Validation of metastasis-free survival as a surrogate endpoint for overall survival in localized prostate cancer in the era of docetaxel for castration-resistant prostate cancer

BACKGROUND

Prior work from the Intermediate Clinical Endpoints in Cancer of the Prostate (ICECaP) consortium (ICECaP-1) demonstrated that metastasis-free survival (MFS) is a valid surrogate for overall survival (OS) in localized prostate cancer (PCa). This was based on data from patients treated predominantly before 2004, prior to docetaxel being available for the treatment of metastatic castrate-resistant prostate cancer (mCRPC). We sought to validate surrogacy in a more contemporary era (ICECaP-2) with greater availability of docetaxel and other systemic therapies for mCRPC.

PATIENTS AND METHODS

Eligible trials for ICECaP-2 were those providing individual patient data (IPD) after publication of ICECaP-1 and evaluating adjuvant/salvage therapy for localized PCa, and which collected MFS and OS data. MFS was defined as distant metastases or death from any cause, and OS was defined as death from any cause. Surrogacy was evaluated using a meta-analytic two-stage validation model, with an R2 ≥ 0.7 defined a priori as clinically relevant.

RESULTS

A total of 15 164 IPD from 14 trials were included in ICECaP-2, with 70% of patients treated after 2004. The median follow-up was 8.3 years and the median postmetastasis survival was 3.1 years in ICECaP-2, compared with 1.9 years in ICECaP-1. For surrogacy condition 1, Kendall's tau was 0.92 for MFS with OS at the patient level, and R2 from weighted linear regression (WLR) of 8-year OS on 5-year MFS was 0.73 (95% confidence interval 0.53-0.82) at the trial level. For condition 2, R2 was 0.83 (95% confidence interval 0.64-0.89) from WLR of log[hazard ratio (HR)]-OS on log(HR)-MFS. The surrogate threshold effect on OS was an HR(MFS) of 0.81.

CONCLUSIONS

MFS remained a valid surrogate for OS in a more contemporary era, where patients had greater access to docetaxel and other systemic therapies for mCRPC. This supports the use of MFS as the primary outcome measure for ongoing adjuvant trials in localized PCa.

Positive Emotional Experience: Induced by Vibroacoustic Stimulation Using a Body Monochord in Patients with Psychosomatic Disorders: Is Associated with an Increase in EEG-Theta and a Decrease in EEG-Alpha Power

Relaxation and meditation techniques are generally characterized by focusing attention, which is associated with an increase of frontal EEG Theta. Some studies on music perception suggest an activation of Frontal Midline Theta during emotionally positive attribution, others display a lateralization of electrocortical processes in the attribution of music induced emotion of different valence. The present study examined the effects of vibroacoustic stimulation using a Body Monochord and the conventional relaxation music from an audio CD on the spontaneous EEG of patients suffering from psychosomatic disorders (N = 60). Each treatment took about 20 min and was presented to the patients in random order. Subjective experience was recorded via self-rating scale. EEG power spectra of the Theta, Alpha-1 and Alpha-2 bands were analysed and compard between the two treatment conditions. There was no lateralization of electrocortical activity in terms of the emotional experience of the musical pieces. A reduction in Alpha-2 power occurred during both treatments. An emotionally positive attribution of the experience of the vibroacoustically induced relaxation state is characterized by a more pronounced release of control. In the context of focused attention this is interpreted as flow experience. The spontaneous EEG showed an increase in Theta power, particularly in the frontal medial and central medial area, and a greater reduction in Alpha-2 power. The intensity of positive emotional feelings during the CD music showed no significant effect on the increase in Theta power.

Impact of sildenafil on marital and sexual adjustment in patients and their wives after radiotherapy and short-term androgen suppression for prostate cancer: analysis of RTOG 0215

PURPOSE

The Radiation Therapy Oncology Group (RTOG) 0215 investigated the efficacy of sildenafil in improving erectile dysfunction following radiotherapy and neoadjuvant/concurrent androgen deprivation therapy among prostate cancer patients and found a significant improvement on drug but only in 21% of study participants. This paper reports on a secondary aim to investigate the effect of sildenafil on overall sexual and marital adjustment among both patients and their wives.

METHODS

RTOG 0215 was a placebo-controlled, double-blind, crossover trial of sildenafil. Participation of wives was optional. Twenty-four married heterosexual couples (33% of heterosexual couples in study) completed the Sexual Adjustment Questionnaire and Locke's Marital Adjustment Test. Treatment differences in mean change scores were evaluated by paired t-tests, and the proportion of patients achieving a clinically meaningful change was evaluated using chi-square tests. Spearman's correlation coefficients were used to determine the association of adjustment between patients and wives.

RESULTS

There was no significant change in either sexual or marital adjustment for patients. For wives, there was a trend for improvement in sexual adjustment but no significant change in marital adjustment. Change in marital adjustment between patients and wives was weakly related (r(s) = 0.15, p = 0.48), and for sexual adjustment, there was a moderate, but nonsignificant relationship (r(s) = 0.40, p = 0.09).

CONCLUSIONS

Larger studies are warranted to further examine possible differences in sexual experiences and treatment needs between prostate cancer patients and their wives, as well as to assess predictors of sildenafil response.

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

5123

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.

The impact of the duration of adjuvant hormonal therapy in patients with unfavorable prognosis prostate cancer treated with radiotherapy: Secondary analysis of RTOG 85–31

5062

Background: RTOG 85–31 was a Phase III trial of androgen suppression for life as an adjuvant to radiotherapy. However not all patients continued on the protocol-mandated long-term hormonal therapy despite no evidence of recurrent disease. This analysis correlates duration of adjuvant hormonal therapy and outcomes among patients who prematurely discontinued long-term hormonal therapy. Methods: The protocol mandated pelvic radiotherapy (60–66 Gy) followed by goserelin 3.6 mg monthly given indefinitely or until disease progression. To avoid potential bias due to early progression/death, only patients who were alive with no evidence of disease at the time of cessation of hormonal therapy were included. There were 377 analyzable patients. Patients were divided in groups based on the hormonal therapy duration (HTD), as follows: = 1 year (27.3%), 1< and =2 years (11.4%), 2< and =4 years (13.3%), 4< and =6 years (10.6%) and > 6 years (37.4%). End-points were overall survival, disease-free survival, disease-free survival with PSA <1.5 ng/mL, disease-specific survival, local failure and distant failure. Cox-proportional hazards regression model was used to test the outcomes among the 5 groups. Results: The median follow-up time of surviving patients is 11.27 years. Pretreatment characteristics by hormone duration groups were well balanced except for age. The median duration of adjuvant hormonal therapy was 3.59 years. For each outcome, there are statistically significant differences among the 5 HTD groups in all outcomes without adjusting for other covariates. Pairwise comparisons show that HTD > 6 year group is significantly associated with having an improved survival and fewer failure events than all other HTD groups (HR < 1, p-value <0.0001). Adjusted for age and stratification variables, the HTD>6 year group remains the only group significantly associated with having fewer failure events in all outcomes. Conclusions: Prolonged HTD of > 6 years is significantly associated with improvements in all end-points studied. Based on these data, decreasing HTD to < 6 years may have a detrimental effect in patients with unfavorable prostate cancer.

No significant financial relationships to disclose.

Providing practitioner-specific outcomes is associated with higher patient satisfaction with information about prostate cancer treatment

6106

Background: After being diagnosed with prostate cancer, patients must assimilate abundant cancer related information. Satisfaction with Information (SWI) is a patient’s cognitive evaluation of information sources used to understand and select therapy. We sought to describe sources of information used by prostate cancer patients and to identify factors associated with SWI. Methods: 1,072 men with newly diagnosed prostate cancer have enrolled in the prospective, multi-center PRostate cancer Outcomes and Satisfaction with Treatment Quality Assessment (PROST-QA) study. Reports of source(s) of information were documented prior to treatment (radical prostatectomy, external radiation, brachytherapy or combination). The validated SWI domain of the Service Satisfaction Scale-Cancer (SSS-Ca) was completed by patients 2 months following treatment. Relationships between socio-economic factors, demographics, cancer severity, and types of information sources and satisfaction (SWI) were evaluated with multivariate regression. Results: Sources of information endorsed by patients varied by race ( Table ), education, and study site. The most helpful sources of information were description of treatment by a physician (32.8%), books and internet (18.3% each), family/friends (16.6%) and pamphlets/brochures (11.4%). In bivariate analysis internet use was negatively associated with SWI (p=0.025). In multivariable models patient age (p=0.005) and information provided by the physician regarding their own outcomes (p=0.01) were independently associated with SWI. Conclusions: Although a variety of informational sources were endorsed by patients, only printed results for physician’s own patients was associated with SWI. Because SWI is a function of both experiences and expectations, providing patients with a treating physician’s results may improve satisfaction by enhancing concordance of expectations and outcomes.

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