancer development. We now understand many of the cellular pathways that can lead to cancer. We have learned how to develop drugs that block those pathways; increasingly, we know how to personalize therapy to the unique genetics of the tumor and the patient. Yet in 2008, 1.4 million people in the United States will still be diagnosed with cancer, and more than half a million will die as a result of the disease. Some cancers remain stubbornly resistant to treatment, whereas others cannot be detected until they are in their advanced, less curable stages. Biologically, the cancer cell is notoriously wily; each time we throw an obstacle in its path, it finds an alternate route that must then be blocked. To translate our growing basic science knowledge into better treatments for patients, a new national commitment to cancer research is urgently needed. However, funding for cancer research has stagnated. The budgets of the National Institutes of Health and the National Cancer Institute have failed to keep pace with inflation, declining up to 13% in real terms since 2004. Tighter budgets reduce incentives to support high-risk research that could have the largest payoffs. The most significant clinical research is conducted increasingly overseas. In addition, talented young physicians in the United States, seeing less opportunity in the field of oncology, are choosing other specialties instead. Although greater investment in research is critical, the need for new therapies is only part of the challenge. Far too many people in the United States lack access to the treatments that already exist, leading to unnecessary suffering and death. Uninsured cancer patients are significantly more likely to die than those with insurance, racial disparities in cancer incidence and mortality remain stark, and even insured patients struggle to keep up with the rapidly rising cost of cancer therapies. As this annual American Society of Clinical Oncology report of the major cancer research advances during the last year demonstrates, we are making important progress against cancer. But sound public policies are essential to accelerate that progress. In 2009, we have an opportunity to reinvest in cancer research, and to support policies that will help ensure that every individual in the United States receives potentially life-saving cancer prevention, early detection, and treatment. Sincerely, Richard L. Schilsky, MD President American Society of Clinical Oncology.

Prognostic value of survivin in locally advanced prostate cancer: study based on RTOG 8610

PURPOSE

To examine the prognostic value of nuclear and cytoplasmic survivin expression in men with locally advanced prostate cancer who were enrolled in Radiation Therapy Oncology Group (RTOG) protocol 8610.

METHODS AND MATERIALS

RTOG 8610 was a Phase III randomized study comparing the effect of radiotherapy plus short-term androgen deprivation with radiotherapy alone. Of the 456 eligible patients, 68 patients had suitably stained tumor material for nuclear survivin analysis and 65 patients for cytoplasmic survivin.

RESULTS

Compared with patients with nuclear survivin intensity scores of <or=191.2, those with intensity scores >191.2 had significantly improved prostate cancer survival (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.20-1.00, p = 0.0452). On multivariate analysis, nuclear survivin intensity scores >191.2 were significantly associated with improved overall survival (HR, 0.46; 95% CI, 0.25-0.86; p = 0.0156) and prostate cancer survival (HR, 0.36; 95% CI, 0.16-0.84; p = 0.0173). On univariate analysis, compared with patients with cytoplasmic survivin integrated optical density <or=82.7, those with an integrated optical density >82.7 showed a significantly increased risk of local progression (HR, 2.49; 95% CI, 1.03-6.01; p = 0.0421).

CONCLUSION

Nuclear overexpression of survivin was associated with improved overall and prostate cancer survival on multivariate analysis, and cytoplasmic overexpression of survivin was associated with increased rate of local progression on univariate analysis in patients with locally advanced prostate cancer treated on RTOG 8610. Our results might reflect the different functions of survivin and its splice variants, which are known to exist in distinct subcellular compartments.

Variation in the definition of clinical target volumes for pelvic nodal conformal radiation therapy for prostate cancer

PURPOSE

We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group.

METHODS AND MATERIALS

Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition.

RESULTS

Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 +/- 203 for case 1 and 60.3, 627.7, 251.8 +/- 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire.

CONCLUSIONS

Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.