Effect of Pelvic External Beam Radiation Therapy on Bone Mineral Density: A Secondary Analysis of a Phase 3 Randomized Controlled Trial

PURPOSE

Pelvic radiation therapy may lead to decreased bone mineral density (BMD) and increased risk of fracture that could be of particular concern in patients with prostate cancer who also receive androgen deprivation therapy (ADT). We performed an exploratory analysis of a randomized, double-masked, placebo-controlled trial to determine whether exposure to prior pelvic external beam radiation therapy (XRT) affects BMD and risk of fracture in patients with prostate cancer treated with ADT.

METHODS AND MATERIALS

Patients with nonmetastatic prostate cancer aged ≥70 years or <70 years with low BMD (T-score < -1) or osteoporotic fracture who had been receiving ADT for ≥12 months were randomly assigned to receive densoumab or placebo every 6 months for 3 years. BMD was measured at baseline and at months 1, 3, 6, 12, 24, and 36. We applied multivariable linear mixed-effects models with an interaction term between the treatment arm and exposure to prior pelvic XRT to evaluate differential XRT effect on percent BMD change between the 2 treatment arms.

RESULTS

Among 1407 eligible patients, 31% (n = 447) received prior pelvic XRT. There was no significant difference in any clinical fractures among patients with (5.8%, 26 of 447) or without (5.2%, 50 of 960) prior pelvic XRT (P = .42). Prior pelvic XRT was associated with a significant (0.54%) improvement in BMD (95% CI, 0.05-1.02) in the placebo group and a nonsignificant (0.04%) decline in BMD (95% CI, -0.47 to -0.35) in the denosumab group (interaction P = .007). There was no significant difference in pelvic XRT effect on percent BMD change in the lumbar spine (P = .65) or total hip (P = .39) between the 2 treatment groups.

CONCLUSIONS

We did not find sufficient evidence to suggest any detrimental effect of pelvic XRT on the treatment effect from denosumab on percent BMD change, with only an approximately 5% incidence of clinical fractures.

Prostate Radiotherapy in Low-volume Metastatic Hormone-sensitive Prostate Cancer: A Network Meta-analysis

BACKGROUND AND OBJECTIVE

The utility of prostate radiotherapy (RT) is unclear in men with metastatic hormone-sensitive prostate cancer (mHSPC) receiving intensified systemic therapy with androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPIs). We performed a network meta-analysis of randomized controlled trials (RCTs) to investigate the role of prostate RT in low-volume mHSPC.

METHODS

Bibliographic databases and conference proceedings were searched through July 2023 for RCTs evaluating the addition of ARPIs or prostate RT to standard of care (SOC) systemic therapy, defined as ADT or ADT plus docetaxel, for the initial treatment of mHSPC. We focused exclusively on aggregate data from the low-volume mHSPC subpopulation in these trials. We pooled the treatment arms into four groups: SOC, SOC plus ARPI, SOC plus RT, and SOC plus ARPI plus RT. The primary outcome was overall survival (OS). To compare treatment strategies, a fixed-effects Bayesian network meta-analysis was undertaken, while a Bayesian network meta-regression was performed to account for across-trial differences in docetaxel use as part of SOC and in proportions of patients with de novo presentation.

KEY FINDINGS AND LIMITATIONS

Ten RCTs comprising 4423 patients were eligible. The Surface Under the Cumulative Ranking Curve scores were 0.0006, 0.45, 0.62, and 0.94 for SOC, SOC plus RT, SOC plus ARPI, and SOC plus ARPI plus RT, respectively. On a meta-regression, in a population with de novo mHSPC and no docetaxel use, we did not find sufficient evidence of a difference in OS between SOC plus ARPI plus RT versus SOC plus ARPI (hazard ratio [HR]: 0.76; 95% credible interval: 0.51-1.16) and SOC plus RT versus SOC plus ARPI (HR: 1.10; 95% credible interval: 0.92-1.42).

CONCLUSIONS AND CLINICAL IMPLICATIONS

There was some evidence that SOC plus ARPI plus RT reduced mortality compared with the next best strategy of SOC plus ARPI in patients with low-volume de novo mHSPC. A meta-analysis with individual patient data or an RCT is needed to confirm these findings.

Dosimetric impact of rotational errors in trigeminal neuralgia radiosurgery using CyberKnife

PURPOSE

Trigeminal neuralgia (TN) can be treated on the CyberKnife system using two different treatment delivery paths: the general-purpose full path corrects small rotations, while the dedicated trigeminal path improves dose fall-off but does not allow rotational corrections. The study evaluates the impact of uncorrected rotations on brainstem dose and the length of CN5 (denoted as Leff) covered by the prescription dose.

METHODS AND MATERIALS

A proposed model estimates the delivered dose considering translational and rotational delivery errors for TN treatments on the CyberKnife system. The model is validated using radiochromic film measurements with and without rotational setup error for both paths. Leff and the brainstem dose is retrospectively assessed for 24 cases planned using the trigeminal path. For 15 cases, plans generated using both paths are compared for the target coverage and toxicity to the brainstem.

RESULTS

In experimental validations, measured and estimated doses agree at 1%/1 mm level. For 24 cases, the treated Leff is 5.3 ± 1.7 mm, reduced from 5.9 ± 1.8 mm in the planned dose. Constraints for the brainstem are met in 23 cases for the treated dose but require frequent treatment interruption to maintain rotational corrections <0.5° using the trigeminal path. The treated length of CN5, and plan quality metrics are similar for the two paths, favoring the full path where rotations are corrected.

CONCLUSIONS

We validated an analytical model that can provide patient-specific tolerances on rotations to meet plan objectives. Treatment using the full path can reduce treatment time and allow for rotational corrections.

Addressing controversial areas in the management of advanced prostate cancer in Canada Areas of consensus and controversy from the third Canadian consensus forum

INTRODUCTION

The management of prostate cancer (PCa) is rapidly evolving. Treatment and diagnostic options grow annually, however, high-level evidence for the use of new therapeutics and diagnostics is lacking. In November 2022, the Genitourinary Research Consortium held its 3rd Canadian Consensus Forum (CCF3) to provide guidance on key controversial areas for management of PCa.

METHODS

A steering committee of eight multidisciplinary physicians identified topics for discussion and adapted questions from the Advanced Prostate Cancer Consensus Conference 2022 for CCF3. Questions focused on management of metastatic castration-sensitive prostate cancer (mCSPC); use of novel imaging, germline testing, and genomic profiling; and areas of non-consensus from CCF2. Fifty-eight questions were voted on during a live forum, with threshold for "consensus agreement" set at 75%.

RESULTS

The voting panel consisted of 26 physicians: 13 urologists/uro-oncologists, nine medical oncologists, and four radiation oncologists. Consensus was reached for 32 of 58 questions (one ad-hoc). Consensus was seen in the use of local treatment, to not use metastasis-directed therapy for low-volume mCSPC, and to use triplet therapy for synchronous high-volume mCSPC (low prostate-specific antigen). Consensus was also reached on sufficiency of conventional imaging to manage disease, use of germline testing and genomic profiling for metastatic disease, and poly (ADP-ribose) polymerase (PARP) inhibitors for BRCA-positive prostate cancer.

CONCLUSIONS

CCF3 identified consensus agreement and provides guidance on >30 practice scenarios related to management of PCa and nine areas of controversy, which represent opportunities for research and education to improve patient care. Consensus initiatives provide valuable guidance on areas of controversy as clinicians await high-level evidence.

Clinical and radiographic response of a paravertebral hemangioma to radiotherapy

Hemangiomas can arise anywhere in the body. While vertebral hemangiomas are common, atypical hemangiomas with paraspinal and epidural extension are rare. We present a case of a patient who presented with persistent cough and anorexia from a paravertebral hemangioma that invaded the adjacent vertebrae and neural foramen causing moderate spinal canal stenosis. She was treated with stereotactic body radiotherapy to prevent the development of symptomatic spinal cord compression. The hemangioma underwent significant shrinkage and her cough resolved. This case demonstrates impressive and sustained clinical and radiographic response of a paraspinal hemangioma to stereotactic body radiotherapy.

Effect of Concomitant Medications on Treatment Response and Survival in De Novo Metastatic Prostate Cancer: Secondary Analysis of the LATITUDE Study

PURPOSE

It is unclear whether exposure to commonly prescribed medications influences survival and treatment response in patients with de novo high-risk metastatic prostate cancer (mPCa) treated with androgen receptor pathway inhibitors (ARPIs).

METHODS

We performed a secondary analysis of the LATITUDE trial to determine whether receipt of concomitant medications influenced the effect of abiraterone acetate and prednisone, in addition to androgen deprivation therapy (ADT), on overall survival (OS) and prostate cancer-specific mortality (PCSM) in patients with de novo mPCa. We focused on 7 commonly prescribed classes of medications: metformin, statins, proton pump inhibitors (PPIs), cyclooxygenase 2 (COX-2) inhibitors, aspirin, acetaminophen, and NSAIDs (nonselective COX inhibitors). To account for multiple testing, a two-sided p < 0.0024 was set as the threshold for statistical significance.

RESULTS

Overall, 1135 patients were eligible. There was some evidence of a differential treatment effect from abiraterone among patients who received concomitant NSAIDs (hazard ratio [HR] for OS: 0.54; 95% CI: 0.42-0.70) versus those who did not (HR: 0.74; 95% CI: 0.60-0.91), though this did not reach significance (interaction p = 0.05). A similar non-significant finding of heterogeneity of effect from abiraterone was noted among patients who received concomitant aspirin (HR for OS: 0.93 [0.63-1.36]) versus those who did not (HR: 0.61 [0.51-0.73]) (interaction p = 0.04). Receipt of NSAIDs was independently associated with a significantly inferior OS (HR: 1.37 [1.15-1.62]; p < 0.001) and higher relative incidence of PCSM (sHR: 1.47 [1.21-1.78]; p < 0.001).

CONCLUSIONS

This exploratory analysis did not find statistically significant evidence of differences in treatment effects from ADT plus abiraterone in de novo high-risk mPCa based on the receipt of concurrent medications. The receipt of NSAIDs was independently associated with increased PCSM and inferior OS.

Understanding Oral PrEP Interest, Uptake, Persistence, and Experience of Use Among Heterosexual Men in Johannesburg, South Africa: An Exploratory Pilot Study

South Africa's PrEP programming has primarily focused on men who have sex with men and other key populations through dedicated clinical and outreach services. However, data shows that the pool of men vulnerable to contracting HIV extends beyond this group, including men who have sex only with women and who do not identify as gay. The aim of this pilot study was to assess acceptability of PrEP among this subset of men who are at risk of HIV acquisition in South Africa and to describe the demographic and behavioral characteristics of male PrEP users as well as their experience of PrEP use. We employed a mixed-methods study design consisting of in-depth interviews and quantitative analysis of routine clinic data collected between September 2021 and February 2022 from 10 private health facilities. Men who enrolled in the study and initiated PrEP had low consistent condom use and nearly three quarters reported more than one sexual partner in the past three months. Despite minimal follow-up support, PrEP persistence was relatively high and similar to other populations. 57% of men returned for their 1-month visit, 40% returned for their 4-month visit, and 16% returned for their 7-month visit. The greatest barriers to ongoing use were the need to take a daily pill and low perceived HIV risk. To improve uptake and continuation, programs should increase awareness of PrEP, leverage trusted sources to build credibility, make access more convenient, and accommodate flexible use through event-driven PrEP.

A review of stereotactic ablative radiotherapy for nonmetastatic renal cell carcinoma

Renal cell carcinoma (RCC) is an uncommon malignancy whose incidence has been increasing over the past few decades, posing treatment challenges for elderly or infirm patients who are not surgical candidates. Stereotactic ablative radiotherapy (SABR) has emerged as a promising non-invasive treatment modality for RCC. The high dose-per-fraction used in SABR overcomes some of the mechanisms of radioresistance that has hindered the effective treatment of RCC with conventional radiotherapy. For primary RCC, local control rates for SABR exceed 90%, with typically minimal grade 3 or higher toxicities, offering a viable alternative for inoperable patients and those not eligible for or unable to tolerate radiofrequency or cryotherapy ablation. SABR can also be used in patients with a solitary kidney as a strategy for renal preservation to avoid need for dialysis. Given its excellent local control rates, low toxicity and preservation of renal function, SABR offers an attractive alternative to more invasive modalities for treatment of localized RCC.

Association of PSA kinetics after testosterone recovery with subsequent recurrence: secondary analysis of a phase III randomized controlled trial

PURPOSE

After cessation of androgen deprivation therapy (ADT), testosterone gradually recovers to supracastrate levels (> 50 ng/dL). After this, rises in prostate-specific antigen (PSA) are often seen. However, it remains unknown whether early PSA kinetics after testosterone recovery are associated with subsequent biochemical recurrence (BCR).

METHODS

We performed a secondary analysis of a phase III randomized controlled trial in which newly diagnosed localized prostate cancer patients were randomly allocated to ADT for 6 months starting 4 months prior to or simultaneously with prostate RT. We calculated the PSA doubling time (PSADT) based on PSA values up to 18 months after supracastrate testosterone recovery. Competing risk regression was used to evaluate the association of PSADT with relative incidence of BCR, considering deaths as competing events.

RESULTS

Overall, 313 patients were eligible. Median PSADT was 8 months. Cumulative incidence of BCR at 10 years from supracastrate testosterone recovery was 19% and 11% in patients with PSADT < 8 months and ≥ 8 months (p = 0.03). Compared to patients with PSADT of < 4 months, patients with higher PSADT (sHR for PSADT 4 to < 8 months: 0.36 [95% CI 0.16-0.82]; 8 to < 12 months: 0.26 [0.08-0.91]; ≥ 12 months: 0.20 [0.07-0.56]) had lower risk of relative incidence of BCR.

CONCLUSIONS

Early PSA kinetics, within 18 months of recovery of testosterone to a supracastrate level, can predict for subsequent BCR. Taking account of early changes in PSA after testosterone recovery may allow for recognition of potential failures earlier in the disease course and thereby permit superior personalization of treatment.

Impact of sequencing of androgen receptor-signaling inhibition and radiotherapy in prostate cancer: importance of homologous recombination disruption

PURPOSE

The synergy of combining androgen receptor-signaling inhibition (ARSI) to radiotherapy (RT) in prostate cancer has been largely attributed to non-homologous end joining (NHEJ) inhibition. However, this mechanism is unlikely to explain recently observed trial results that demonstrated the sequencing of ARSI and RT significantly impacts clinical outcomes, with adjuvant ARSI following RT yielding superior outcomes to neoadjuvant/concurrent therapy. We hypothesized this is driven by differential effects on AR-signaling and alternative DNA repair pathway engagement based on ARSI/RT sequencing.

METHODS

We explored the effects of ARSI sequencing with RT (neoadjuvant vs concurrent vs adjuvant) in multiple prostate cancer cell lines using androgen-deprived media and validation with the anti-androgen enzalutamide. The effects of ARSI sequencing were measured with clonogenic assays, AR-target gene transcription and translation quantification, cell cycle analysis, DNA damage and repair assays, and xenograft animal validation studies.

RESULTS

Adjuvant ARSI after RT was significantly more effective at killing colony forming cells and decreasing the transcription and translation of downstream AR-target genes across all prostate cancer models evaluated. These results were reproduced in xenograft studies. The differential effects of ARSI sequencing were not fully explained by NHEJ inhibition alone, but by the additional disruption of homologous recombination specifically with adjuvant sequencing of ARSI.

CONCLUSION

We demonstrate that altered sequencing of ARSI and RT mediates differential anti-AR-signaling and anti-cancer effects, with the greatest benefit from adjuvant ARSI following RT. These results, combined with our prior clinical findings, support the superiority of an adjuvant-based sequencing approach when using ARSI with RT.

Genetic testing practices among specialist physicians who treat prostate cancer A Canadian, cross-sectional survey

INTRODUCTION

In patients with prostate cancer (PCa), the identification of an alteration in genes associated with homologous recombination repair (HRR) has implications for prognostication, optimization of therapy, and familial risk mitigation. The aim of this study was to assess the genomic testing landscape of PCa in Canada and to recommend an approach to offering germline and tumor testing for HRR-associated genes.

METHODS

The Canadian Genitourinary Research Consortium (GURC) administered a cross-sectional survey to a largely academic, multidisciplinary group of investigators across 22 GURC sites between January and June 2022.

RESULTS

Thirty-eight investigators from all 22 sites responded to the survey. Germline genetic testing was initiated by 34%, while 45% required a referral to a genetic specialist. Most investigators (82%) reported that both germline and tumor testing were needed, with 92% currently offering germline and 72% offering tissue testing to patients with advanced PCa. The most cited reasons for not offering testing were an access gap (50%), uncertainties around who to test and which genes to test, (33%) and interpreting results (17%). A majority reported that patients with advanced PCa (74-80%) should be tested, with few investigators testing patients with localized disease except when there is a family history of PCa (45-55%).

CONCLUSIONS

Canadian physicians with academic subspecialist backgrounds in genitourinary malignancies recognize the benefits of both germline and somatic testing in PCa; however, there are challenges in accessing testing across practices and specialties. An algorithm to reduce uncertainty for providers when ordering genetic testing for patients with PCa is proposed.

Impact of Prior Radiation Therapy on Bone Mineral Density Change Over Time: Secondary Analysis of the Control Arm of a Phase III Randomized Trial

PURPOSE/OBJECTIVE(S)

Retrospective studies have demonstrated that pelvic radiation therapy (RT) can lead to decreased bone mineral density (BMD) and increased risk of fracture. This is more relevant for men with prostate cancer (PCa) who often receive androgen deprivation therapy (ADT) in conjunction with RT. We performed a post-hoc secondary analysis of publicly available data of the control arm of a phase III randomized controlled study (NCT00089674) to determine if history of prior pelvic RT affects change in BMD over time in non-metastatic PCa patients treated with ADT.

MATERIALS/METHODS

In this study, PCa patients with age ≥70 years or <70 years with low BMD (T-score <-1) or history of osteoporotic fracture, on ADT for at least 12 months were randomized to receive densoumab vs. placebo every 6 months for 3 years. Additionally, all patients received daily vitamin D and calcium supplementation. Randomization was stratified by duration of prior ADT (≤6 months vs >6 months) and age (<70 vs ≥70 years). BMD was measured at baseline, and at months 1, 3, 6, 12, 24, and 36 with blind reading by central reviewer. To model the effect of prior pelvic RT on dynamic change in BMD in the hip, lumbar spine, and femoral neck, we applied separate multivariate linear mixed effect models for each site. Age, ECOG performance score, history and number of prior fractures, smoking history, and years from initial cancer diagnosis were included as fixed covariates while patients were included as random intercepts.

RESULTS

Among 734 patients who were randomized to the control arm, 563 participants with baseline and at least one post baseline assessment of BMD were eligible for this analysis. Overall, 34.4% (n = 194) received prior RT. We did not find any significant association of dynamic change in BMD with receipt of prior pelvic RT for left femoral neck (p = 0.7), total hip (p = 0.8), and lumbar spine (p = 0.5), respectively. At 36 months, there was no significant association of prior RT with percent change in BMD in femoral neck (odds ratio [OR]: 0.85; 95% confidence interval [CI]: 0.30-2.41), total hip (OR: 0.96; 95% CI: 0.43-2.15), and lumbar spine (OR: 2.01; 95% CI: 0.63-6.45). However, note should be made of the opposite direction of association of prior RT with percent BMD change at 36 months for femoral neck and hip versus lumbar spine.

CONCLUSION

In this exploratory analysis of the control arm of a phase III randomized trial, we did not find sufficient evidence of an association between prior pelvic RT and dynamic changes in BMD in femoral neck, hip, and lumbar spine over time in men with non-metastatic PCa and low BMD at baseline. This analysis should be interpreted cautiously considering its post-hoc nature with likely inadequate power, the possibility of selection bias, lack of information on receipt of prior ADT, and missing data in longitudinal assessments.

Association of Prostate Specific Antigen Kinetics after Testosterone Recovery with Subsequent Recurrence: Secondary Analysis of a Phase III Randomized Controlled Trial

PURPOSE/OBJECTIVE(S)

The combination of short-term androgen deprivation therapy (ST-ADT) with prostate radiotherapy (RT) is a standard of care for patients with localized prostate cancer (LPCa). After cessation of ST-ADT, it takes about 8 to 10 months for the testosterone (T) to recover to supracastrate levels, which could drive changes in PSA kinetics. It largely remains unknown whether early changes in PSA kinetics after T recovery could predict for subsequent biochemical relapse.

MATERIALS/METHODS

We performed a secondary analysis of a phase III randomized controlled trial in which patients with newly diagnosed LPCa with Gleason score £7, clinical stage T1b to T3a, and PSA <30 ng/mL were randomly allocated to neoadjuvant and concurrent ADT for 6 months starting 4 months before prostate RT (76 Gy in 38 fractions over 7.5 weeks) or concurrent and adjuvant ADT for 6 months starting simultaneously with prostate RT. Clinical assessment and laboratory investigations were repeated 1 month after completion of ADT, every 4 months for the first 2 years, every 6 months for the next 3 years, and annually thereafter. We calculated the PSA doubling time (PSADT) based on PSA values up to 18 months after recovery of T to a supracastrate level (>50 ng/dL). Patients with ³3 PSA measurements after T recovery to supracastrate level were included in this analysis. Fine and Gray cumulative incidence of biochemical recurrence (BCR) was calculated in patients with PSADT at or above median versus below median. Deaths were considered as competing events. All endpoints were calculated from the time of T recovery to supracastrate level. Subdistribution hazard ratios (sHR) with 95% confidence intervals (CI) were estimated for association of PSADT with relative incidence of recurrence using competing risk regression after adjusting for tumor stage, pre-treatment PSA, Gleason score, treatment regimen, and age at randomization.

RESULTS

Overall, 311 patients were eligible for this analysis. Median PSADT was 8 months. Cumulative incidence of BCR at 10 years was 31.0% and 20.7% in patients with PSADT <8 months and ³8 months, respectively. Longer PSADT was associated with a significantly lower risk of cumulative incidence of BCR (sHR for PSADT as a continuous variable 0.43, 95% CI: 0.28-0.66; sHR for PSADT ³8 months 0.54, 95% CI: 0.30-0.99). After adjustment for time to recovery of T to supracastrate level in addition to the aforementioned variables, longer PSADT (³8 months) was associated with lower risk of cumulative incidence of BCR (sHR: 0.53, 95% CI: 0.27-1.01).

CONCLUSION

These findings suggest that early PSA kinetics within 18 months of recovery of T to a supracastrate level predict for subsequent biochemical failure. Taking account of early changes in PSA after testosterone recovery may allow for recognition of potential failures earlier in the disease course and thereby permit greater personalization of management decisions.

Prognostic Role of Dynamic Changes in Serological Markers in Metastatic Hormone Naïve Prostate Cancer

We investigated whether inter-patient variation in the dynamic trajectory of hemoglobin (Hb), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), lymphocyte to monocyte ratio (LMR), and prostate-specific antigen (PSA) can prognosticate overall survival (OS) in de novo mHSPC. This is a secondary analysis of the LATITUDE trial in which high-risk de novo mHSPC patients were randomly assigned to receive either androgen deprivation therapy (ADT) plus abiraterone or ADT plus placebo. We used a five-fold cross-validated joint model approach to determine the association of temporal changes in the serological markers with OS. Decision curve analysis was applied to determine the net benefit. When dynamic changes in Hb, LMR, NLR, PLR, and PSA were included in a multivariate joint model, an increase in the log of the current value of PSA (HR: 1.24 [1.20-1.28]) was associated with inferior OS. A multivariate joint model that captured dynamic trajectory of Hb, NLR, PLR, LMR, and PSA up to 24 months, showed a net benefit over the "treat all" strategy at a threshold of probability of approximately ≥30% while no net benefit was seen when dynamic change in PSA was omitted. Our joint model could be used for designing future adaptive trials investigating sequential treatment personalization.

Effect of Prior Local Therapy on Response to First-line Androgen Receptor Axis Targeted Therapy in Metastatic Castrate-resistant Prostate Cancer: A Secondary Analysis of the COU-AA-302 Trial

BACKGROUND

Men with localized prostate cancer are often treated with local therapy (LT). However, a proportion of these patients will eventually develop recurrence and progression requiring systemic therapy. Whether primary LT affects the response to this subsequent systemic treatment is unclear.

OBJECTIVE

We investigated whether the receipt of prior prostate-directed LT influenced the response to first-line systemic therapy and survival in docetaxel-naïve metastatic castrate-resistant prostate cancer (mCRPC) patients.

DESIGN, SETTING, AND PARTICIPANTS

This is an exploratory analysis of the COU-AA-302 trial, a multicentric double-blinded phase 3 randomized controlled trial in which mCRPC patients with no to mild symptoms were randomized to receive abiraterone plus prednisone or placebo plus prednisone.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We compared the time-varying effects of first-line abiraterone in patients with and without prior LT using a Cox proportional hazard model. The cut points were chosen using grid search, and were 6 and 36 mo for radiographic progression-free survival (rPFS) and overall survival (OS), respectively. We also investigated whether there was any difference in treatment effect on score change (relative to baseline) in various patient-reported outcomes (measured by Functional Assessment of Cancer Therapy-Prostate [FACT-P]) over time depending on the receipt of prior LT. The adjusted association of prior LT with survival was determined using weighted Cox regression models.

RESULTS AND LIMITATIONS

Among 1053 eligible patients, 64% (n = 669) received prior LT. We did not find any statistically significant heterogeneity of time-dependent treatment effect from abiraterone on rPFS in patients with (hazard ratio [HR]: 0.36 [95% confidence interval: 0.27-0.49] at ≤6 mo; 0.64 [0.49-0.83] at >6 mo) or without (HR: 0.37 [0.26-0.55] at ≤6 mo; 0.72 [0.50-1.03] at >6 mo) prior LT. Similarly, there was no significant heterogeneity in time-dependent treatment effect on OS with (HR: 0.88 [0.71-1.10] at ≤36 mo; 0.76 [0.52-1.11] at >36 mo) or without (0.78 [0.60-1.01] at ≤36 mo; 0.55 [0.30-0.99] at >36 mo) prior LT. We did not find sufficient evidence of a difference in treatment effect from abiraterone on score change over time in prostate cancer subscale (interaction p = 0.4), trial outcome index (interaction p = 0.8), and FACT-P total score (interaction p = 0.6) depending on the receipt of prior LT. Receipt of prior LT was associated with a significant improvement in OS (average HR: 0.72 [0.59-0.89]).

CONCLUSIONS

This study demonstrates that the efficacy of first-line abiraterone and prednisone in docetaxel-naïve mCRPC do not vary significantly based on the receipt of prior prostate-directed LT. Further studies are needed to explore the plausible mechanisms of the association of prior LT with superior OS.

PATIENT SUMMARY

This secondary analysis of the COU-AA-302 trial suggests that survival benefits and temporal changes in quality of life with first-line abiraterone in docetaxel-naïve mCRPC do not differ significantly among patients who received versus those who did not receive prior prostate-directed local therapy.

Implications of metastatic stage at presentation in docetaxel naïve metastatic castrate resistant prostate cancer

BACKGROUND

We performed a secondary analysis of ACIS study to determine if synchronous versus metachronous metastatic presentation has any association with survival and treatment response to dual androgen receptor axis-targeted therapy (ARAT) in docetaxel naïve metastatic castrate resistant prostate cancer (mCRPC).

METHODOLOGY

In this phase III randomized controlled trial, docetaxel naïve mCRPC patients were randomized to either apalutamide or placebo combined with abiraterone and prednisone. Multivariable Cox regression models were applied to determine the adjusted association of M-stage with radiographic progression-free survival (rPFS) and overall survival (OS). To determine the heterogeneity of treatment effect based on metastatic stage (M-stage) at presentation, Cox regression was applied with interaction terms between M-stage and treatment.

RESULTS

Among 972 patients, 432 had M0, 334 had M1, while M-stage at presentation was unknown in 206. There was no association of M-stage at presentation with rPFS in patients with prior local therapy (LT) (hazard ratio for M1-stage: 1.22 [95% confidence interval: 0.82-1.82]; unknown: 1.03 [0.77-1.38]) or without prior LT (M1-stage: 0.87 [0.64-1.19]; unknown: 1.15 [0.77-1.72]) with no significant heterogeneity. Similarly, there was no association of M-stage with OS in patients with prior LT (M1-stage: 1.04 [0.81-1.33]; unknown: 0.98 [0.79-1.21]) or without prior LT (M1-stage: 0.95 [0.70-1.29]; unknown: 1.17 [0.80-1.71]) with no significant heterogeneity. Based on M-stage at presentation, we did not find any significant heterogeneity in treatment effect on rPFS (interaction p = 0.13), and OS (interaction p = 0.87).

CONCLUSION

M-stage at presentation had no association with survival in chemotherapy-naïve mCRPC. We did not find any statistically significant heterogeneity in efficacy of dual ARAT based on synchronous versus metachronous presentation.

Development and validation of a multivariable prognostic model in de novo metastatic castrate sensitive prostate cancer

BACKGROUND

Metastatic castrate sensitive prostate cancer (mCSPC) is a heterogeneous disease state with variable prognosis. Although several life-prolonging systemic agents are available, there is no robust multivariable model to predict prognosis and improve risk stratification in mCSPC. The objective of this study was to build and validate a multivariable prognostic model to predict overall survival (OS) in mCSPC.

METHODS

We used data from LATITUDE, a phase III randomized controlled trial in which men with de novo mCSPC were randomly allocated to either ADT plus abiraterone or ADT with placebo. Patients with non-missing data (n = 1,058) were randomly split in a 70:30 ratio to training (n = 743) and testing (n = 315) sets. Elastic net regression was used for variable selection. A multivariable Cox regression model for OS was then fitted using the selected variables. The predictive accuracy of the model was assessed on the testing set using the time-dependent area under curve (tAUC) with bootstrapped confidence intervals [CI] primarily for OS and secondarily for radiographic progression-free survival (rPFS).

RESULTS

The 11 prognostic variables in the final model were performance status, number of skeletal metastases, Gleason score, presence of liver metastasis, worst pain score, albumin, lactate dehydrogenase, prostate-specific antigen, hemoglobin, and treatment regimen. The tAUC for predicting OS at 2- and 3-years was 0.74 (95% CI, 0.67-0.80) and 0.72 (95% CI, 0.65-0.77), respectively. The tAUC for rPFS at 2- and 3-years was 0.72 (95% CI, 0.65-0.77) and 0.77 (95% CI, 0.70-0.82), respectively.

CONCLUSIONS

A prognostic model for men with de novo mCSPC was developed and validated in an independent testing set. Our model had high accuracy for predicting OS and rPFS. The model includes commonly used clinical and laboratory parameters and can guide risk stratification of these patients for participation in future trials.

Association of dynamic change in patient-reported pain with survival in metastatic castrate sensitive prostate cancer-exploratory analysis of LATITUDE study

BACKGROUND

Pain is an important dimension of quality-of-life in patients with metastatic castrate-sensitive prostate cancer (mCSPC). However, it is unclear if dynamic change in pain over time can predict for overall survival (OS) or progression-free survival (PFS) in these patients.

METHODS

This is an exploratory analysis of LATITUDE, a phase III randomized study, in which men with de novo mCSPC were randomized to receive either ADT plus abiraterone versus ADT alone. Information was collected on patient-reported worst pain score (WPS) and pain-interference score (PIS) from the Brief Pain Inventory-Short Form. A Bayesian joint modelling approach was used determine the association of dynamic change in WPS and PIS with OS and PFS.

RESULTS

Overall, 1125 patients with at least 3 measurements on pain scores were eligible. On Cox multivariable regression, increase in baseline WPS was associated with inferior OS (hazard ratio [HR] 1.049 [95% confidence intervals [CI] 1.015-1.085]; time dependent area under curve [tAUC] 0.64) and PFS (HR 1.045 [1.011-1.080]; tAUC: 0.64). Increase in baseline PIS was associated with inferior OS (HR 1.062 [1.020-1.105]; tAUC: 0.63) but not with PFS (HR 1.038 [0.996-1.08]). On independent joint models, an increase in the current value of WPS by 1-unit was associated with inferior OS (HR 1.316 [1.258-1.376]; tAUC 0.74) and PFS (HR 1.319 [1.260-1.382]; tAUC 0.70). Similar association was seen for increase in the current value of PIS with OS (HR 1.319 [1.261-1.381]; tAUC 0.73) and PFS (HR 1.282 [1.224-1.344]; tAUC 0.73).

CONCLUSIONS

The above findings highlight the potential dynamic interplay between patient-reported pain with OS and PFS in mCSPC. Compared to baseline pain, such dynamic assessment of pain was found to have superior predictive ability and thus has the potential to tailor subsequent treatment based on response to initial therapy beyond its role as a very important dimension of quality-of-life.

Real-world utilization and outcomes of docetaxel among older men with metastatic prostate cancer: a retrospective population-based cohort study in Canada

BACKGROUND

The adoption of docetaxel for systemic treatment of metastatic prostate cancer (PCa), in both castration-sensitive (mCSPC) and castration-resistant (mCRPC) settings, is poorly understood. This study examined the real-world utilization of docetaxel in these patients and their outcomes.

METHODS

A retrospective population-based study used administrative data from Ontario, Canada, to identify men aged ≥66 years who were diagnosed with de novo mCSPC or mCRPC between 2014 and 2019 and received docetaxel. The study assessed treatment tolerability and toxicity, and survival in both cohorts. Descriptive and comparative statistical analysis were conducted.

RESULTS

The study identified 11.2% (399/3556) and 13.2% (203/1534) patients diagnosed with de novo mCSPC and with mCRPC who received docetaxel respectively. The median age in both cohorts was 72 years (IQR: 68-76). Overall, 43.9% (n = 175) patients with de novo mCSPC and 52.1% (n = 85) with mCRPC completed ≥6 cycles of docetaxel. Over two-fifth also needed dose adjustments in both cohorts. Hospitalization or emergency department visit for febrile neutropenia were noted in 15.8% (n = 63) of de novo mCSPC patients and similarly in 19% (n = 31) of mCRPC cohort. The median survival of PCa patients who completed ≥6 cycles of docetaxel was significantly longer relative to those who completed <4 cycles: 32.7 vs. 23.5 months (p < 0.001) for mCSPC and 20.5 vs. 10.7 (p = 0.012) for mCRPC respectively.

CONCLUSIONS

In this population-based study of elderly patients with metastatic PCa, treatment with docetaxel was associated with poor tolerability and higher toxicity compared with clinical trials. Receipt of limited cycles and reduced overall dose of docetaxel were associated with inferior overall survival.

Radiographic progression-free survival (rPFS) and time to radiographic progression (TTrP) as surrogate endpoints in docetaxel-naïve metastatic castrate resistant prostate cancer (mCRPC): A pooled analysis of COU-AA-302 and ACIS

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Background: rPFS is often used as an intermediate clinical endpoint (ICE) for overall survival (OS) in randomized trials in mCRPC. However, the current literature shows conflicting results on the surrogacy of rPFS for OS. Moreover, it remains unknown if TTrP, which does not consider death as an event, is an ICE for OS. We performed a combined analysis of COU-AA-302 and ACIS to determine if TTrP and rPFS can be used as ICE. Methods: In COU trial, docetaxel-naïve mCRPC patients were randomized to abiraterone (abi) versus placebo. In ACIS, a similar patient population was randomized to abi alone or abi with apalutamide (abi+apa). We applied weighted Cox regression models to evaluate the effect of treatment on TTrP and OS and used landmark analyses to determine the if the treatment effect on OS is mediated by that on radiographic progression. We estimated a semiparametric Spearman correlation between the ICE and OS at the patient level. We determined the trial level correlation of treatment effect on the ICE and OS in the 2 trials where each of them was subdivided into 9 pseudo-trial centers and then calculating the adjusted R2 between center level estimates of treatment effect for ICE and OS. The procedure of creating pseudo-trial centers was repeated 500 times and the presented R2 is the average across 500 repetitions after excluding those with negative association. Results: Overall, 2016 patients were eligible for this study – 1053 from COU and 963 from ACIS. Abi was associated with superior TTrP (HR 0.55 [95%CI 0.45-0.66]) and OS (HR 0.80 [0.70-0.92]). Similar results were seen with abi+apa (0.51 [0.41-0.64], 0.77 [0.65-0.91]). Radiographic progression was associated with significantly higher hazard of death in the state arrival extended Markov proportional hazard model (3.64 [1.54-8.62]) while longer TTrP was associated with reduced hazard of death (0.94 [0.93-0.95]). At the patient level, the correlation between TTrP & OS and rPFS & OS was 0.58 [0.54-0.63] and 0.68 [0.65-0.71], in the overall cohort. In the abi and abi+apa group, the correlation between TTrP and OS was 0.60 [0.53-0.66] and 0.73 [0.66-0.79] and that for rPFS and OS was 0.72 [0.67-0.75] and 0.79 [0.74-0.83], respectively. At the trial level, the treatment effect on rPFS & OS and TTrP & OS were correlated with average R2 of 0.84, 0.84, 0.85, and 0.86, respectively. The mean surrogate threshold effect over 500 permutations for HRrPFS and HRTTrP was 0.78 and 0.70 in ACIS and 0.54 and 0.45 in the COU-AA-302 trials, respectively. Conclusions: TTrP and rPFS were found to have significant association with OS in chemo-naïve mCRPC patients. We noted a modest to strong correlation between the treatment effect on both the ICE and OS at the trial level. Larger meta-analytic studies are needed to validate these findings.

Testosterone Recovery Following Androgen Suppression and Prostate Radiotherapy (TRANSPORT): Individual patient data meta-analysis from the MARCAP Consortium

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Background: The kinetics of testosterone recovery (TR) vary following cessation of androgen deprivation therapy (ADT) of various durations when given in combination with radiotherapy for prostate cancer. Time to TR will impact on quality of life. We aim to identify factors affecting the time to TR following ADT use. Methods: We included trials of prostate radiotherapy and ADT in the Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) consortium for which prospectively collected serial testosterone data is available. Time to non-hypogonadal TR (NHTR) (>8.0nmol/L) and time to full TR (FTR) (>10.5nmol/L) were estimated from the date of first available testosterone at trial enrolment to the date of TR using the Kaplan-Meier method. The effect of interactions between duration of ADT and patients’ age on TR was evaluated. Results: There were 1439 men with non-castrate testosterone at baseline (>1.7nmol/L) who met the inclusion criteria for analysis, of which 220, 765 and 454 men had 3-, 6-, and 18-months of ADT. There were 959 (67%) men who had FTR at last follow-up. For men who had 3-, 6-, and 18-months of ADT, the median time (range) to NHTR were 5.5 (1.6-76.3), 12.2 (0.8-53.6), and 30.1 (2.8-90.4) months respectively, while the median time (range) to FTR were 6.2 (1.8-75.7), 15.2 (0.8-86.0), and 36.0 (18.1-85.5) months respectively. In the subset of 1160 men who had normal testosterone at baseline (>10.5nmol/L), 851 (69%) men had FTR, with a median time (range) to FTR of 5.5 (1.8-75.7), 12.7 (1.8-86.0), and 30.8 (18.1-84.1) months for men who had 3-, 6- and 18-months ADT, respectively. For any given duration of ADT, men aged above 65 years were less likely to have FTR compared to those aged under 65 years – HR=0.67 (95%CI=0.46-0.99), HR=0.80 (95%CI=0.67-0.96), HR=0.64 (95%CI=0.51-0.81) for men who had 3-, 6-, and 18-months ADT respectively. There was no evidence of interaction between the effect of ADT duration on time to FTR and age (interaction P=0.3 for entire cohort). Conclusions: This is the largest pooled analysis of prospectively collected serial testosterone data from randomized trials, indicating substantial delay in FTR in men receiving longer durations of ADT. Approximately one-third of the men did not achieve FTR, which may have life-long impact on quality of life.

Pelvic clinical node-positive prostate cancer: Impact of radiotherapy and nodal disease burden

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Background: The optimal management of pelvic clinical node-positive (cN1) prostate cancer remains controversial and randomized evidence for local therapy is lacking. Recent data suggests that common iliac nodal metastases (CIM), while technically constituting M1a disease, are more common than previously recognized and might carry a prognosis similar to that of cN1 disease when treated radically. In this context, we reviewed the experience at our center of treating cN1 prostate cancer, with or without CIM, focusing on the role of radiotherapy (RT) and measures of nodal disease burden. Methods: The study population consisted of men diagnosed between 2002 and 2018 with prostate cancer with cN1 disease and/or CIM and treated with androgen deprivation therapy and/or definitive local therapy. Outcomes of interest included overall survival (OS) and castration resistance-free survival (CRFS), which were estimated using the Kaplan-Meier method. Univariate and multivariate Cox regression were used to identify factors associated with OS and CRFS. In the subgroup of patients treated with RT, the association between a number of RT characteristics – including biologically effective dose (BED) to the prostate, use of elective pelvic nodal RT, and escalated dose (RT boost) to positive nodes – and OS was studied. Results: A total of 87 patients were included, of whom 14 had CIM and 68 received RT. Median follow-up was 110 months. On univariate analysis, RT was associated with improved OS (hazard ratio [HR] 0.28, 95% CI 0.14-0.55, p<0.0005) and CRFS (HR 0.22, 95% CI 0.12-0.41, p<0.0005). Median OS in patients receiving RT was 134.9 months versus 63.1 months in those not receiving RT. Receipt of RT remained significantly associated with OS on multivariate analysis (HR 0.12, 95% CI 0.05-0.31, p<0.001). Biopsy Gleason score 10 and presence of >2 positive lymph nodes were associated with worse OS while presence of CIM was not associated with OS. In patients treated with RT, increasing BED to the prostate was associated with improved OS (HR 0.73 per 10 Gy increase, 95% CI 0.54-0.97, p=0.03) while use of elective pelvic nodal RT and use of an RT boost to positive nodes were not associated with OS. Conclusions: This is the first cohort to evaluate the impact of RT in pelvic clinical node-positive prostate cancer that includes CIM. Receipt of RT was associated with improved oncologic outcomes. The number of positive pelvic nodes, but not their common iliac location, was prognostic and warrants further investigation in a larger dataset.

Practice patterns and predictors of treatment intensification in patients with metastatic castration-sensitive prostate cancer

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Background: In recent years, treatment intensification beyond androgen deprivation therapy (ADT) with several novel therapies have shown survival benefit in patients with metastatic castration-sensitive prostate cancer (mCSPC). Given the rapidly evolving landscape in mCSPC treatment, there is a need to better understand how treatment strategies fit in real-world clinical practice and are combined/sequenced with other available therapies. Methods: Using electronic medical records and administrative data, a population-based retrospective cohort study was conducted. Patients aged ≥18 years of age who were newly diagnosed with de novo mCSPC and initiated ADT post-diagnosis between 2010 to 2020 in Alberta, Canada, were included. Treatment intensification was defined as the receipt of apalutamide, abiraterone acetate, enzalutamide, or chemotherapy (e.g. docetaxel) within 180 days of ADT initiation. Results: A total of 2,515 de novo mCSPC were identified during study period with 2,098 (83%) patients initiating ADT post-diagnosis. Of those, 525 (25%) received intensification beyond ADT. The percentage of patients who were intensified was 3% in 2010-2013 and gradually increased to 67% in 2020. Between 2014-2017, docetaxel was the most common therapy for intensification, but its use decreased considerably in 2018-2020 with abiraterone acetate, apalutamide and enzalutamide becoming increasingly available in the mCSPC setting. Upon progression, 46% and 22% in the intensified group versus 38% and 13% in the ADT-alone group initiated one and two-lines of subsequent therapies respectively. Abiraterone acetate and enzalutamide were the most common subsequent therapy for both the intensified (32% and 31% respectively) and the ADT-alone (56% and 38% respectively) groups. Docetaxel (24%) was used as subsequent therapy among mCSPC patients who were intensified with oral systemic agents. In multivariable logistic regression analyses of patients diagnosed in 2014-2020, significant predictors of intensification were younger age at diagnosis, lower Charlson comorbidity index, greater number of metastatic sites, shorter time to ADT initiation, referral to a specialists/cancer centres, surgery or radiation prior to ADT, and more recent year of diagnosis (all p<0.05). Conclusions: In Alberta, Canada, there has been a considerable increase in the utilization of ADT intensification therapies that correspond with the timing of clinical trial data and approvals of novel agents. Early referral to specialists/cancer centres is warranted to intensify mCSPC treatment beyond ADT and to improve patients’ outcomes. [Table: see text]

Sequencing of Androgen-Deprivation Therapy of Short Duration With Radiotherapy for Nonmetastatic Prostate Cancer (SANDSTORM): A Pooled Analysis of 12 Randomized Trials

PURPOSE

The sequencing of androgen-deprivation therapy (ADT) with radiotherapy (RT) may affect outcomes for prostate cancer in an RT-field size-dependent manner. Herein, we investigate the impact of ADT sequencing for men receiving ADT with prostate-only RT (PORT) or whole-pelvis RT (WPRT).

MATERIALS AND METHODS

Individual patient data from 12 randomized trials that included patients receiving neoadjuvant/concurrent or concurrent/adjuvant short-term ADT (4-6 months) with RT for localized disease were obtained from the Meta-Analysis of Randomized trials in Cancer of the Prostate consortium. Inverse probability of treatment weighting (IPTW) was performed with propensity scores derived from age, initial prostate-specific antigen, Gleason score, T stage, RT dose, and mid-trial enrollment year. Metastasis-free survival (primary end point) and overall survival (OS) were assessed by IPTW-adjusted Cox regression models, analyzed independently for men receiving PORT versus WPRT. IPTW-adjusted Fine and Gray competing risk models were built to evaluate distant metastasis (DM) and prostate cancer-specific mortality.

RESULTS

Overall, 7,409 patients were included (6,325 neoadjuvant/concurrent and 1,084 concurrent/adjuvant) with a median follow-up of 10.2 years (interquartile range, 7.2-14.9 years). A significant interaction between ADT sequencing and RT field size was observed for all end points (P interaction < .02 for all) except OS. With PORT (n = 4,355), compared with neoadjuvant/concurrent ADT, concurrent/adjuvant ADT was associated with improved metastasis-free survival (10-year benefit 8.0%, hazard ratio [HR], 0.65; 95% CI, 0.54 to 0.79; P < .0001), DM (subdistribution HR, 0.52; 95% CI, 0.33 to 0.82; P = .0046), prostate cancer-specific mortality (subdistribution HR, 0.30; 95% CI, 0.16 to 0.54; P < .0001), and OS (HR, 0.69; 95% CI, 0.57 to 0.83; P = .0001). However, in patients receiving WPRT (n = 3,049), no significant difference in any end point was observed in regard to ADT sequencing except for worse DM (HR, 1.57; 95% CI, 1.20 to 2.05; P = .0009) with concurrent/adjuvant ADT.

CONCLUSION

ADT sequencing exhibits a significant impact on clinical outcomes with a significant interaction with field size. Concurrent/adjuvant ADT should be the standard of care where short-term ADT is indicated in combination with PORT.

Adjuvant Radiotherapy for Upper Tract Urothelial Carcinoma: Systematic Review and Meta-Analysis

PURPOSE

Upper tract urothelial carcinoma (UTUC) is a rare form of malignancy comprising only 5% of urothelial cancers. The mainstay of treatment is radical nephroureterectomy (RNU) with bladder cuff excision. Neoadjuvant or adjuvant chemotherapy is often used in locally advanced disease. The role of adjuvant radiotherapy (RT), however, remains controversial. To further explore the potential role of adjuvant RT, we performed a systematic review and meta-analysis of the literature from 1990 to present.

METHODS AND MATERIALS

We identified 810 candidate articles from database searches, of which 67 studies underwent full-text review, with final inclusion of 20 eligible studies. Among the included studies, there were no randomized controlled trials and a single prospective trial, with the remainder being retrospective series. We performed quantitative synthesis of the results by calculating the pooled odds ratios (OR) for the primary outcome of locoregional recurrence (LRR) and secondary outcomes of overall survival (OS), cancer-specific survival (CSS) and distant recurrence (DR).

RESULTS

Adjuvant RT, which was mostly prescribed for locally advanced or margin-positive disease following RNU, significantly reduced locoregional recurrence risk OR 0.43 (95% CI: 0.23-0.70), and the effect remained significant even following subgroup analysis to account for adjuvant systemic therapy. The effect of adjuvant RT on 3-year OS, 5-year CSS and DR was non-significant. However, 5-year OS was unfavourable in the adjuvant RT arm, but study heterogeneity was high, and analysis of small-study effects and subgroups suggested bias in reporting of outcomes.

CONCLUSIONS

Adjuvant RT in the setting of locally advanced UTUC improves locoregional control following definitive surgery, but does not appear to improve OS. Higher-quality studies, ideally randomized controlled trials, are needed to further quantify its benefit in this setting, and to explore multi-modal treatments that include systemic agents given concomitantly or sequentially with RT, which may offer an OS benefit in addition to the locoregional control benefit of RT.

Local Failure Events in Prostate Cancer Treated with Radiotherapy: A Pooled Analysis of 18 Randomized Trials from the Meta-analysis of Randomized Trials in Cancer of the Prostate Consortium (LEVIATHAN)

CONTEXT

The prognostic importance of local failure after definitive radiotherapy (RT) in National Comprehensive Cancer Network intermediate- and high-risk prostate cancer (PCa) patients remains unclear.

OBJECTIVE

To evaluate the prognostic impact of local failure and the kinetics of distant metastasis following RT.

EVIDENCE ACQUISITION

A pooled analysis was performed on individual patient data of 12 533 PCa (6288 high-risk and 6245 intermediate-risk) patients enrolled in 18 randomized trials (conducted between 1985 and 2015) within the Meta-analysis of Randomized Trials in Cancer of the Prostate Consortium. Multivariable Cox proportional hazard (PH) models were developed to evaluate the relationship between overall survival (OS), PCa-specific survival (PCSS), distant metastasis-free survival (DMFS), and local failure as a time-dependent covariate. Markov PH models were developed to evaluate the impact of specific transition states.

EVIDENCE SYNTHESIS

The median follow-up was 11 yr. There were 795 (13%) local failure events and 1288 (21%) distant metastases for high-risk patients and 449 (7.2%) and 451 (7.2%) for intermediate-risk patients, respectively. For both groups, 81% of distant metastases developed from a clinically relapse-free state (cRF state). Local failure was significantly associated with OS (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.06-1.30), PCSS (HR 2.02, 95% CI 1.75-2.33), and DMFS (HR 1.94, 95% CI 1.75-2.15, p < 0.01 for all) in high-risk patients. Local failure was also significantly associated with DMFS (HR 1.57, 95% CI 1.36-1.81) but not with OS in intermediate-risk patients. Patients without local failure had a significantly lower HR of transitioning to a PCa-specific death state than those who had local failure (HR 0.32, 95% CI 0.21-0.50, p < 0.001). At later time points, more distant metastases emerged after a local failure event for both groups.

CONCLUSIONS

Local failure is an independent prognosticator of OS, PCSS, and DMFS in high-risk and of DMFS in intermediate-risk PCa. Distant metastasis predominantly developed from the cRF state, underscoring the importance of addressing occult microscopic disease. However a "second wave" of distant metastases occurs subsequent to local failure events, and optimization of local control may reduce the risk of distant metastasis.

PATIENT SUMMARY

Among men receiving definitive radiation therapy for high- and intermediate-risk prostate cancer, about 10% experience local recurrence, and they are at significantly increased risks of further disease progression. About 80% of patients who develop distant metastasis do not have a detectable local recurrence preceding it.

Addition of Docetaxel to Androgen Receptor Axis-targeted Therapy and Androgen Deprivation Therapy in Metastatic Hormone-sensitive Prostate Cancer: A Network Meta-analysis

CONTEXT

Randomized controlled trials (RCTs) have shown that addition of docetaxel or androgen receptor axis-targeted therapy (ARAT) to androgen deprivation therapy (ADT) or addition of ARAT to ADT and docetaxel improves overall survival (OS) in metastatic hormone-sensitive prostate cancer (mHSPC). However, it is unknown whether docetaxel, when given as part of triplet therapy, has an independent OS benefit.

OBJECTIVE

To compare the efficacy of ADT plus ARAT with the triplet of ADT, ARAT, and docetaxel through a network meta-analysis (NMA) of RCTs in mHSPC.

EVIDENCE ACQUISITION

Bibliographic databases and conference proceedings were searched in March 2022 for RCTs that evaluated the addition of docetaxel, ARAT, or both to ADT in mHSPC. The primary endpoint was OS. Standard random-effect NMA and Bayesian analyses were performed to compare ADT plus ARAT with triplet therapy.

EVIDENCE SYNTHESIS

Eleven RCTs (n = 11 546) were eligible. Compared with ADT plus ARAT, the triplet had a nonsignificant OS benefit (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.68-1.16), while ADT plus docetaxel (HR 1.16 [0.94-1.43]) and ADT alone (HR 1.46 [1.30-1.64]) had an increased risk of death. By P-score ordering, the triplet was the most effective treatment strategy (P score = 0.936) followed by ADT plus ARAT (P score = 0.704). The triplet had a 77% likelihood of being the best treatment strategy compared with a 23% likelihood for ADT plus ARAT.

CONCLUSIONS

The triplet of ADT, ARAT, and docetaxel was the highest ranked treatment strategy, but it did not confer a statistically significant OS benefit over ADT plus ARAT. This NMA provides the highest-level comparative evidence for these treatment approaches in the initial management of mHSPC.

PATIENT SUMMARY

We synthesized the available evidence from clinical trials conducted in newly diagnosed metastatic prostate cancer to compare the survival of patients receiving triplet therapy (androgen receptor axis-targeted therapy [ARAT], androgen deprivation therapy [ADT], and docetaxel) with those receiving only ARAT and ADT. We conclude that the triplet is a somewhat more effective treatment approach.

Methodological Comparison of Mapping the Expanded Prostate Cancer Index Composite to EuroQoL-5D-3L Using Cross-Sectional and Longitudinal Data: Secondary Analysis of NRG/RTOG 0415

PURPOSE

To compare the predictive ability of mapping algorithms derived using cross-sectional and longitudinal data.

METHODS

This methodological assessment used data from a randomized controlled noninferiority trial of patients with low-risk prostate cancer, conducted by NRG Oncology (ClinicalTrials.gov identifier: NCT00331773), which examined the efficacy of conventional schedule versus hypofractionated radiation therapy (three-dimensional conformal external beam radiation therapy/IMRT). Health-related quality-of-life data were collected using the Expanded Prostate Cancer Index Composite (EPIC), and health utilities were obtained using EuroQOL-5D-3L (EQ-5D) at baseline and 6, 12, 24, and 60 months postintervention. Mapping algorithms were estimated using ordinary least squares regression models through five-fold cross-validation in baseline cross-sectional data and combined longitudinal data from all assessment periods; random effects specifications were also estimated in longitudinal data. Predictive performance was compared using root mean square error. Longitudinal predictive ability of models obtained using baseline data was examined using mean absolute differences in the reported and predicted utilities.

RESULTS

A total of 267 (and 199) patients in the estimation sample had complete EQ-5D and EPIC domain (and subdomain) data at baseline and at all subsequent assessments. Ordinary least squares models using combined data showed better predictive ability (lowest root mean square error) in the validation phase for algorithms with EPIC domain/subdomain data alone, whereas models using baseline data outperformed other specifications in the validation phase when patient covariates were also modeled. The mean absolute differences were lower for models using EPIC subdomain data compared with EPIC domain data and generally decreased as the time of assessment increased.

CONCLUSION

Overall, mapping algorithms obtained using baseline cross-sectional data showed the best predictive performance. Furthermore, these models demonstrated satisfactory longitudinal predictive ability.

Patterns of care for non‐metastatic castration‐resistant prostate cancer: A population‐based study

Objectives

To describe patterns of practice of PSA testing and imaging for Ontario men receiving continuous ADT for the treatment of non‐metastatic castration‐resistant prostate cancer (nmCRPC).

Patients and Methods

This was a retrospective, longitudinal, population‐based study of administrative health data from 2008 to 2019. Men 65 years and older receiving continuous androgen deprivation therapy (ADT) with documented CRPC were included. An administrative proxy definition was applied to capture patients with nmCRPC and excluded those with metastatic disease. Patients were indexed upon progression to CRPC and were followed until death or end of study period to assess frequency of monitoring with PSA tests and conventional imaging. A 2‐year look‐back window was used to assess patterns of care leading up to CRPC as well as baseline covariates.

Results

At a median follow‐up of 40.1 months, 944 patients with nmCRPC were identified. Their median time from initiation of continuous ADT to CRPC was 26.0 months. 60.7% of patients had their PSA measured twice or fewer in the year prior to index, and 70.7% patients did not receive any imaging in the year following progression to CRPC. Throughout the study period, 921/944 (97.6%) patients with CRPC progressed to high‐risk (HR‐CRPC) with PSA doubling time ≤ 10 months, of which more than half received fewer than three PSA tests in the year prior to developing HR‐CRPC, and 30.9% received no imaging in the subsequent year.

Conclusion

PSA testing and imaging studies are underutilized in a real‐world setting for the management of nmCRPC, including those at high risk of developing metastatic disease. Infrequent monitoring impedes proper risk stratification, disease staging and detection of treatment failure and/or metastases, thereby delaying the necessary treatment intensification with life‐prolonging therapies. Adherence to guideline recommendations and the importance of timely staging should be reinforced to optimize patient outcomes.

Uptake and Short-Term Retention in HIV Treatment Among Men in South Africa: The Coach Mpilo Pilot Project

In this pilot project, providing peer support to men living with HIV retained a high proportion of men living with HIV in the early stages of HIV treatment and successfully supported men in returning to care after a treatment interruption.

Introduction:

Gender disparities persist across the HIV care continuum in sub-Saharan Africa. Men are tested, linked, and retained at lower rates than women. Men experience more treatment interruptions, resulting in higher rates of virological failure and increased mortality. Peer support is an approach to improving men’s engagement and retention in HIV treatment. We assessed uptake and early retention in HIV care among men in the ‘Coach Mpilo’ peer support pilot project in South Africa.

Methods:

We conducted a pilot project from March 2020 to September 2020 in 3 districts: Ehlanzeni and Gert Sibande (Mpumalanga) and Ugu (KwaZulu-Natal). Men living with HIV were invited to receive one-on-one coaching from a peer supporter who was stable on treatment. We analyzed participants’ self-reported data on demographics, uptake, and retention in HIV treatment. We described baseline characteristics using summary statistics and reported uptake and early retention proportions overall and by testing history (newly and previously diagnosed).

Results:

Among 4,182 men living with HIV, most were previously diagnosed (n=2,461, 64%) and uptake was high (92%, n=3,848). Short-term retention was 80% (n=1,979) among men previously diagnosed and 88% (n=1,213) among newly diagnosed. In September 2020, 95% (n=3,653/3,848) of all participants reported being active on HIV treatment, including those retained consistently and those who had interrupted and returned to care. Among participants experiencing treatment interruption after enrolling, the majority (82%, n=464) returned to treatment, largely within 2 months.

Conclusions:

Improving linkage to and retention in HIV treatment among men is essential for their health and for treatment as prevention. This pilot project provided preliminary evidence that a peer-led support model was acceptable, retained a high proportion of men in the early stages of ART, and supported men returning to care after treatment interruption. These promising results require further investigation to assess impact, scalability, and cost-effectiveness.

Real-world management of metastatic castration-resistant prostate cancer (mCRPC): A national multicenter cohort study

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Background: The management of patients with mCRPC has evolved since the introduction of androgen-receptor axis targeted agents (ARATs). The Genitourinary Research Consortium (GURC) initiated a prospective, phase 4, multicentre, non-interventional, longitudinal cohort study of Canadian men with advanced prostate cancer to determine real-world treatment patterns and outcomes. Methods: 25 sites across Canada participated in this study including patients managed by urologists, medical- and radiation-oncologists between 2018 to 2021. Baseline patient characteristics and mCRPC treatment patterns are reported here. Treatment patterns reviewed included time to second-line treatment use and time to progression or death. Results: 136 mCRPC patients were enrolled. Median age was 73 years (range 66 to 80) with 54 (40%) having a Gleason score of >8 at diagnosis. Median PSA at enrollment was 8.9 (2.4 to 25.1) ng/ml. At study entry, 90/132 (66%) patients with mCSPC and 42/132 (31%) patients nmCRPC had progressed to develop mCRPC. One hundred and twenty-one (89%) of patients in this cohort received first-line treatment for mCRPC, the most common was abiraterone acetate + prednisone in 67 (49%) and enzalutamide in 41 (30%), followed by docetaxel in 6 (4.4%), and Radium-223 in 5 (3.7%) patients. During the 25-month median follow-up period (range 6-28), 59 (49%) of the patients receiving first line mCRPC therapy had documented disease progression or death. At the time of last recorded follow-up, 37 (28%) patients who progressed received a second-line therapy for mCRPC. Median time to progression in this cohort was 21 months (95% CI: 15.2 - NE), with ARAT-to-ARAT being the most common sequencing pattern observed in 15 (39%) patients, followed by ARAT to chemotherapy in 14 (37%). Conclusions: In this real-world analysis of mCRPC patients, ARAT therapy was the preferred approach for first-line treatment intensification in over 108 (80%) patients. Despite evidence of poor response rates, ARAT-to-ARAT was the most common sequencing for second line therapy, followed by ARAT-to-chemotherapy treatment. Further analysis and follow-up will help define optimal mCRPC management, in real world setting.

Local failure, distant metastasis, and survival after definitive radiotherapy for intermediate- and high-risk prostate cancer: An individual patient-level meta-analysis of 18 randomized trials

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Background: The prognostic importance of local failure (LF) after definitive radiotherapy (RT) in patients with NCCN intermediate- (IRPCa) and high-risk prostate cancer (HRPCa) remains unclear, particularly given the likelihood that occult distant metastases (DMs) at presentation may be the true driver of natural history. Here, we leverage individual patient data (IPD) from 18 randomized control trials (RCTs) to evaluate the prognostic impact of LF and the kinetics of DM after RT. Methods: IPD for 18 RCTs were obtained from the Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) Consortium, comprising a total of 12533 patients (6288 HRPCa & 6245 IRPCa). Multivariable Cox proportional hazards (PH) models were developed to evaluate the relationship between overall survival (OS), PCa-specific survival (PCSS), DM-free survival (DMFS) & LF as a time-dependent covariate, adjusted for clinicodemographic parameters. Markov PH models, defined via transitions between 4 states, were developed to evaluate the aforementioned relationship. Proportional hazards assumption was imposed and examined for both models. Time is from randomization. Results: Median follow-up was 9.1 years. There were 795 (13%) LF & 1288 (21%) DM events for patients with HRPCa; these numbers were 449 (7%) & 451 (7%) for IRPCa. For HRPCa & IRPCa, 81% and 81% of DMs developed from a clinically relapse-free state (cRFS), with a median time of 46 and 60 months, respectively (p < 0.0001). 39% & 13% of DM events occurred within 2 years after RT for HRPCa & IRPCa, respectively. At later time points, DM events were more likely to emerge after an LF event for both HRPCa (9% vs. 34% between 0-2 vs. 8-10 years post-RT, p = 0.001) and IRPCa (10% vs. 34% between 0-2 vs. 8-10 years post-RT, p = 0.008). LF was significantly associated with OS (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.06–1.30), PCSS (HR 2.02, 95% CI 1.75-2.33) & DMFS (HR 1.94, 95% CI 1.75–2.15) (p < 0.01 for all) in patients with HRPCa. LF was also significantly associated with DMFS (HR 1.57, 95% CI 1.36–1.81) but not OS in patients with IRPCa. Patients who had not transitioned to the LF state had a significantly lower HR of transitioning to a PCa-specific death state than those who transitioned to the LF state (HR 0.32, 95% CI 0.21–0.50, p < 0.001). Conclusions: LF is an independent prognosticator of OS, PCSS & DMFS in HRPCa and of DMFS in IRPCa. The predominant mode of DM development is from the cRFS state, underscoring the importance of accurate upfront staging & systemic therapy. However, particularly at late time points, an increasing proportion of DM events originated after diagnosis of a LF, constituting a “second wave” of DM events. This suggests that optimizing local control is also important, though the majority of DM events appear prior to a clinically-detected LF.

Patterns of care for patients with non-metastatic castration-resistant prostate cancer: Population-based study in Ontario, Canada

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Background: To describe patterns of practice of PSA testing and imaging for Ontario men receiving continuous androgen deprivation therapy (ADT) for the treatment of non-metastatic castration-resistant prostate cancer (nmCRPC). Methods: This was a retrospective, longitudinal, population-based study of administrative health data from 2008 to 2019. Men > 65 years old receiving continuous ADT with documented CRPC were included. An administrative proxy definition was applied to capture patients with nmCRPC patients and excluded those with metastatic disease. Patients were indexed upon progression to CRPC and were followed until death or end of study period to assess frequency of monitoring with PSA tests and conventional imaging. A 2-year look-back window was used to assess patterns of care leading up to CRPC, as well as baseline covariates. Results: At a median follow-up of 40 months, 944 patients with CRPC were identified. Their median time from initiation of ADT to CRPC was 26 months, 61% of patients had their PSA measured twice or fewer in the year prior to index and 71% patients did not receive any imaging in the year following progression to CRPC. Almost all patients (98%, n = 921/944) in the study progressed to high-risk CRPC (HR-CRPC) during the study period, of which more than half received fewer than 3 PSA tests in the year prior to progression to HR-CRPC, and 31% received no imaging in the subsequent year. Conclusions: PSA testing and imaging studies are under-utilized in a real-world setting for the management of nmCRPC, including those at high-risk of developing metastatic disease. Infrequent monitoring impedes proper risk stratification, disease staging, detection of treatment failure and/or metastases, likely delaying necessary treatment intensification with life-prolonging therapies. Adherence to guideline recommendations and the importance of timely staging should be reinforced to optimize patients’ outcome.

Cannabidiol and refractory epilepsy: parental and caregiver perspectives of participation in a compassionate access scheme

Background

The Compassionate Access Scheme (CAS) being delivered through the Queensland Children’s Hospital is designed to allow access to an investigational purified Cannabidiol oral solution to paediatric patients with severe refractory epilepsy. The objectives of this study were to conduct semi-structured interviews to:

1. Understand families’ expectations and attitudes about the use of an investigational cannabinoid product for their child’s seizures;

2. Understand families’ perceptions of Cannabidiol’s efficacy for their child’s seizures; and other aspects of their child’s behaviour, quality of life and/or cognition.

Methods

Children aged 2-18 years had been enrolled in, or were enrolled in a compassionate access scheme for Cannabidiol at the time of the study. Semi-structured interviews (n = 19) with parents or caregivers (n = 23) of children diagnosed with refractory epilepsy were voice-recorded, transcribed and analysed to generate common themes.

Results

Key themes emerged relating to seizure activity, family and school engagement, drug safety and legal access, efficacy, clinical support, social acceptance of the medication and program delivery. The use of Cannabidiol was perceived to have benefits in relation to reducing the severity and frequency of seizure activity for almost a third of patients experiencing refractory epilepsy. Participants described other benefits including improved social engagement, wakefulness and a reduction of side effects related to a reduction of conventional medication dosage.

Conclusion

This study provided unique perspectives of families’ experiences managing untreatable epilepsy, their experiences with conventional and experimental pharmacological treatments and health services. Whilst families’ perceptions showed the use of Cannabidiol did not provide a therapeutic reduction in the seizure activity for all patients diagnosed with refractory epilepsy, it’s use as an additional pharmacological agent was perceived to provide other benefits by some patient families.

Treatment of Trigeminal Neuralgia With Stereotactic Radiosurgery Improved Symptoms of Morbihan Syndrome

Trigeminal neuralgia (TN) is a neuropathic pain disorder characterized by paroxysmal pain in the maxillary and mandibular regions of the face. Morbihan syndrome is a disease that classically presents with dermatologic findings, including progressive facial edema and erythema. There are no previous reports of the onset of trigeminal neuralgia with Morbihan syndrome or previous reports describing improvement in symptoms of Morbihan syndrome with treatment of trigeminal neuralgia. We describe the case of a 62-year-old female who presented with trigeminal neuralgia and shortly thereafter developed significant facial edema and was diagnosed with Morbihan syndrome. The neuralgia was refractory to medical management and was effectively treated with stereotactic radiosurgery (SRS). This coincided with an improvement in her Morbihan syndrome that is now controlled following stereotactic radiosurgery and continued lymphatic massage.

Real-World Use of Androgen-Deprivation Therapy: Intensification Among Older Canadian Men With de Novo Metastatic Prostate Cancer

BACKGROUND

Despite the wealth of evidence demonstrating the efficacy of treatment intensification beyond androgen-deprivation therapy (ADT) among patients with de novo metastatic castration-sensitive prostate cancer (mCSPC), little is known of its real-world use. This study examined the real-world uptake of ADT treatment intensification among older men in a large Canadian province.

METHODS

We performed a retrospective population-based cohort study using province-wide linked administrative data in Ontario, Canada. Patients 66 years of age and older with de novo mCSPC were included and their treatment with conventional ADT-based regimens, ADT plus next-generation androgen receptor axis-targeted therapy, and ADT plus docetaxel were identified and stratified by time.

RESULTS

From 2014 to 2019, 3556 patients were identified with de novo mCSPC. Most patients (n = 2794 [78.6%]) were treated with a conventional ADT regimen, whereas 399 (11.2%) patients received ADT intensification with docetaxel and 52 (1.5%) patients received abiraterone acetate plus prednisone. In a time-stratified analysis of ADT intensification before and after the pivotal AA+P trial (LATITUDE), AA+P uptake increased from 0.5% to 3.0%, whereas docetaxel use dropped from 12.0% to 10.0%. The median survival of the study population was 18 months (interquartile range = 10-31).

CONCLUSIONS

The majority of patients with de novo mCSPC are treated with ADT alone in the Canadian real-world setting, despite randomized clinical trial evidence of benefit with the use of ADT-intensified regimens. As ADT treatment intensification is substantially underused, better understanding of the barriers to treatment and targeted education to address them are needed.

Quality Assurance of Radiotherapy During the Covid-19 Pandemic: Impact on Peer Review in 14 Regional Cancer Centers Across Ontario

Purpose/Objective(s)

Quality Assurance (QA) is an integral part of the delivery of Radiotherapy (RT). Peer review (PR) is an essential component of the QA process mandated by Cancer Care Ontario (CCO). The COVID-19 pandemic has caused significant disruptions to cancer care worldwide. We aimed to investigate PR rates across all regional cancer centers in Ontario during the pandemic.

Materials/Methods

Using a provincial database maintained by CCO, PR data regarding completed curative and palliative RT courses were reviewed from December 2014 to November 2020. Peer reviews reported completed in March 2020 onward were considered to be completed during the pandemic. The monthly PR rates of 2019 were used as a baseline comparator. Wilcoxon signed-rank test (two-tailed) was used to determine significance in PR rates and courses of RT delivered. A P-value of < 0.05 was considered significant.

Results

A total of 24,936 radical courses and 18,759 palliative radiotherapy courses were completed in Ontario during the first 8 months of the pandemic. We found no difference in the average number of RT courses the year prior compared to during the pandemic for radical (3117/month vs 3382/month, P = 0.078) or palliative courses (2344/month vs 2227/month, P = 0.195). PR rates of radical RT were significantly decreased compared to the previous 12-month time period 86.1% vs 88.5% (95% CI: 0.6%-4.6% P = 0.014). Palliative RT also had a decrease in PR from 61.7% to 56.6% (95% CI:1.4%-7.2%, P = 0.016). In the 2 immediate months following March 2020, there was a decrease of PR rates with radical RT PR rates nadiring at 83% and palliative RT nadiring a 53% PR rate, the lowest since April 2016 and January 2018 respectively. This trend quickly reversed and PR rates increased in subsequent months. Analysis by disease site indicated a significant decrease compared to the prior year in disease site-specific PR rates for radical courses within breast (87.8% vs 90.3%, P = 0.16) and gynecologic (76.9% vs 84.1%, P = 0.049) disease sites respectively. Lung, Head and Neck, Gastrointestinal and CNS sites had no significant differences in PR rates when compared to the preceding year.

Conclusion

Peer review rates had an initial decrease across regional cancer in both radical and palliative intent radiation. Overall, peer review rates remain modestly lower than the period immediately preceding the pandemic. All centers still maintained a high rate of PR during the initial 8 months of the COVID 19 pandemic.