DASL-HiCaP: A randomized, phase 3, double-blind trial of darolutamide with androgen-deprivation therapy and definitive or salvage radiation for localized very high-risk prostate cancer

TPS396

Background: Radiation therapy (RT), plus androgen deprivation therapy (ADT) with a luteinizing hormone releasing hormone analogue (LHRHA), is a standard of care for patients with very high-risk localized prostate cancer (PC), or with very high-risk features and persistent PSA after radical prostatectomy (RP). Despite this, incurable distant metastases develop within 5 years in 15% of patients with very high-risk features. Darolutamide is a structurally distinct oral androgen receptor antagonist with low blood-brain-barrier penetration, a demonstrated favorable safety profile, and low potential for drug-drug interactions. Our aim is to determine the efficacy of adding darolutamide to ADT and RT used either as primary definitive therapy, or as salvage therapy, for very high-risk PC. Methods: This study is a randomized (1:1), phase 3, placebo-controlled, double-blind, international trial for patients planned for RT who have very high-risk localized PC on conventional imaging; or very high-risk features with PSA persistence or rise within one year following RP. The trial is stratified by previous RP; planned use of adjuvant docetaxel; clinical or pathological pelvic nodal involvement. 1100 participants will be randomized to receive darolutamide 600 mg or placebo twice daily for 96 weeks in combination with SOC (LHRHA for 96 weeks, plus RT starting week 8-24 from randomization). Participants are allowed nonsteroidal antiandrogen in addition to LHRHA for up to 90 days prior to randomization. Early treatment with up to 6 cycles of docetaxel completed at least 4 weeks prior to RT is permitted. The primary endpoint is metastasis-free survival, with secondary endpoints of overall survival, PC-specific survival, PSA-progression free survival, time to subsequent hormonal therapy, time to castration-resistance, frequency and severity of adverse events, health related quality of life, fear of recurrence. Tertiary endpoints include incremental cost-effectiveness, and identification of prognostic and/or predictive biomarkers of treatment response, safety, and resistance to study treatment. Clinical trial information: NCT04136353 .

Early Gamma Knife stereotactic radiosurgery to the tumor bed of resected brain metastasis for improved local control

OBJECT

Optimal case management after surgical removal of brain metastasis remains controversial. Although postoperative whole-brain radiation therapy (WBRT) has been shown to prevent local recurrence and decrease deaths, this modality can substantially decrease neurocognitive function and quality of life. Stereotactic radiosurgery (SRS) can theoretically achieve the same level of local control with fewer side effects, although studies conclusively demonstrating such outcomes are lacking. To assess the effectiveness and safety profile of tumor bed SRS after resection of brain metastasis, the authors performed a retrospective analysis of 110 patients who had received such treatment at the Centre Hospitalier Universitaire de Sherbrooke. They designed the study to identify risk factors for local recurrence and placed special emphasis on factors that could potentially be addressed.

METHODS

Patients who had received treatment from 2004 through 2013 were included if they had undergone surgical removal of 1 or more brain metastases and if the tumor bed was treated by SRS regardless of the extent of resection or prior WBRT. All cases were retrospectively analyzed for patient and tumor-specific factors, treatment protocol, adverse outcomes, cavity outcomes, and survival for as long as follow-up was available. Univariate and multivariate Cox regression analyses were performed to identify risk factors for local recurrence and predictors of increased survival times.

RESULTS

Median patient age at first SRS treatment was 58 years (range 37-84 years). The most frequently diagnosed primary tumor was non-small cell lung cancer. The rate of gross-total resection was 81%. The median Karnofsky Performance Scale score was 90%. Tumor bed SRS was performed at a median of 3 weeks after surgery. Median follow-up and survival times were 10 and 11 months, respectively. Actuarial local control of the cavity at 12 months was 73%; median time to recurrence was 6 months. According to multivariate analysis, risk factors for recurrence were a longer surgery-to-SRS delay (HR 1.625, p = 0.003) and a lower maximum radiation dose delivered to the cavity (HR 0.817, p = 0.006). Factors not associated with increased recurrence were subtotal or piecemeal resections, prior WBRT, histology of the primary tumor, and larger cavity volume. No factors predictive of survival were identified. Symptomatic radiation-induced enhancement occurred in 6% of patients and leptomeningeal dissemination in 11%. Pathologically confirmed radiation-induced necrosis occurred in 1 (0.9%) patient.

CONCLUSIONS

Adjuvant tumor bed SRS after the resection of brain metastasis is a valuable alternative to adjuvant WBRT. Risk factors for local recurrence are lower maximum radiation dose and a surgery-to-SRS delay longer than 3 weeks. Outcomes were not worse for patients who had undergone prior WBRT and subtotal or piecemeal resections. Pending the results of prospective randomized controlled trials, the authors' study supports the safety and efficacy of adjuvant SRS after resection of brain metastasis. SRS should be performed as early as possible, ideally within 3 weeks of the surgery.

The Efficacy and Sequencing of a Short Course of Androgen Suppression on Freedom From Biochemical Failure When Administered With Radiation Therapy for T2-T3 Prostate Cancer

PURPOSE

We evaluated the benefits and sequencing of androgen suppression (AS) administered with external beam radiation therapy (EBRT) in T2-T3 prostate cancers.

MATERIALS AND METHODS

Between 1990 and 1999, 481 patients were entered in 2 successive, prospective, randomized studies, including 161 in the study 1 and 325 in study 2. Eligible patients had clinical stages T2-T3 prostate cancer. In the first study (L-101) subjects were randomly allocated among EBRT alone (group 1), EBRT preceded by 3 months of AS (group 2), and neoadjuvant, concomitant and adjuvant AS for a total of 10 months (group 3). In the second study (L-200) we analyzed neoadjuvant and concomitant AS (total 5 months) vs neoadjuvant, concomitant and short course adjuvant (total 10 months) AS with EBRT. In each study we used a total AS (a luteinizing hormone-releasing hormone agonist plus an antiandrogen) and a standard dose of radiation therapy at that time. Patient characteristics were well balanced in regard to age, stage, prostate specific antigen and Gleason score. No biochemical evidence of disease (BNED) was defined as an end point according to the Vancouver rule.

RESULTS

In the study 1 at a median followup of 5 years 7-year biochemical-free survival rates were 42%, 66% and 69% in groups 1 to 3, respectively. BNED was significantly different between groups 1 and 2 (p = 0.009) and between groups 1 and 3 (p = 0.003) but not between groups 2 and 3 (p = 0.6). Multivariate analysis using a Cox proportional hazards model showed an HR of 6.1 for Gleason score (p = 0.001), 1.4 for PSA (p = 0.002), 0.5 for group 1 vs group 2 (p = 0.01) and 0.35 for group 1 vs group 3 (p = 0.008). In study 2 BNED at 4 years was 65%. There was no significant difference between arms 1 and 2 (p = 0.55).

CONCLUSIONS

The analysis of study 1 shows a benefit of using a short course of neoadjuvant AS with EBRT vs EBRT alone for localized T2-T3 prostate cancers. Moreover, in each study adding a short course of adjuvant AS after neoadjuvant 1 provided no more advantage in these patients.