Association of a Simulated Institutional Gender Equity Initiative With Gender-Based Disparities in Medical School Faculty Salaries and Promotions

IMPORTANCE

Despite progress in narrowing gender-based salary gaps, notable disparities persist in the scientific community. The significance of pay difference may be underestimated, with little data evaluating its effect on lifetime wealth after accounting for factors like time to promotion and savings.

OBJECTIVES

To characterize gender disparities in salary and assess the outcomes associated with a gender equity initiative (GEI).

DESIGN, SETTING, AND PARTICIPANTS

Quality improvement study with simulations of salary and additional accumulated wealth (AAW) using retrospectively reviewed Johns Hopkins University School of Medicine annual salary and promotion data. All academic faculty were included in the faculty salary analysis from 2005 (n = 1481) and 2016 (n = 1885).

MAIN OUTCOMES AND MEASURES

Salary and longitudinal promotion data from 2005 to 2016 were used to estimate gender-based differences in salary and time to promotion. The effect of these differences on total salary and AAW, including retirement and salary-based investments, was simulated for a representative male and female faculty member over a 30-year career in 3 scenarios: (1) pre-GEI, (2) post-GEI, and (3) in real time for GEI, beginning with and progressing through these initiatives.

RESULTS

Analyses of salaries of 1481 faculty (432 women) in 2005 and 1885 faculty (742 women) in 2016 revealed that a decade after GEI implementation, the overall mean (SE) salary gap by gender decreased from -2.6% (1.2%) (95% CI, -5.6% to -0.3%) to -1.9% (1.1%) (95% CI, -4.1% to 0.3%). Simulation of pre-GEI disparities correlated with male faculty collecting an average lifetime AAW of $501 416 more than the equivalent woman, with disparities persisting past retirement. The AAW gap decreased to $210 829 in the real-time GEI simulation and to $66 104 using post-GEI conditions, reflecting success of GEI efforts.

CONCLUSIONS AND RELEVANCE

Even small gender-based salary gaps are associated with substantial differences in lifetime wealth, but an institutional commitment to achieving equitable promotion and compensation for women can appreciably reduce these disparities. The findings of this study support broad implementation of similar initiatives without delay, as results may take more than a decade to emerge. A modifiable version of the simulation is provided so that external users may assess the potential disparities present within their own institutions.

Efficacy of Radium-223 in Bone-metastatic Castration-resistant Prostate Cancer with and Without Homologous Repair Gene Defects

BACKGROUND

Pathogenic mutations in genes mediating homologous recombination (HR) DNA repair are present in 20-30% of men with metastatic castrate-resistant prostate cancer (mCRPC). Radium-223 is a bone-seeking α-emitter that induces double-strand DNA breaks, thereby killing cancer cells in the bone microenvironment.

OBJECTIVE

To evaluate the potential impact of germline or somatic HR-deficiency (HRD) mutations on radium-223 efficacy in mCRPC with bone metastasis.

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective single-institution study. Medical records of 190 mCRPC patients for whom germline and/or somatic DNA sequencing data were available were reviewed. Of these patients, 28 had received standard-of-care radium-223 at Johns Hopkins between February 2013 and February 2018.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Alkaline phosphatase (ALP) responses and time-to-ALP-progression were the coprimary endpoints. Prostate-specific antigen (PSA) responses, overall survival (OS), and time to next systemic therapy were also evaluated.

RESULTS AND LIMITATIONS

Of the 28 patients included, 10 men (35.7%) had a germline/somatic HRD mutation (three in BRCA2, and one each in ATM, ATR, CHEK2, FANCG, FANCI, FANCL, and PALB2) and 18 (64.3%) did not. Men with HRD mutations (HRD+) had numerically lower ages (66 vs 73yr, p=0.25), more soft-tissue metastases (50% vs 38%, p=0.43), and higher baseline ALP levels (130 vs 108 U/l, p=0.84). Compared with HRD(-) men, HRD(+) patients showed greater ALP responses (80% vs 39%, p=0.04), longer time to ALP progression (median10.4 vs 5.8mo, hazard ratio [HR] 6.4, p=0.005), and a trend toward longer OS (median 36.9 vs 19.0mo, HR 3.3, p=0.11). PSA responses (0% vs 0%, p>0.99) and time to next systemic therapy (HR 1.5, p=0.39) were similar between the two groups. Results are limited by the retrospective nature of the analysis and the small sample size.

CONCLUSIONS

In this exploratory study, bone-metastatic CRPC patients with inactivating HRD mutations demonstrated significantly improved ALP responses and time to ALP progression. These results should motivate prospective validation of the "synthetic lethality" hypothesis between HRD mutations and radium-223 activity.

PATIENT SUMMARY

In this report, we retrospectively examined outcomes to metastatic prostate cancer in patients with and without DNA repair mutations who received radium-223, a therapy that kills cancer cells by causing direct DNA damage. Our study suggested that patients who have inherited or acquired DNA repair gene mutations derived greater benefit from radium-223 when compared with patients without these mutations. We concluded that radium-223 might have an important role in this setting; however, prospective studies are needed to confirm whether DNA repair mutations truly make radium-223 work better or not.

Phase II study of intraoperative dosimetry for prostate brachytherapy using registered ultrasound and fluoroscopy

PURPOSE

To assess the performance of a system of intraoperative dosimetry and obtain estimates of dosimetry outcomes achieved when utilizing the system in a Phase II clinical trial.

METHODS AND MATERIALS

Forty-five patients undergoing permanent Pd-103 seed implantation for prostate cancer were prospectively enrolled. Seed implantation was performed and dose was tracked intraoperatively using intraoperative registered ultrasound and fluoroscopy (iRUF). Three-dimensional seed locations were computed from X-rays and registered to ultrasound for intraoperative dosimetry, followed by adaptive plan modification to achieve prostate V100 ≥95% and ≥95% D90. Time required for iRUF was recorded. Postoperative CT/MRI scans were performed 1 day after the implantation and used as reference for dosimetric analysis. Dosimetric parameters for the prostate and urethra were compared between standard ultrasound-based dosimetry (USD), iRUF, and postoperative CT/MRI.

RESULTS

Mean total time for iRUF was <30 min. A mean of four seeds (0-12) were added per implant to correct cold spots discovered by iRUF. Day 1 CT/MRI prostate V100 was ≥95% for 44/45 patients; 1 patient had Day 1 V100 93%. No patient had rectal V100 exceeding 1 cc. Compared to CT/MRI, iRUF dosimetry had significantly smaller mean differences and higher correlations for all prostate and urethral dosimetric parameters examined than USD. Both USD and iRUF tended to overestimate dose, but with less bias in iRUF than USD.

CONCLUSIONS

Intraoperative dosimetry utilizing iRUF was associated with acceptable increase in procedure time and enabled very high rates of achieving excellent prostate dose coverage. iRUF intraoperative dosimetry approximated postoperative CT/MRI dosimetry to a greater degree than USD for the prostate and urethra.

Elective Nodal Irradiation Attenuates the Combinatorial Efficacy of Stereotactic Radiation Therapy and Immunotherapy

Purpose: In the proper context, radiotherapy can promote antitumor immunity. It is unknown if elective nodal irradiation (ENI), a strategy that irradiates tumor-associated draining lymph nodes (DLN), affects adaptive immune responses and combinatorial efficacy of radiotherapy with immune checkpoint blockade (ICB).Experimental Design: We developed a preclinical model to compare stereotactic radiotherapy (Tumor RT) with or without ENI to examine immunologic differences between radiotherapy techniques that spare or irradiate the DLN.Results: Tumor RT was associated with upregulation of an intratumoral T-cell chemoattractant chemokine signature (CXCR3, CCR5-related) that resulted in robust infiltration of antigen-specific CD8⁺ effector T cells as well as FoxP3⁺ regulatory T cells (Tregs). The addition of ENI attenuated chemokine expression, restrained immune infiltration, and adversely affected survival when combined with ICB, especially with anti-CLTA4 therapy. The combination of stereotactic radiotherapy and ICB led to long-term survival in a subset of mice and was associated with favorable CD8 effector-to-Treg ratios and increased intratumoral density of antigen-specific CD8⁺ T cells. Although radiotherapy technique (Tumor RT vs. ENI) affected initial tumor control and survival, the ability to reject tumor upon rechallenge was partially dependent upon the mechanism of action of ICB; as radiotherapy/anti-CTLA4 was superior to radiotherapy/anti-PD-1.Conclusions: Our results highlight that irradiation of the DLN restrains adaptive immune responses through altered chemokine expression and CD8⁺ T-cell trafficking. These data have implications for combining radiotherapy and ICB, long-term survival, and induction of immunologic memory. Clinically, the immunomodulatory effect of the radiotherapy strategy should be considered when combining stereotactic radiotherapy with immunotherapy. Clin Cancer Res; 24(20); 5058-71. ©2018 AACR.

Detectable end of radiation prostate specific antigen assists in identifying men with unfavorable intermediate-risk prostate cancer at high risk of distant recurrence and cancer-specific mortality

BACKGROUND

Undetectable End of Radiation PSA (EOR-PSA) has been shown to predict improved survival in prostate cancer (PCa). While validating the unfavorable intermediate-risk (UIR) and favorable intermediate-risk (FIR) stratifications among Johns Hopkins PCa patients treated with radiotherapy, we examined whether EOR-PSA could further risk stratify UIR men for survival.

METHODS

A total of 302 IR patients were identified in the Johns Hopkins PCa database (178 UIR, 124 FIR). Kaplan-Meier curves and multivariable analysis was performed via Cox regression for biochemical recurrence free survival (bRFS), distant metastasis free survival (DMFS), and overall survival (OS), while a competing risks model was used for PCa specific survival (PCSS). Among the 235 patients with known EOR-PSA values, we then stratified by EOR-PSA and performed the aforementioned analysis.

RESULTS

The median follow-up time was 11.5 years (138 months). UIR was predictive of worse DMFS and PCSS (P = 0.008 and P = 0.023) on multivariable analysis (MVA). Increased radiation dose was significant for improved DMFS (P = 0.016) on MVA. EOR-PSA was excluded from the models because it did not trend towards significance as a continuous or binary variable due to interaction with UIR, and we were unable to converge a multivariable model with a variable to control for this interaction. However, when stratifying by detectable versus undetectable EOR-PSA, UIR had worse DMFS and PCSS among detectable EOR-PSA patients, but not undetectable patients. UIR was significant on MVA among detectable EOR-PSA patients for DMFS (P = 0.021) and PCSS (P = 0.033), while RT dose also predicted PCSS (P = 0.013).

CONCLUSIONS

EOR-PSA can assist in predicting DMFS and PCSS among UIR patients, suggesting a clinically meaningful time point for considering intensification of treatment in clinical trials of intermediate-risk men.

Radical Prostatectomy, External Beam Radiotherapy, or External Beam Radiotherapy With Brachytherapy Boost and Disease Progression and Mortality in Patients With Gleason Score 9-10 Prostate Cancer

IMPORTANCE

The optimal treatment for Gleason score 9-10 prostate cancer is unknown.

OBJECTIVE

To compare clinical outcomes of patients with Gleason score 9-10 prostate cancer after definitive treatment.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study in 12 tertiary centers (11 in the United States, 1 in Norway), with 1809 patients treated between 2000 and 2013.

EXPOSURES

Radical prostatectomy (RP), external beam radiotherapy (EBRT) with androgen deprivation therapy, or EBRT plus brachytherapy boost (EBRT+BT) with androgen deprivation therapy.

MAIN OUTCOMES AND MEASURES

The primary outcome was prostate cancer-specific mortality; distant metastasis-free survival and overall survival were secondary outcomes.

RESULTS

Of 1809 men, 639 underwent RP, 734 EBRT, and 436 EBRT+BT. Median ages were 61, 67.7, and 67.5 years; median follow-up was 4.2, 5.1, and 6.3 years, respectively. By 10 years, 91 RP, 186 EBRT, and 90 EBRT+BT patients had died. Adjusted 5-year prostate cancer-specific mortality rates were RP, 12% (95% CI, 8%-17%); EBRT, 13% (95% CI, 8%-19%); and EBRT+BT, 3% (95% CI, 1%-5%). EBRT+BT was associated with significantly lower prostate cancer-specific mortality than either RP or EBRT (cause-specific HRs of 0.38 [95% CI, 0.21-0.68] and 0.41 [95% CI, 0.24-0.71]). Adjusted 5-year incidence rates of distant metastasis were RP, 24% (95% CI, 19%-30%); EBRT, 24% (95% CI, 20%-28%); and EBRT+BT, 8% (95% CI, 5%-11%). EBRT+BT was associated with a significantly lower rate of distant metastasis (propensity-score-adjusted cause-specific HRs of 0.27 [95% CI, 0.17-0.43] for RP and 0.30 [95% CI, 0.19-0.47] for EBRT). Adjusted 7.5-year all-cause mortality rates were RP, 17% (95% CI, 11%-23%); EBRT, 18% (95% CI, 14%-24%); and EBRT+BT, 10% (95% CI, 7%-13%). Within the first 7.5 years of follow-up, EBRT+BT was associated with significantly lower all-cause mortality (cause-specific HRs of 0.66 [95% CI, 0.46-0.96] for RP and 0.61 [95% CI, 0.45-0.84] for EBRT). After the first 7.5 years, the corresponding HRs were 1.16 (95% CI, 0.70-1.92) and 0.87 (95% CI, 0.57-1.32). No significant differences in prostate cancer-specific mortality, distant metastasis, or all-cause mortality (≤7.5 and >7.5 years) were found between men treated with EBRT or RP (cause-specific HRs of 0.92 [95% CI, 0.67-1.26], 0.90 [95% CI, 0.70-1.14], 1.07 [95% CI, 0.80-1.44], and 1.34 [95% CI, 0.85-2.11]).

CONCLUSIONS AND RELEVANCE

Among patients with Gleason score 9-10 prostate cancer, treatment with EBRT+BT with androgen deprivation therapy was associated with significantly better prostate cancer-specific mortality and longer time to distant metastasis compared with EBRT with androgen deprivation therapy or with RP.

Use of 5-alpha-reductase inhibitors as alternatives to luteinizing-hormone releasing hormone (LHRH) analogs or anti-androgens for prostate downsizing before brachytherapy

INTRODUCTION

Prostate hypertrophy, median lobe hypertrophy, and pubic arch interference (PAI) are relative contraindications to brachytherapy because of potential morbidity and technical considerations. GnRH analogs or non-steroidal anti-androgens are currently utilized to achieve prostatic downsizing prior to brachytherapy. However, such agents have been associated with effects on body habitus, metabolism, and quality of life. In contrast, 5-alpha reductase inhibitors (5-ARI) are far less frequently associated with these morbidities.

METHODS AND MATERIALS

Patients with large gland size, median lobe hypertrophy, or PAI were offered 5-ARI therapy. Repeat transrectal ultrasound was performed at 3 or 4 months, followed by brachytherapy if resolution was achieved. If downsizing was inadequate, patients were offered continuation of 5-ARI for additional 3 months, gonadotropin-releasing hormone analog (GnRH) agonist or antiandrogen therapy, or other curative treatment.

RESULTS

Of 59 patients with follow-up available, 42 (71%) were deemed to have adequate downsizing; 37 (63%) after 3 to 4 months of 5-ARI and 5 (8%) after 7 to 8 months. Seventeen patients (29%) received other treatments because of inadequate effect. Median volume reduction was 20%. Of 41 patients undergoing brachytherapy, 4 (9.7%) required temporary catheterization because of obstruction. Median follow-up after implantation was 25 months (range, 1-64). Median time for return to International Prostate Symptom Score ≤5 of baseline score was 7 months (interquartile ratio, 6-13). All but 1 patient who received brachytherapy remain biochemically controlled.

CONCLUSION

5-ARI monotherapy is an alternative for downsizing in patients with hypertrophy or PAI, with more than 70% achieving adequate downsizing without use of GnRH analogs or antiandrogens. Patients who received brachytherapy experienced typical rates of postimplant urinary morbidity.

Effects of biodegradable hydrogel spacer injection on contralateral submandibular gland sparing in radiotherapy for head and neck cancers

Xerostomia is the most common late toxicity after head and neck radiation. We demonstrate injection of a hydrogel spacer anteriorly displacing the submandibular gland. This procedure enables reduced dose to the displaced submandibular gland in cadaveric models of oropharynx cancer treated with IMRT, with potential implications in reducing xerostomia risk.

A Novel Absorbable Radiopaque Hydrogel Spacer to Separate the Head of the Pancreas and Duodenum in Radiation Therapy for Pancreatic Cancer

PURPOSE

We assessed the feasibility and theoretical dosimetric advantages of an injectable hydrogel to increase the space between the head of the pancreas (HOP) and duodenum in a human cadaveric model.

METHODS AND MATERIALS

Using 3 human cadaveric specimens, an absorbable radiopaque hydrogel was injected between the HOP and duodenum by way of open laparotomy in 1 case and endoscopic ultrasound (EUS) guidance in 2 cases. The cadavers were subsequently imaged using computed tomography and dissected for histologic confirmation of hydrogel placement. The duodenal dose reduction and planning target volume (PTV) coverage were characterized using pre- and postspacer injection stereotactic body radiation therapy (SBRT) plans for the 2 cadavers with EUS-guided placement, the delivery method that appeared the most clinically desirable. Modeling studies were performed using 60 SBRT plans consisting of 10 previously treated patients with unresectable pancreatic cancer, each with 6 different HOP-duodenum separation distances. The duodenal volume receiving 15 Gy (V15), 20 Gy (V20), and 33 Gy (V33) was assessed for each iteration.

RESULTS

In the 3 cadaveric studies, an average of 0.9 cm, 1.1 cm, and 0.9 cm HOP-duodenum separation was achieved. In the 2 EUS cases, the V20 decreased from 3.86 cm³ to 0.36 cm³ and 3.75 cm³ to 1.08 cm³ (treatment constraint <3 cm³), and the V15 decreased from 7.07 cm³ to 2.02 cm³ and 9.12 cm³ to 3.91 cm³ (treatment constraint <9 cm³). The PTV coverage improved or was comparable between the pre- and postinjection studies. Modeling studies demonstrated that a separation of 8 mm was sufficient to consistently reduce the V15, V20, and V33 to acceptable clinical constraints.

CONCLUSIONS

Currently, dose escalation has been limited owing to radiosensitive structures adjacent to the pancreas. We demonstrated the feasibility of hydrogel separation of the HOP and duodenum. Future studies will evaluate the safety and efficacy of this technique with the potential for more effective dose escalation using SBRT or intensity-modulated radiation therapy to improve the outcomes in patients with unresectable pancreatic cancer.

A phase II randomized trial of Observation versus stereotactic ablative RadiatIon for OLigometastatic prostate CancEr (ORIOLE)

Background

We describe a randomized, non-blinded Phase II interventional study to assess the safety and efficacy of stereotactic ablative radiotherapy (SABR) for hormone-sensitive oligometastatic prostate adenocarcinoma, and to describe the biology of the oligometastatic state using immunologic, cellular, molecular, and functional imaging correlates. 54 men with oligometastatic prostate adenocarcinoma will be accrued. The primary clinical endpoint will be progression at 6 months from randomization with the hypothesis that SABR to all metastases will forestall progression by disrupting the metastatic process. Secondary clinical endpoints will include local control at 6 months post-SABR, toxicity and quality of life, and androgen deprivation therapy (ADT)-free survival (ADT-FS). Further fundamental analysis of the oligometastatic state with be achieved through correlation with investigational ¹⁸F–DCFPyL PET/CT imaging and measurement of circulating tumor cells, circulating tumor DNA, and circulating T-cell receptor repertoires, facilitating an unprecedented opportunity to characterize, in isolation, the effects of SABR on the dynamics of and immunologic response to oligometastatic disease.

Methods/design

Patients will be randomized 2:1 to SABR or observation with minimization to balance assignment by primary intervention, prior hormonal therapy, and PSA doubling time. Progression after 6 months will be compared using Fisher’s exact test. Hazard ratios and Kaplan-Meier estimates of progression free survival (PFS), ADT free survival (ADT-FS), time to locoregional progression (TTLP) and time to distant progression (TTDP) will be calculated based on an intention-to-treat. Local control will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Withdrawal from the study prior to 6 months will be counted as progression. Adverse events will be summarized by type and grade. Quality of life pre- and post- SABR will be measured by Brief Pain Inventory.

Discussion

The ORIOLE trial is the first randomized, non-blinded Phase II interventional study in the North America evaluating the safety and efficacy of SABR in oligometastatic hormone-sensitive prostate cancer. Leading-edge laboratory and imaging correlates will provide unique insight into the effects of SABR on the oligometastatic state.

Trial registrations

ClinicalTrials.gov Identifier: NCT02680587.

URL of Registry: https://clinicaltrials.gov/show/NCT02680587

Date of Registration: 02/08/2016.

Date of First Participant Enrollment: 05/23/2016.

Unscreened older men diagnosed with prostate cancer are at increased risk of aggressive disease

BACKGROUND

To evaluate the relationship between PSA testing history and high-risk disease among older men diagnosed with prostate cancer.

METHODS

Records from 1993 to 2014 were reviewed for men who underwent radiotherapy for prostate cancer at age 75 years or older. Patients were classified into one of four groups based on PSA-testing history: (1) no PSA testing; (2) incomplete/ineffective PSA testing; (3) PSA testing; or (4) cannot be determined. Outcomes of interest were National Comprehensive Cancer Network (NCCN) risk group (that is, low, intermediate or high risk) and biopsy grade at diagnosis. Multivariable logistic regression was used to determine the association between PSA testing history and high-risk cancer.

RESULTS

PSA-testing history was available in 274 (94.5%) of 290 subjects meeting study criteria. In total, 148 men (54.0%) underwent PSA testing with follow-up biopsy, 72 (26.3%) underwent PSA testing without appropriate follow-up, and 54 men (19.7%) did not undergo PSA testing. Patients who underwent PSA testing were significantly less likely to be diagnosed with NCCN high-risk cancer (23.0% vs 51.6%, P<0.001). On multivariable analysis, men with no/incomplete PSA testing had more than three-fold increased odds of high-risk disease at diagnosis (odds ratio 3.39, 95% confidence interval 1.96-5.87, P<0.001) as compared to the tested population.

CONCLUSIONS

Older men who underwent no PSA testing or incomplete testing were significantly more likely to be diagnosed with high-risk prostate cancer than those who were previously screened. It is reasonable to consider screening in healthy older men likely to benefit from early detection and treatment.

Stereotactic ablative radiation therapy for the treatment of oligometastatic prostate cancer

5020

Background: The importance of local treatment in oligometastatic prostate cancer (OPC) is unknown. Stereotactic ablative radiotherapy (SABR) is highly focused, high-dose radiation that is well suited for treatment of oligometastases. Here we report on the safety and preliminary clinical outcomes of SABR in a modern cohort of OPC men. Methods: Eighty four men who satisfied criteria of OPC diagnosed on imaging underwent consolidative SABR were then followed prospectively on our IRB approved registry by our GU multidisciplinary team. We collected demographic, clinical, toxicity and efficacy information. We examined the first 66 men in this preliminary report to allow for a minimum of 4.5 months follow-up. SABR was delivered in 1-5 fractions of 5-18 Gy. Kaplan-Meier method was used to assess local progression-free survival (LPFS), biochemical progression-free survival (bPFS; PSA nadir+2), distant progression free survival (DPFS), ADT-free survival (ADT-FS) and time-to-next intervention (TTNI). Results: Of the 66 OPC patients analyzed, 25 (38%) men presented as synchronous OPC and the remaining 41 had recurrent OPC. Median and mean follow-up was 61 and 66 weeks, respectively. Patient and disease factors as listed in the Table. Crude Grade 1 and 2 acute toxicities were 36% and 11%, respectively, with no Grade > 2 toxicity. SABR was delivered to 134 metastases: 89 bone (66%), 40 nodal (30%) and 5 (4%) visceral metastases. Overall LPFS at 1-year was 92%. The bPFS and DPFS at 1-year were 69% and 69%, respectively. Median TTNI was not reached yet. Of the 18 men with hormone sensitive prostate cancer who had their ADT deferred, 11/18 (56%) remain free of disease following SABR (1-year ADT-FS was 78%) and in 17 castration resistant men, 11 had > 50% PSA declines with 1-year TTNI of 30% with a median of 45 weeks. Conclusions: Consolidative SABRfor OPCis feasible and well tolerated. The preliminary clinical outcomes in our series is limited by heterogeneity and size but our data suggests that this approach is worthy of further prospective study. [Table: see text]

A phase II randomized trial of observation versus stereotactic ablative radiation for oligometastatic prostate cancer (ORIOLE)

TPS5094

Background: ORIOLE is a randomized, non-blinded Phase II interventional study evaluating the safety and efficacy of SBRT in biochemically recurrent, oligometastatic, hormone-sensitive prostate cancer at 3 centers in the US. Patients will be stratified by clinical characteristics and randomized 2:1 to SBRT or observation. The primary clinical endpoint is progression at 6 months defined by PSA increase, radiologic or clinical evidence, ADT initiation, or death from any cause. Secondary endpoints include local control at 6 months, SBRT-associated toxicity and quality of life, and ADT-free survival. Imaging and laboratory correlates will characterize, in isolation, the effects of SBRT on oligometastatic disease. Methods: Eligible patients are hormone-sensitive, have undergone prior definitive treatment and recurred with 1-3 asymptomatic bone or soft tissue metastases diagnosed within 6 months, PSA doubling time (PSADT) < 15 months, ECOG performance status ≤ 2, and normal organ and marrow function. Minimization will be used to balance assignment by primary intervention, prior ADT, and PSADT. Accrual of 54 patients provides 85% power to detect a decrease in progression rate from 80% to 40% with type I error = 0.05 using one-sided Fisher’s exact test. Hazard ratios and Kaplan-Meier estimates of progression free survival, ADT free survival, and time to locoregional and distant progression will be calculated based on intention-to-treat. Local control will be assessed using RECIST 1.1 criteria. Withdrawal prior to 6 months will be counted as progression. Adverse events will be summarized and quality of life pre- and post-SBRT will be measured by Brief Pain Inventory. The investigational targeted imaging agent 18F-DCFPyL will be compared to bone scan and CT for identifying oligometastases before SBRT and monitoring disease response following SBRT. Biological alterations induced by SBRT will be investigated using circulating tumor cell analysis, deep sequencing of circulating tumor DNA, and T-cell repertoire profiling. A hereditary cancer assay will inform efforts to advance personalized screening and therapy. Clinical trial information: NCT02680587.

TWIST1-WDR5-Hottip Regulates Hoxa9 Chromatin to Facilitate Prostate Cancer Metastasis

TWIST1 is a transcription factor critical for development that can promote prostate cancer metastasis. During embryonic development, TWIST1 and HOXA9 are coexpressed in mouse prostate and then silenced postnatally. Here we report that TWIST1 and HOXA9 coexpression are reactivated in mouse and human primary prostate tumors and are further enriched in human metastases, correlating with survival. TWIST1 formed a complex with WDR5 and the lncRNA Hottip/HOTTIP, members of the MLL/COMPASS-like H3K4 methylases, which regulate chromatin in the Hox/HOX cluster during development. TWIST1 overexpression led to coenrichment of TWIST1 and WDR5 as well as increased H3K4me3 chromatin at the Hoxa9/HOXA9 promoter, which was dependent on WDR5. Expression of WDR5 and Hottip/HOTTIP was also required for TWIST1-induced upregulation of HOXA9 and aggressive cellular phenotypes such as invasion and migration. Pharmacologic inhibition of HOXA9 prevented TWIST1-induced aggressive prostate cancer cellular phenotypes in vitro and metastasis in vivo This study demonstrates a novel mechanism by which TWIST1 regulates chromatin and gene expression by cooperating with the COMPASS-like complex to increase H3K4 trimethylation at target gene promoters. Our findings highlight a TWIST1-HOXA9 embryonic prostate developmental program that is reactivated during prostate cancer metastasis and is therapeutically targetable. Cancer Res; 77(12); 3181-93. ©2017 AACR.

Abstract PR03: Prophylactic nodal irradiation abrogates the synergy of tumor radiotherapy and immune checkpoint blockade

Background: Prophylactic nodal irradiation (PNI) is a strategy used to treat early stage cancers with the potential to enhance local control and prevent metastatic spread. It remains unclear whether irradiation of tumor-associated draining lymph nodes (LN) influences anti-tumor T cell responses. Our aim was to investigate the in vivo effects of nodal irradiation on the phenotype and function of tumor infiltrating lymphocytes (TIL) and the impact of PNI on the anti-tumor effects of immunotherapy.

Methods: The Small Animal Radiation Research Platform (SARRP) delivered imaged-guided stereotactic radiation (RT) to tumor (T-only) or tumor and LN (T+LN). Syngeneic tumors (MC38 colon, B16 melanoma) were implanted in C57BL/6 mice and irradiated (12Gy x1) and/or treated with immune checkpoint blockade with αCTLA-4 IgG2a (depleting) or αPD-1 IgG1. The composition of the tumor microenvironment (TME) was assayed by flow cytometry. To query tumor-antigen specific T cell responses, adoptive transfer experiments were performed using OVA-specific CD8+ T-cells from Rag-/- OT-1 mice and OVA-MHC class I tetramer (SIINFEKL). Tumor lysate was also collected for chemokine analysis, and tumor outgrowth was quantified over time.

Results: T-only RT resulted in a significant increase (P&lt;0.01) in the proportion and absolute number of tumor infiltrating CD8+ effector T cells in comparison with T+LN RT. Immunosuppressive subsets (CD11b+ Gr-1hi MDSCs and FoxP3+ CD4+ Tregs) were also significantly increased in the T-only group. Ultimately, T-only RT significantly enhanced the CD8 effector:Treg ratio relative to untreated and T+LN treated tumors. Using the OVA-MHC class I tetramer to identify tumor-antigen specific CD8 T-cells, we observed that T-only RT significantly increased (P&lt;0.05) the number of tumor-specific CD8-T cells in the TME compared with T+LN RT. Interestingly, T-only RT resulted in a a significant expansion of non-OVA specific CD8 T cells which was not observed with T+LN RT, suggesting a polyclonal anti-tumor immune response. Functionally, a significant increase (P&lt;0.01) in the absolute number of IFNγ+ and TNFα+ antigen-specific TIL were noted with T-only RT. Mechanistically, a distinct chemokine signature correlated with robust TME immune infiltration and significantly elevated levels of CCL3/4/5 and CXCL10 (P&lt;0.05) were observed in tumor lysate collected from T-only RT tumors relative to T+LN RT samples. In an effort to understand the implications of the RT target on potential synergy with immune checkpoint blockade we performed survival experiments with T-only and T+LN RT in combination with αPD-1 or αCTLA-4. T-only RT in combination with αCTLA-4 yielded the best outcome with a 86% long-term survival (day 90 post-RT) compared with 30-36% long-term survival in mice treated with other combinations of RT + immune checkpoint blockade. Intriguingly, favorable CD8 effector:Treg ratio was able to predict treatment response and was dramatically higher (P&lt;0.001) among mice treated with T-only RT in combination with αCTLA-4.

Conclusions: We have successfully developed a SARRP-based early stage cancer model with the ability to target or spare the tumor-associated LN. Results to date demonstrate significant immunological differences that are contingent upon inclusion/exclusion of the LN. Long-term survival experiments suggest response and survival advantages with T-only RT, particularly in combination with αCTLA-4 blockade. Taken together, these data suggest that PNI may dampen anti-tumor immune responses and that Tumor-only RT might be a better strategy in combination immunotherapy regimens, although these results should be explored in carefully designed clinical trials.

This abstract is also being presented as Poster B41.

Citation Format: Ariel E. Marciscano, Ali Ghasemzadeh, Thomas R. Nirschl, Brian J. Francica, Debebe Theodros, Esteban Velarde, J Wong, Daniel LJ Thorek, Theodore L. DeWeese, Charles G. Drake. Prophylactic nodal irradiation abrogates the synergy of tumor radiotherapy and immune checkpoint blockade. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr PR03.

Evaluation of sexual function on a randomized trial of a prostate rectal spacer

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Background: The SpaceOAR phase 3 trial showed that a hydrogel spacer between the prostate and rectum decreased rectal dose and toxicity while improving bowel quality of life (QOL) after image guided prostate IMRT to 79.2 Gy. Here we evaluated dose to penile bulb as well as sexual function on this trial Methods: Sexual QOL was measured with the Expanded Prostate Cancer Index Composite (EPIC) by mean summary scores and the proportion of patients with a minimally important decline (MID) (11 points). Stratification was based on severe erectile dysfunction (ED)(EPIC < = 60) vs not. The single question on “Erections sufficient for intercourse over the preceding 4 weeks” was also evaluated. Results: Median Follow-up was 37 months with 63% of men evaluable at 3 years. With spacer the dose to the penile bulb was reduced for mean (21 vs 11 Gy), Dmax (46 vs 36 Gy), and V10-V30 (all p < 0.05). Baseline sexual function was 53 (±24) with 54% having severe ED with no difference between arms (p > 0.1). At 3 years average EPIC score was 39.7 (± 23) and 82% had severe ED with no differences between arms (p > 0.1). At enrollment 42% had EPIC > 60 with average summary of 77 (±8.3) which at 3 years was 53 (±24.8). In this sub-group at 3 years a higher EPIC was observed on the Spacer arm (57.7 (±24.1) vs. 44.6 (± 24.4)) which met the threshold for an MID without statistical significance (p = 0.07). Based on MID and twice that there was a trend favoring Spacer with 53% vs 75% for 11-point decline (p = 0.064) and 41% vs 60% for 22 point decline (p = 0.11). A small number of these men were potent at baseline and evaluable both at baseline and 3 years (n = 49). Of these 37.5% in the Control arm had erections sufficient for intercourse at 3 years as compared to 66.7% (p = 0.07) in the Spacer arm. Power analysis revealed 35% power to detect a change of 11 points between arms and 27% power to detect a difference of 22 points. Conclusions: The use of a hydrogel spacer decreased dose to the penile bulb with a suggestion of a clinically significant improvement in patient reported sexual function and potency. These did not achieve statistical significance potentially due to the high prevalence of ED at baseline and, therefore, the small evaluable sample size. Analysis of penile bulb dose and QOL is ongoing. Clinical trial information: NCT01538628.

End-of-radiation PSA as a novel prognostic factor in patients undergoing definitive radiation and androgen deprivation therapy for prostate cancer

Background

In men undergoing definitive radiation for prostate cancer, it is unclear whether early biochemical response can provide additional prognostic value beyond pre-treatment risk stratification.

Methods

Prostate cancer patients consecutively treated with definitive radiation at our institution by a single provider from 1993–2006 and who had an EOR PSA (n=688, median follow-up 11.2 years). We analyzed the association of an end-of-radiation (EOR) prostate-specific antigen (PSA) level, obtained during the last week of radiation, with survival outcomes. Multivariable-adjusted cox proportional hazards models were constructed to assess associations between a detectable EOR PSA (defined as ≥0.1 ng ml⁻¹) and biochemical failure-free survival (BFFS), metastasis-free survival (MFS), prostate cancer-specific survival (PCSS), and overall survival (OS). Kaplan-Meier survival curves were constructed, with stratification by EOR PSA.

Results

At the end of radiation, the PSA level was undetectable in 30% of patients. Men with a detectable EOR PSA experienced inferior 10-year BFFS (49.7% vs. 64.4%, p<0.001), 10-year MFS (84.8% vs. 92.0%, p=0.003), 10-year PCSS (94.3% vs. 98.2%, p=0.007), and 10-year OS (75.8% vs. 82.5%, p=0.01), as compared to men with an undetectable EOR PSA. Among NCCN intermediate- and high-risk men who were treated with definitive radiation and androgen deprivation therapy (ADT), a detectable EOR PSA was more strongly associated with PCSS than initial NCCN risk level (EOR PSA: HR 5.89, 95% CI 2.37–14.65, p<0.001; NCCN risk level: HR 2.01, 95% CI 0.74–5.42, p=0.168). Main study limitations are retrospective study design and associated biases.

Conclusions

EOR PSA was significantly associated with survival endpoints in men who received treated with definitive radiation and ADT. Whether the EOR PSA can be used to modulate treatment intensity merits further investigation.

Very High-Risk Localized Prostate Cancer: Outcomes Following Definitive Radiation

PURPOSE

Existing definitions of high-risk prostate cancer consist of men who experience significant heterogeneity in outcomes. As such, criteria that identify a subpopulation of National Comprehensive Cancer Network (NCCN) high-risk prostate cancer patients who are at very high risk (VHR) for poor survival outcomes following prostatectomy were recently developed at our institution and include the presence of any of the following disease characteristics: multiple NCCN high-risk factors, primary Gleason pattern 5 disease and/or ≥5 biopsy cores with Gleason sums of 8 to 10. Whether these criteria also apply to men undergoing definitive radiation is unclear, as is the optimal treatment regimen in these patients.

METHODS AND MATERIALS

All men consecutively treated with definitive radiation by a single provider from 1993 to 2006 and who fulfilled criteria for NCCN high-risk disease were identified (n=288), including 99 patients (34%) with VHR disease. Multivariate-adjusted competing risk regression models were constructed to assess associations between the VHR definition and biochemical failure (BF), distant metastasis (DM), and prostate cancer-specific mortality (PCSM). Multivariate-adjusted Cox regression analysis assessed the association of the VHR definition with overall mortality (OM). Cumulative incidences of failure endpoints were compared between VHR men and other NCCN high-risk men.

RESULTS

Men with VHR disease compared to other NCCN high-risk men experienced a higher 10-year incidence of BF (54.0% vs 35.4%, respectively, P<.001), DM (34.9% vs 13.4%, respectively, P<.001), PCSM (18.5% vs 5.9%, respectively, P<.001), and OM (36.4% vs 27.0%, respectively, P=.04). VHR men with a detectable prostate-specific antigen (PSA) concentration at the end of radiation (EOR) remained at high risk of 10-year PCSM compared to VHR men with an undetectable EOR PSA (31.0% vs 13.7%, respectively, P=.05).

CONCLUSIONS

NCCN high-risk prostate cancer patients who meet VHR criteria experience distinctly worse outcomes following definitive radiation and long-term androgen deprivation therapy, particularly if an EOR PSA is detectable. Optimal use of local therapies for VHR patients should be explored further, as should novel agents.

Androgen Deprivation Followed by Acute Androgen Stimulation Selectively Sensitizes AR-Positive Prostate Cancer Cells to Ionizing Radiation

PURPOSE

The current standard of care for patients with locally advanced prostate cancer is a combination of androgen deprivation and radiation therapy. Radiation is typically given with androgen suppression when testosterone levels are at their nadir. Recent reports have shown that androgen stimulation of androgen-deprived prostate cancer cells leads to formation of double-strand breaks (DSB). Here, we exploit this finding and investigate the extent and timing of androgen-induced DSBs and their effect on tumor growth following androgen stimulation in combination with ionizing radiation (IR).

EXPERIMENTAL DESIGN

Androgen-induced DNA damage was assessed by comet assays and γH2A.X foci formation. Effects of androgen stimulation and radiation were determined in vitro and in vivo with xenograft models.

RESULTS

We document that androgen treatment of androgen-deprived prostate cancer cell lines resulted in a dose- and time-dependent induction of widespread DSBs. Generation of these breaks was dependent on androgen receptor and topoisomerase II beta but not on cell-cycle progression. In vitro models demonstrated a synergistic interaction between IR and androgen stimulation when IR is given at a time point corresponding with high levels of androgen-induced DSB formation. Furthermore, in vivo studies showed a significant improvement in tumor growth delay when radiation was given shortly after androgen repletion in castrated mice.

CONCLUSIONS

These results suggest a potential cooperative effect and improved tumor growth delay with androgen-induced DSBs and radiation with implications for improving the therapeutic index of prostate cancer radiation therapy. Clin Cancer Res; 22(13); 3310-9. ©2016 AACRSee related commentary by Chua and Bristow, p. 3124.

GSTP1 Loss results in accumulation of oxidative DNA base damage and promotes prostate cancer cell survival following exposure to protracted oxidative stress

BACKGROUND

Epigenetic silencing of glutathione S-transferase π (GSTP1) is a hallmark of transformation from normal prostatic epithelium to adenocarcinoma of the prostate. The functional significance of this loss is incompletely understood. The present study explores the effects of restored GSTP1 expression on glutathione levels, accumulation of oxidative DNA damage, and prostate cancer cell survival following oxidative stress induced by protracted, low dose rate ionizing radiation (LDR).

METHODS

GSTP1 protein expression was stably restored in LNCaP prostate cancer cells. The effect of GSTP1 restoration on protracted LDR-induced oxidative DNA damage was measured by GC-MS quantitation of modified bases. Reduced and oxidized glutathione levels were measured in control and GSTP1 expressing populations. Clonogenic survival studies of GSTP1- transfected LNCaP cells after exposure to protracted LDR were performed. Global gene expression profiling and pathway analysis were performed.

RESULTS

GSTP1 expressing cells accumulated less oxidized DNA base damage and exhibited decreased survival compared to control LNCaP-Neo cells following oxidative injury induced by protracted LDR. Restoration of GSTP1 expression resulted in changes in modified glutathione levels that correlated with GSTP1 protein levels in response to protracted LDR-induced oxidative stress. Survival differences were not attributable to depletion of cellular glutathione stores. Gene expression profiling and pathway analysis following GSTP1 restoration suggests this protein plays a key role in regulating prostate cancer cell survival.

CONCLUSIONS

The ubiquitous epigenetic silencing of GSTP1 in prostate cancer results in enhanced survival and accumulation of potentially promutagenic DNA adducts following exposure of cells to protracted oxidative injury suggesting a protective, anti-neoplastic function of GSTP1. The present work provides mechanistic backing to the tumor suppressor function of GSTP1 and its role in prostate carcinogenesis.