To update eligibility and outcome measures in trials that evaluate systemic treatment for patients with progressive prostate cancer and castrate levels of testosterone.
A committee of investigators experienced in conducting trials for prostate cancer defined new consensus criteria by reviewing previous criteria, Response Evaluation Criteria in Solid Tumors (RECIST), and emerging trial data.
The Prostate Cancer Clinical Trials Working Group (PCWG2) recommends a two-objective paradigm: (1) controlling, relieving, or eliminating disease manifestations that are present when treatment is initiated and (2) preventing or delaying disease manifestations expected to occur. Prostate cancers progressing despite castrate levels of testosterone are considered castration resistant and not hormone refractory. Eligibility is defined using standard disease assessments to authenticate disease progression, prior treatment, distinct clinical subtypes, and predictive models. Outcomes are reported independently for prostate-specific antigen (PSA), imaging, and clinical measures, avoiding grouped categorizations such as complete or partial response. In most trials, early changes in PSA and/or pain are not acted on without other evidence of disease progression, and treatment should be continued for at least 12 weeks to ensure adequate drug exposure. Bone scans are reported as “new lesions” or “no new lesions,” changes in soft-tissue disease assessed by RECIST, and pain using validated scales. Defining eligibility for prevent/delay end points requires attention to estimated event frequency and/or random assignment to a control group.
PCWG2 recommends increasing emphasis on time-to-event end points (ie, failure to progress) as decision aids in proceeding from phase II to phase III trials. Recommendations will evolve as data are generated on the utility of intermediate end points to predict clinical benefit.
A prognostic model that predicts overall survival (OS) for metastatic urothelial cancer (MetUC) patients treated with cisplatin-based chemotherapy was developed, validated, and compared with a commonly used Memorial Sloan-Kettering Cancer Center (MSKCC) risk-score model. Data from 7 protocols that enrolled 308 patients with MetUC were pooled. An external multi-institutional dataset was used to validate the model. The primary measurement of predictive discrimination was Harrell’s c-index, computed with 95% confidence interval (CI). The final model included four pretreatment variables to predict OS: visceral metastases, albumin, performance status, and hemoglobin. The Harrell’s c-index was 0.67 for the four-variable model and 0.64 for the MSKCC risk-score model, with a prediction improvement for OS (the U statistic and its standard deviation were used to calculate the two-sided P = .002). In the validation cohort, the c-indices for the four-variable and the MSKCC risk-score models were 0.63 (95% CI = 0.56 to 0.69) and 0.58 (95% CI = 0.52 to 0.65), respectively, with superiority of the four-variable model compared with the MSKCC risk-score model for OS (the U statistic and its standard deviation were used to calculate the two-sided P = .02).
Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a surface receptor on activated T cells that delivers an inhibitory signal, serving as an immune checkpoint. Treatment with anti-CTLA-4 antibodies can induce clinical responses to different malignancies, but the nature of the induced antigen-specific recognition is largely unknown. Using microarrays spotted with over 8000 human proteins, we assessed the diversity of antibody responses modulated by treatment with CTLA-4-blockade and granulocyte macrophage colony-stimulating factor (GM-CSF). We find that advanced prostate cancer patients who clinically respond to treatment also develop enhanced antibody responses to a higher number of antigens than non-responders. These induced antibody responses targeted antigens to which preexisting antibodies are more likely to be present in the clinical responders compared to non-responders. The majority of antibody responses are patient-specific, but immune responses against antigens shared among clinical responders are also detected. One of these shared antigens is p21-activated kinase 6 (Pak6), which is expressed in prostate cancer and to which CD4+ T cell responses were also induced. Moreover, immunization with Pak6 can be both immunogenic and protective in mouse tumor models. These results demonstrate that immune checkpoint blockade modulates antigen-specific responses to both individualized and shared antigens, some of which can mediate anti-tumor responses.
Frequent PSA testing in screening and monitoring of prostate cancer has led to significant stage migration. We evaluated if overall survival (OS) in hormone naïve, metastatic prostate cancer patients has improved during the era of PSA use. We also assessed whether any subsets of patients benefited differentially during this period.
Materials and Methods
We compared OS in three sequential phase III trials of men with hormone naïve, metastatic prostate cancer receiving similar androgen deprivation therapy (n=3096): two conducted prior to the ‘PSA era’ (S8494 and S8894), and the other during this era (S9346). OS was adjusted for patient and disease risk factors in the latter two trials. Subgroups were evaluated by interactions of risk factors with trial.
Median OS in S8494 was 30 months, 33 months in S8894; and 49 months in S9346. Adjusting for risk factors, there was a 22% lower risk of death in S9346 compared to S8894 (hazard ratio 0.78, 95% confidence interval 0.70, 0.87, p<0.001). The improvement in OS was greater in African Americans (AA) (p=0.008 for test of interaction). In both S8494 and S8894, median survival for AA was 27 months and 34 and 35 months for non-AA, respectively; this racial difference disappeared in S9346 (AA OS=48 months, non-AA OS=49 months).
Adjusting for risk factors, OS was significantly improved in the post-PSA era trial. However, attributing this solely to PSA monitoring cannot be concluded. AA men now have comparable OS to Caucasians. Current estimates of survival should be used for designing new trials in this population.
Abiraterone is an oral inhibitor of CYP17, essential for androgen biosynthesis. This multicenter study assessed its efficacy in patients with CRPC without prior exposure to chemotherapy or CYP17 targeted therapy, and assessed the frequency of interpretation of bone scans discordant with PSA and clinical response.
Patients and Methods
33 patients received abiraterone acetate 1000 mg daily with prednisone 5 mg twice daily in continuous 28-day cycles. Patients were evaluated monthly for efficacy and safety. Bone scan flare was defined as the combination, after 3 months of therapy, of an interpreting radiologist's report indicating “disease progression” in the context of a ≥50% decline in PSA, with scan improvement 3 months later.
A ≥ 50% PSA decline at week 12 was confirmed in 22/33 (67%) patients. PSA declines of ≥ 50% were seen in 26 (79%) patients. Undetectable PSA levels (≤ 0.1 ng/mL) occurred in 2 patients. Median time on therapy and time to PSA progression are 63 and 71 weeks, respectively. Twenty three patients were evaluable for bone scan flare. Progression was indicated in the radiologist's report in 12/23 (52 %), and 10/12 subsequently showed improvement. As prospectively defined, bone scan flare was observed in 10/23 (43.5%) evaluable patients or 10/33 (30%) enrolled patients. Adverse events were typically grade 1/2 and consistent with prior published abiraterone reports.
Clinical response to abiraterone acetate plus prednisone was frequent and durable in men with metastatic CRPC progressing on hormonal therapy with over half of patients on therapy > 1 year. Further investigation is needed to clarify the potential confounding effect of the frequently occurring bone scan flare phenomena on patient management and interpretation of clinical trial results.
abiraterone acetate; castration-resistant prostate cancer; CRPC; hormone-resistant prostate cancer; therapy; efficacy
A randomized, placebo-controlled study based on preclinical and clinical data that supports the potential role of vascular endothelial growth factor in prostate cancer was performed to evaluate the addition of bevacizumab to standard docetaxel and prednisone therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).
Patients and Methods
Patients with chemotherapy-naive progressive mCRPC with Eastern Cooperative Oncology Group performance status ≤ 2 and adequate bone marrow, hepatic, and renal function were randomly assigned to receive docetaxel 75 mg/m2 intravenously (IV) over 1 hour for 21 days plus prednisone 5 mg orally twice per day (DP) with either bevacizumab 15 mg/kg IV every 3 weeks (DP + B) or placebo. The primary end point was overall survival (OS), and secondary end points were progression-free survival (PFS), 50% decline in prostate-specific antigen, objective response (OR), and toxicity.
In total, 1,050 patients were randomly assigned. The median OS for patients given DP + B was 22.6 months compared with 21.5 months for patients treated with DP (hazard ratio, 0.91; 95% CI, 0.78 to 1.05; stratified log-rank P = .181). The median PFS time was superior in the DP + B arm (9.9 v 7.5 months, stratified log-rank P < .001) as was the proportion of patients with OR (49.4% v 35.5%; P = .0013). Grade 3 or greater treatment-related toxicity was more common with DP + B (75.4% v 56.2%; P ≤ .001), as was the number of treatment-related deaths (4.0% v 1.2%; P = .005).
Despite an improvement in PFS and OR, the addition of bevacizumab to docetaxel and prednisone did not improve OS in men with mCRPC and was associated with greater toxicity.
Combined transperineal prostate brachytherapy (TPPB) and external beam radiation (EBRT) is widely used for treatment of prostate cancer. Long-term efficacy and toxicity results of a multicenter Phase II trial assessing combination of EBRT and TPPB boost with androgen deprivation therapy (ADT) for intermediate-risk prostate cancer are presented.
Intermediate-risk patients per MSKCC/NCCN criteria received six months of ADT, 45 Gy EBRT to the prostate and seminal vesicles, followed by TPPB with I125(100 Gy) or Pd103(90 Gy). Toxicity was graded using NCI CTC version 2 and RTOG late radiation morbidity scoring systems. Disease free survival (DFS) was defined as time from enrollment to progression (biochemical, local, distant or prostate cancer death). In addition to the protocol definition of biochemical failure (3 consecutive PSA rises >1.0ng/ml after 18 months from treatment start), the 1997 ASTRO consensus and Phoenix definitions were also assessed in defining DFS. The Kaplan-Meier method was used to estimate DFS and overall survival.
61/63 enrolled patients were eligible. Median follow-up was 73 months. Late grade 2 and 3 toxicity, excluding sexual dysfunction, occurred in 20% and 3% of patients. Six year DFS applying the protocol definition, 1997 ASTRO consensus, and Phoenix definitions was 87.1%, 75.1%, and 84.9%. 6 deaths occurred, only one was attributed to prostate cancer. 6 year overall survival was 96.1%.
In a cooperative setting, combination of EBRT and TPPB boost plus ADT resulted in excellent DFS with acceptable late toxicity for patients with intermediate-risk prostate cancer.
prostate; brachytherapy; radiation; cooperative group trial; hormonal therapy
Squamous cell carcinoma of the penis represents approximately 0.5% of all cancers among men in the United States and other developed countries. Although rare, it is associated with significant disfigurement, and only half of the patients survive beyond 5 years. Proper evaluation of both the primary lesion and lymph nodes is critical, because nodal involvement is the most important factor of survival. The NCCN Clinical Practice Guidelines in Oncology for Penile Cancer provide recommendations on the diagnosis and management of this devastating disease based on evidence and expert consensus.
In 2005, the US Department of Defense, through the US Army Medical Research and Materiel Command, Office of the Congressionally Directed Medical Research Programs, created a funding mechanism to form a clinical trials consortium to conduct phase I and II studies in prostate cancer. This is the first report of the Prostate Cancer Clinical Trials Consortium (PCCTC).
Patients and Methods
The Department of Defense award supports a consortium of 10 prostate cancer research centers. Memorial Sloan-Kettering Cancer Center was awarded the Coordinating Center grant for the consortium and charged with creating an infrastructure to conduct early-phase multicenter clinical trials. Each participating center was required to introduce ≥ 1 clinical trial per year and maintain accrual of a minimum of 35 patients per year.
The PCCTC was launched in 2006 and now encompasses 10 leading prostate cancer research centers. Fifty-one trials have been opened, and 1386 patients have been accrued at member sites. Members share an online clinical trial management system for protocol tracking, electronic data capture, and data storage. A legal framework has been instituted, and standard operating procedures, an administrative structure, editorial support, centralized budgeting, and mechanisms for scientific review are established.
The PCCTC fulfills a congressional directive to create a clinical trials instrument dedicated to early-phase prostate cancer studies. The member institutions have built an administrative, informatics, legal, financial, statistical, and scientific infrastructure to support this endeavor. Clinical trials are open and accruing in excess of federally mandated goals.
Clinical consortium; Collaborative; Infrastructure; Phase I/II trial
The use of docetaxel prolongs survival for patients with castrate resistant prostate cancer (CRPC). Inhibition of vascular endothelial growth factor (VEGF) with bevacizumab may further enhance the anti-tumor effect of docetaxel and estramustine in patients with CRPC.
Patients and Methods
This cooperative group trial enrolled men with CRPC. Patients received oral estramustine 280 mg three times per day on days 1-5 of every cycle, with 70 mg/m2 of docetaxel and bevacizumab at 15 mg/kg on day 2, every three weeks. PSA values were monitored every cycle and imaging was performed every 3 cycles. The primary endpoint was progression free survival (PFS) with safety, prostate specific antigen decline, measurable disease response, and overall survival secondary objectives.
Seventy-nine patients were enrolled; 77 received a median of 8 cycles and were evaluable. A 50% PSA decline was observed in 58 patients (75%). Twenty-three of 39 patients with measurable disease had a partial response (59%) The median time of PFS was 8.0 months with an overall median survival of 24 months. Neutropenia without fever (69%), fatigue (25%), thrombosis\emboli (9%) were the most common severe toxicities. Twenty-four of 77 patients were removed from protocol treatment due to disease progression, 35/77 for physician or patient decision and 15 patients secondary to toxicity.
The combination of docetaxel, estramustine and bevacizumab was tolerable but complicated by toxicity. Although progression free survival did not meet the desired endpoint, encouraging anti-tumor activity and overall survival was observed. Further phase III evaluation of the role of bevacizumab in CRPC is ongoing.
Docetaxel; Bevacizumab; castrate resistant prostate cancer
Bevacizumab is an antibody that binds vascular endothelial growth factor and has activity in metastatic renal cell carcinoma (RCC). Interferon alfa (IFN-α) is the historic standard initial treatment for RCC. A prospective, randomized, phase III trial of bevacizumab plus IFN-α versus IFN-α monotherapy was conducted.
Patients and Methods
Patients with previously untreated, metastatic clear cell RCC were randomly assigned to receive either bevacizumab (10 mg/kg intravenously every 2 weeks) plus IFN-α (9 million units subcutaneously three times weekly) or the same dose and schedule of IFN-α monotherapy in a multicenter phase III trial. The primary end point was overall survival (OS). Secondary end points were progression-free survival (PFS), objective response rate, and safety.
Seven hundred thirty-two patients were enrolled. The median OS time was 18.3 months (95% CI, 16.5 to 22.5 months) for bevacizumab plus IFN-α and 17.4 months (95% CI, 14.4 to 20.0 months) for IFN-α monotherapy (unstratified log-rank P = .097). Adjusting on stratification factors, the hazard ratio was 0.86 (95% CI, 0.73 to 1.01; stratified log-rank P = .069) favoring bevacizumab plus IFN-α. There was significantly more grade 3 to 4 hypertension (HTN), anorexia, fatigue, and proteinuria for bevacizumab plus IFN-α. Patients who developed HTN on bevacizumab plus IFN-α had a significantly improved PFS and OS versus patients without HTN.
OS favored the bevacizumab plus IFN-α arm but did not meet the predefined criteria for significance. HTN may be a biomarker of outcome with bevacizumab plus IFN-α.
Abiraterone acetate is a prodrug of abiraterone, a selective inhibitor of CYP17, the enzyme catalyst for two essential steps in androgen biosynthesis. In castration-resistant prostate cancers (CRPCs), extragonadal androgen sources may sustain tumor growth despite a castrate environment. This phase I dose-escalation study of abiraterone acetate evaluated safety, pharmacokinetics, and effects on steroidogenesis and prostate-specific antigen (PSA) levels in men with CPRC with or without prior ketoconazole therapy.
Patients and Methods
Thirty-three men with chemotherapy-naïve progressive CRPC were enrolled. Nineteen patients (58%) had previously received ketoconazole for CRPC. Bone metastases were present in 70% of patients, and visceral involvement was present in 18%. Three patients (9%) had locally advanced disease without distant metastases. Fasted or fed cohorts received abiraterone acetate doses of 250, 500, 750, or 1,000 mg daily. Single-dose pharmacokinetic analyses were performed before continuous daily dosing.
Adverse events were predominantly grade 1 or 2. No dose-limiting toxicities were observed. Hypertension (grade 3, 12%) and hypokalemia (grade 3, 6%; grade 4, 3%) were the most frequent serious toxicities and responded to medical management. Confirmed ≥ 50% PSA declines at week 12 were seen in 18 (55%) of 33 patients, including nine (47%) of 19 patients with prior ketoconazole therapy and nine (64%) of 14 patients without prior ketoconazole therapy. Substantial declines in circulating androgens and increases in mineralocorticoids were seen with all doses.
Abiraterone acetate was well tolerated and demonstrated activity in CRPC, including in patients previously treated with ketoconazole. Continued clinical study is warranted.
To explore whether progression-free survival (PFS) or biochemical PFS can be used as a predictor of overall survival (OS) and to investigate the dependence between PFS and OS in men with castrate-resistant prostate cancer.
Patients and Methods
Data from nine Cancer and Leukemia Group B trials that enrolled 1,296 men from 1991 to 2004 were pooled. Men were eligible if they had prostate cancer that had progressed during androgen deprivation therapy and did not receive prior treatment with chemotherapy, immunotherapy, or other nonhormonal therapy. Landmark analyses of PFS at 3 and 6 months from randomization/registration were performed to minimize lead time bias. The proportional hazards model was used to assess the significance effect of PFS rate at 3 and at 6 months in predicting OS. In addition, biochemical progression using the definitions of Prostate-Specific Antigen Working Group (PSAW) Criteria PSAWG1 and PSAWG2 were analyzed as time-dependent covariates in predicting OS.
The median survival time among men who experienced progression at 3 months was 9.2 months (95% CI, 8.0 to 10.0 months) compared with 17.8 months in men who did not experience progression at 3 months (95% CI, 16.2 to 20.4 months; P < .0001). Compared with men who did not progress at 3 and at 6 months, the adjusted hazard ratios for death were 2.0 (95% CI, 1.7 to 2.4; P < .001) and 1.9 (95% CI, 1.6 to 2.4; P < .001) for men who experienced progression at 3 and 6 months, respectively. In addition, biochemical progression at 3 months predicted OS. The association between PFS and OS was 0.30 (95% confidence limits = 0.26, 0.32).
PFS at 3 and 6 months and biochemical progression at 3 months predict OS. These observations require prospective validation.
Mitoxantrone plus prednisone and ixabepilone each have modest activity as second-line chemotherapy in docetaxel-refractory castration-resistant prostate cancer (CRPC) patients. Clinical noncrossresistance was previously observed.
Patients and Methods
Metastatic CRPC patients progressing during or after taxane-based chemotherapy enrolled in a phase I multicenter study of ixabepilone and mitoxantrone administered every 21 days along with prednisone. Ixabepilone and mitoxantrone doses were alternately escalated in a standard 3 + 3 design. Patients were evaluated for toxicity and disease response. Dose-limiting toxicities (DLTs) were defined as treatment related, occurring during cycle 1, and included grade 4 prolonged or febrile neutropenia, thrombocytopenia (grade 4 or grade 3 with bleeding), or ≥ grade 3 nonhematologic toxicity.
Thirty-six patients were treated; 59% of patients experienced grade 3/4 neutropenia. DLTs included grade 3 diarrhea (n = 1), prolonged grade 4 neutropenia (n = 4), and grade 5 neutropenic infection (n = 1). Due to prolonged neutropenia, the highest dose levels were repeated with pegfilgrastim on day 2 of each cycle. The maximum tolerated dose in combination with pegfilgrastim was not exceeded. The recommended phase II dose is mitoxantrone 12 mg/m2 and ixabepilone 35 mg/m2 every 21 days, pegfilgrastim 6 mg subcutaneously day 2, and continuous prednisone 5 mg twice per day. Thirty-one percent of patients have experienced ≥ 50% prostate-specific antigen (PSA) declines, and two experienced objective responses. Of 21 patients treated with mitoxantrone 12 mg/m2 plus ixabepilone ≥ 30 mg/m2, nine (43%) experienced ≥ 50% PSA declines (95% CI, 22% to 66%).
These results suggest that the combination of ixabepilone and mitoxantrone is feasible and active in CRPC and requires dosing with pegfilgrastim.
Prostate-specific antigen progression (PSA-P) is an indicator of progression in hormone-sensitive (HS) and castration-resistant (CR) prostate cancer (PC). We evaluated different definitions of PSA-P as predictors of overall survival (OS).
Patients and Methods
A total of 1,078 patients with HSPC who were on hormones (Southwest Oncology Group [SWOG] trial 9346 [S9346]) and 597 patients with CRPC who were treated with chemotherapy (SWOG trial 9916 [S9916]) were eligible for this analysis. PSA-P definitions tested included the following: PSA Working Group, Prostate Cancer Working Group (PCWG 2008), and other definitions. A time-varying approach analyzed associations between PSA-P at any time and OS. A landmark analysis examined the relationship between PSA-P status at 7 months for S9346, or 3 months for S9916, and subsequent OS.
In the time-varying analysis, both working groups definitions were strongly associated with OS (P < .001) in both study settings. In patients enrolled onto S9346, both definitions predicted a 2.4-fold increased risk of death (ROD) and a greater than four-fold increased ROD if PSA-P occurred in the first 7 months. In S9916, they predicted a 40% increase in ROD and a two-fold increase in ROD if PSA-P occurred at 3 months. In landmark analyses of patients on S9346 by using the PCWG 2008 definition of PSA-P, median subsequent OS was 10 months versus 44 months in patients who did or did not have PSA-P by 7 months, respectively; in S9916, data were 11 months versus 18 months for patients who did or did not have PSA-P by 3 months, respectively.
PSA-P, defined as an increase of ≥ 25% greater than the nadir and an absolute increase of at least 2 or 5 ng/mL, predicts OS in HSPC and CRPC and may be a suitable end point for phase II studies in these settings.
Bevacizumab is an antibody that binds to vascular endothelial growth factor (VEGF) and has activity in metastatic renal cell carcinoma (RCC). Interferon alfa (IFN) is a historic standard first-line treatment for RCC. A prospective, randomized phase III trial of bevacizumab plus IFN versus IFN monotherapy was conducted.
Patients and Methods
Patients with previously untreated, metastatic clear-cell RCC were randomly assigned to receive either bevacizumab (10 mg/kg intravenously every 2 weeks) plus IFN (9 million U subcutaneously three times weekly) or the same dose and schedule of IFN monotherapy in a multicenter phase III trial. The primary end point was overall survival (OS). Secondary end points were progression-free survival (PFS), objective response rate (ORR), and safety.
Between October 2003 and July 2005, 732 patients were enrolled. The prespecified stopping rule for OS has not yet been reached. The median PFS was 8.5 months in patients receiving bevacizumab plus IFN (95% CI, 7.5 to 9.7 months) versus 5.2 months (95% CI, 3.1 to 5.6 months) in patients receiving IFN monotherapy (log-rank P < .0001). The adjusted hazard ratio was 0.71 (95% CI, 0.61 to 0.83; P < .0001). Bevacizumab plus IFN had a higher ORR as compared with IFN (25.5% [95% CI, 20.9% to 30.6%] v 13.1% [95% CI, 9.5% to 17.3%]; P < .0001). Overall toxicity was greater for bevacizumab plus IFN, including significantly more grade 3 hypertension (9% v 0%), anorexia (17% v 8%), fatigue (35% v 28%), and proteinuria (13% v 0%).
Bevacizumab plus IFN produces a superior PFS and ORR in untreated patients with metastatic RCC as compared with IFN monotherapy. Toxicity is greater in the combination therapy arm.
Abiraterone acetate, an androgen biosynthesis inhibitor, improves overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC) post-chemotherapy. Many mCRPC patients never receive chemotherapy and thus cannot benefit from abiraterone acetate; we evaluated this agent in mCRPC patients who had not received chemotherapy.
In this double-blind study, 1088 patients were randomized 1:1 to abiraterone acetate (1000 mg) plus prednisone (5 mg twice daily) or placebo plus prednisone. Co-primary end points were radiographic progression-free survival (rPFS) and OS. Secondary end points measured clinically relevant landmarks of mCRPC progression. Patient-reported outcomes included pain progression and quality of life.
The study was unblinded after a planned interim analysis (IA) at 43% of OS events. Treatment with abiraterone acetate-prednisone resulted in a 57% reduction in the risk of radiographic progression or death (hazard ratio [HR], 0.43; 95% confidence interval [CI]: 0.35 to 0.52; P<0.001; 13% OS events IA) and an estimated 25% decrease in the risk of death (HR, 0.75; 95% CI: 0.61 to 0.93; P=0.009; 43% OS events IA). Secondary end points supported superiority of abiraterone acetate-prednisone: time to cytotoxic chemotherapy initiation, opiate use for cancer-related pain, prostate-specific antigen progression (all P<0.001) and performance status deterioration (P=0.005). Self-reported time to pain progression and patient functional status degradation favored abiraterone acetate-prednisone (P=0.05 and P=0.003). Grade 3/4 mineralocorticoid-related adverse events and liver function test abnormalities were more common with abiraterone acetate-prednisone.
Abiraterone acetate produces OS and rPFS benefits, as well as significant delays in clinical deterioration and initiation of chemotherapy, in mCRPC.
Abiraterone acetate; prednisone; metastatic castration-resistant prostate cancer; androgen; CYP17
We prospectively determined whether the change in tumor volume (TV) during 2 months of neoadjuvant androgen suppression therapy (nAST) measured using conventional 1.5 Tesla endorectal magnetic resonance imaging (eMRI) was associated with the risk of recurrence after radiation (RT) and 6 months of AST.
Patients and Methods
Between 1997 and 2001, 180 men with clinical stage T1c-T3cN0M0 adenocarcinoma of the prostate were registered. Fifteen were found to be ineligible and the institutional MR radiologist could not assess the TV in 32, leaving 133 for analysis. Multivariable Cox regression analysis was used to assess whether a significant association existed between eMRI-defined TV progression during nAST and time to recurrence adjusting for prostate-specific antigen (PSA) level, Gleason score (8 to 10 or 7 vs. 6 or less) and stage (T3 vs. T1-2).
After a median follow up of 6.7 years and adjusting for known prognostic factors, there was a significant increase in the risk of PSA failure (HR, 2.3 [95% CI, 1.1–4.5; p = 0.025) in men with eMRI-defined TV progression during nAST. Specifically, adjusted estimates of PSA failure were significantly higher (p = 0.032) in men with, compared with men without, eMRI-defined TV progression reaching 38% vs. 19%, respectively, by 5 years.
Eradicating intraprostatic hormone refractory prostate cancer (HRPC) by maximizing local control and randomized trials assessing whether survival is improved when agents active against HRPC are combined with maximal local therapy are needed in men who progress based on eMRI during nAST.
Prostate cancer; Magnetic resonance imaging; Radiation therapy; Androgen suppression therapy