Long-Term Outcomes of NRG/RTOG 0126, a Randomized Trial of High Dose (79.2 Gy) vs. Standard Dose (70.2 Gy) Radiation Therapy (RT) for Men with Localized Prostate Cancer

PURPOSE/OBJECTIVE(S)

NRG/RTOG 0126, a phase III trial for men with localized prostate cancer testing whether dose escalation to 79.2 Gy with 3DCRT/IMRT improved overall survival (OS). Long-term results of this trial are presented.

MATERIALS/METHODS

Patients with clinical stage T1b-T2b and either Gleason Score (GS) 2-6 and 10 ≤ PSA < 20 or GS 7 and PSA < 15 were eligible and randomized to receive 79.2 Gy or 70.2 Gy. No previous or concurrent androgen withdrawal therapy was administered. Treatment was delivered with 3DCRT/IMRT to a dose of 79.2 Gy in 44 fractions or 70.2 Gy in 39 fractions to the PTV encompassing the prostate and seminal vesicles. Image guidance was not required. ASTRO and Phoenix definitions were used for biochemical failure (ABF and PBF, respectively). OS was estimated by the Kaplan-Meier method and arms compared with the log-rank test. ABF, PBF, local progression (LP), distant metastases (DM) and time to late GI/GU toxicities were estimated by the cumulative incidence method and arms compared with Gray's test.

RESULTS

One thousand five hundred thirty-two men were randomized, 763 to 79.2 Gy and 769 to 70.2 Gy. 1499 were eligible, 748 and 751 in the 79.2 Gy and 70.2 Gy arms respectively. Median age was 71, 70% had PSA < 10 ng/ml, 84% with GS 7, 57% had T1 disease, and 66% treated with 3D-CRT. Outcomes are shown in the TABLE: . With a median follow up of 12 years, there was no significant difference in OS. There was a statistically significant decrease in the cumulative incidence of ABF, PBF, DM, LP, and salvage therapies in the 79.2 Gy arm. There were significantly higher rates of grade 2+ GI and GU toxicity in the 79.2 Gy arm. There were no statistically significant differences in the rates of grade 3+ GU or GI toxicity between either arm.

CONCLUSION

Long term follow up confirms no improvement in OS with dose escalation in this study population. However, there are significant improvements in ABF, PBF, DM, LP, and need for salvage therapy. Despite the use of more salvage therapy in the low dose arm, dose escalated RT resulted in lower rates of DM, a clinically relevant endpoint. Patients receiving dose escalation do experience a higher rate of grade 2+ GU and GI toxicity but no worse grade 3+ toxicities.

Prospective Characterization of Circulating Tumor Cells in Hormone Sensitive Oligometastatic Prostate Cancer Patients on a Metastasis-Directed Therapy Trial

PURPOSE/OBJECTIVE(S)

Prospective data have shown that metastasis-directed therapy (MDT) can alter the natural history of oligometastatic disease. In hormone-sensitive prostate cancer (HSPC), the clinical effect of MDT has been validated by STOMP, ORIOLE and SABR-COMET phase II trials. Circulating tumor cells (CTCs) are likely the source for the formation of macroscopic metastases. CTCs may provide an approach for identifying subgroups of patients with oligometastatic HSPC (oligoHSPC) that would benefit most from MDT. Our main goal was to evaluate the feasibility of CTC detection and subtypes in oligoHSPC patients that may benefit from MDT.

MATERIALS/METHODS

ORIOLE randomized men with recurrent HSPC with 1-3 metastases to observation (Obs) vs. stereotactic ablative radiotherapy (SABR) MDT. Blood samples were prospectively collected at baseline (D0) and 6-mos (D180) and shipped for analysis on Epic Sciences liquid biopsy platform (Epic Sciences, San Diego, CA). Machine learning algorithms identified CTCs and characterized androgen receptor (AR) and PSMA expression. Association with clinical factors and outcomes were examined. Biochemical failure-free survival (BFFS) event was a PSA rise of at least 2 ng/mL and 25% above nadir. Progression-free survival (PFS) was a composite endpoint including BFFS event, radiologic progression (RECIST v1.1); symptomatic progression; initiation of ADT; or death. Comparisons of patient and tumor characteristics performed by two-sample t-tests. Survival curves were generated by the Kaplan-Meier method and evaluated by the log-rank test. Effect of SABR on post-SABR on CTC levels were calculated by McNemar test.

RESULTS

A total of 82 samples were collected in ORIOLE: 70 SABR (35 D0 and 35 D180) and 12 Obs (7 D0 and 5 D180). 30/42 men had CTCs detected on D0 (71%; AR+ = 7, PSMA+ = 13) and in 26/40 on D180 (65%; AR+ = 9, PSMA+ = 8). Median follow-up was 41.7-mos. There was no association between CTC presence or subtypes (AR+ or PSMA+) with Gleason score or PSA. PFS was significantly lower in the patients with AR+ vs. AR- CTCs on D0 in the SABR arm (p = 0.011, median PFS: AR+ = 9.3- vs. AR+ = 27.1-mos). The median BFFS trended towards a difference for AR+ = 12.9- vs. AR- = 29.2-mos (D180, p = 0.058). SABR had no effect on the presence or subtypes of CTC at D180.

CONCLUSION

Baseline and dynamic CTC levels and their subtypes in oligoHSPC from the ORIOLE randomized trial of MDT was examined. AR+ CTCs at baseline and 6-mos were correlated with clinical outcomes following SABR. Longer follow-up, further analysis and a greater number of patients are needed for a more comprehensive conclusion.

A Precision Medicine Navigator Can Mitigate Inequities Associated with Utilization of Genomic Tests in Black Men with Prostate Cancer

PURPOSE/OBJECTIVE(S)

Black men with prostate cancer in the United States experience disproportionately worse clinical outcomes compared to other racial groups. Identifying more reliable prognosticators to address these inequities has thus been the subject of considerable research scrutiny. However, prognostic genomic tools and genomic biorepositories suffer from an even greater lack of racial diversity. Strategies to mitigate these amplifying developments in inequities are desperately needed. We hypothesized that the presence of a precision medicine navigator (PMN) may mitigate inequities with standard of care (SOC) genomic test utilization among Black men with prostate cancer.

MATERIALS/METHODS

We retrospectively reviewed prostate cancer consults within one healthcare system from 11/2/2021 to 1/2/2022. We compared the frequency of patients who received SOC Decipher or Tempus genomic testing in the 7 months prior to the PMN start (pre-PMN) to the 7 months afterward (post-PMN). Chi square analysis was used to compare subgroups. Binary logistic regression was used to calculate the odds of receiving genomic testing.

RESULTS

The sample included 693 patients, 44.9% (311/693) pre-PMN and 55.1% (382/693) post-PMN, with a median age of 68 in both groups. Pre- and post-PMN racial distributions were similar with 60.1% and 60.2% White, 35.1% and 34% Black, 3.2% and 3.7% Asian/Pacific Islander, and 1.3% and 2.1% Latino, respectively. Pre- and post-PMN NCCN risk category distribution was 15.2% and 10.4% low risk, 46.8% and 49.9% intermediate risk, and 38.1% and 39.7% high risk, respectively. Pre- and post-PMN groups had 14.5% and 17% distant metastases, 77.2% and 76.9% localized disease, 10.3% and 10% prior prostatectomy, 47% and 51% income below sample median, 51% and 52% with Medicare/Medicaid, and 47% and 48% seen at community hospitals, respectively. There were no statistically significant differences for these variables pre- and post-PMN. However, from pre- to post-PMN, the proportion of Black patients receiving genomic testing increased from 19% to 58%. Black patients seen post-PMN were six times more likely to receive testing (p<0.001). Significant increases in SOC genomic testing post-PMN also occurred among lower median income patients, patients with Medicare/Medicaid, and community hospital patients.

CONCLUSION

The presence of a PMN may improve disparate rates of Black patients receiving SOC genomic tests for prostate cancer compared to other racial groups and may alleviate genomic testing inequities among other demographics.

Multi-Institutional Experience of Proton Therapy for Rhabdomyosarcoma and Ewing Sarcoma in the Proton Collaborative Group (PCG) Prospective Registry

PURPOSE/OBJECTIVE(S)

To report on outcomes, acute toxicities, and the use of dose-escalation with proton therapy (PT) in patients with rhabdomyosarcoma and Ewing sarcoma in a prospective multi-institutional registry (PCG).

MATERIALS/METHODS

Data on patients with primary rhabdomyosarcoma and Ewing sarcoma treated with definitive PT (defined as ≥45 Gy) were queried from the PCG registry. A similar query was performed of our institutional database with IRB approval. Overall survival rates were calculated by Kaplan-Meier. Toxicities were scored using CTCAE v4.0.

RESULTS

A total of 354 patients across 10 institutions (203 rhabdomyosarcoma, 151 Ewing sarcoma) met the eligibility criteria. Median age was 9 years (Interquartile Range: 5-15). Median dose was 50.4 GyRBE for rhabdomyosarcoma patients (Range: 45-66 GyRBE) and 55.8 GyRBE for Ewing sarcoma patients (Range: 45-66 GyRBE). Median follow-up was 2.4 years (Range 0.3-12.3 years). Two-year overall survival rates were 81.1% (95% CI: 73.7%-88.5%) for rhabdomyosarcoma and 79.1% (95% CI: 71.7%-86.2%) for Ewing sarcoma. The Table lists the prescription doses delivered by tumor histology; 28.1% of rhabdomyosarcoma and 21.9% of Ewing sarcoma patients, respectively, received dose-escalated radiotherapy (defined as >50.4 Gy for rhabdomyosarcoma and >55.8 Gy for Ewing sarcoma). Excluding alopecia and skin desquamation, 153 patients (43.2%) developed any acute grade 2+ non-hematologic toxicity, while 49 patients (13.8%) developed one or more grade 3 toxicities. The most common grade 3 toxicities were anorexia/weight loss (7.3%), pain (7.3%) mucositis/esophagitis (4.8%), and nausea/vomiting (3.1%). One grade 4 toxicity (esophagitis) and no deaths were reported during treatment.

CONCLUSION

In this multi-institutional prospective registry, 28.1% of rhabdomyosarcoma and 21.9% of Ewing sarcoma patients received dose-escalated PT, with 13.8% of patients developing grade 3 toxicities. Long-term outcomes for disease control and late toxicity and anticipated cooperative group trial results are needed to fully assess the benefits and risks of dose-escalated radiotherapy for these tumors.

Multi-Institutional Experience of Proton Therapy for Osteosarcoma in the Proton Collaborative Group (PCG) Prospective Registry

PURPOSE/OBJECTIVE(S)

To report on the utilization of dose-escalated radiotherapy, acute toxicities, and survival following definitive proton therapy (PT) for osteosarcoma patients in a prospective multi-institutional study.

MATERIALS/METHODS

Data on patients with osteosarcoma treated with definitive intent PT were queried from the Proton Collaborative Group (PCG) prospective registry. A similar query was performed on an institutional database with IRB approval. Overall survival rates were calculated by Kaplan-Meier. Toxicities were scored using CTCAE v4.0.

RESULTS

Forty osteosarcoma patients across 9 institutions received definitive intent PT between 2011-2021 and met the eligibility criteria. Median age was 32 years (Range: 6-86 years). Median PT dose was 66.6 GyRBE (Range: 50.4-80.0 GyRBE); 38 patients received proton therapy alone, whereas 2 received combined proton/photon therapy. Seventeen (42.5%) patients received doses ≥70 GyRBE. Median follow-up was 3.1 years (Range: 0.9-10.5 years). One-year and three-year overall survival rates were 83.5% and 59.1%, respectively, with 14 deaths due to disease. Excluding skin desquamation and alopecia, 22 patients (55.0%) developed any acute grade 2+ toxicity, and 5 patients (12.5%) developed any grade 3 toxicities. No acute grade 4-5 toxicities were reported. The most frequent grade 2+ non-skin toxicities were fatigue (37.5%), anorexia/weight loss (17.5%), mucositis/esophagitis (22.5%), pain (20.0%), and nausea/vomiting (10.0%). The most frequent grade 3 toxicities were anorexia/weight loss (5.0%), mucositis/esophagitis (5.0%), and neurologic symptoms (5.0%).

CONCLUSION

In this multi-institutional study, 42.5% of osteosarcoma patients treated with PT received doses between 70-80 Gy, with 12.5% experiencing any grade 3 toxicity. Long-term outcomes for disease control, late toxicity, and quality-of-life are needed to more fully assess the benefits and risks of dose-escalated radiotherapy in this radioresistant tumor. The authors plan to assess the outcomes of osteosarcoma patients treated with dose-escalated radiotherapy for unresectable or gross residual disease in future studies.

Carrier-Envelope-Phase Modulated Currents in Scanning Tunneling Microscopy

Carrier-envelope-phase (CEP) stable optical pulses combined with state-of-the-art scanning tunneling microscopy (STM) can track and control ultrafast electronic tunneling currents. On the basis of nonequilibrium Green's function formalism, we present a time and frequency domain theoretical study of CEP-stable pulse-induced tunneling currents between an STM tip and a metal substrate. It is revealed that the experimentally observed phase shift between the maximum tunneling current and maximum electric field is caused by the third-order response to the electric field. The shift is also found to be sensitive to the duration of pulses. The tunneling process can thus be precisely manipulated by varying the phase and duration of these pulses.

STM Imaging of Electron Migration in Real Space and Time: A Simulation Study

Using a simulation protocol that mimics ultrafast scanning tunneling microscopy (STM) experiments, we demonstrate how pump-probe ultrafast STM may be used to image electron migration in molecules. Two pulses are applied to a model system, and the time-integrated current through the tip is calculated versus the delay time and tip position to generate STM images. With suitable pump and probe parameters, the images can track charge migration with atomistic spatial and femtosecond temporal resolutions.

Time-Dependent Density Functional Theory for Open Systems and Its Applications

Photovoltaic devices, electrochemical cells, catalysis processes, light emitting diodes, scanning tunneling microscopes, molecular electronics, and related devices have one thing in common: open quantum systems where energy and matter are not conserved. Traditionally quantum chemistry is confined to isolated and closed systems, while quantum dissipation theory studies open quantum systems. The key quantity in quantum dissipation theory is the reduced system density matrix. As the reduced system density matrix is an O(M! × M!) matrix, where M is the number of the particles of the system of interest, quantum dissipation theory can only be employed to simulate systems of a few particles or degrees of freedom. It is thus important to combine quantum chemistry and quantum dissipation theory so that realistic open quantum systems can be simulated from first-principles. We have developed a first-principles method to simulate the dynamics of open electronic systems, the time-dependent density functional theory for open systems (TDDFT-OS). Instead of the reduced system density matrix, the key quantity is the reduced single-electron density matrix, which is an N × N matrix where N is the number of the atomic bases of the system of interest. As the dimension of the key quantity is drastically reduced, the TDDFT-OS can thus be used to simulate the dynamics of realistic open electronic systems and efficient numerical algorithms have been developed. As an application, we apply the method to study how quantum interference develops in a molecular transistor in time domain. We include electron-phonon interaction in our simulation and show that quantum interference in the given system is robust against nuclear vibration not only in the steady state but also in the transient dynamics. As another application, by combining TDDFT-OS with Ehrenfest dynamics, we study current-induced dissociation of water molecules under scanning tunneling microscopy and follow its time dependent dynamics. Given the rapid development in ultrafast experiments with atomic resolution in recent years, time dependent simulation of open electronic systems will be useful to gain insight and understanding of such experiments. This Account will mainly focus on the practical aspects of the TDDFT-OS method, describing the numerical implementation and demonstrating the method with applications.

Can Molecular Quantum Interference Effect Transistors Survive Vibration?

Quantum interference in cross-conjugated molecules can be utilized to construct molecular quantum interference effect transistors. However, whether its application can be achieved depends on the survivability of the quantum interference under real conditions such as nuclear vibration. We use two simulation methods to investigate the effects of nuclear vibration on quantum interference in a meta-linked benzene system. The simulation results suggest that the quantum interference is robust against nuclear vibration not only in the steady state but also in its transient dynamics, and thus the molecular quantum interference effect transistors can be realized.

Time-dependent density functional theory for open systems with a positivity-preserving decomposition scheme for environment spectral functions

Understanding electronic dynamics on material surfaces is fundamentally important for applications including nanoelectronics, inhomogeneous catalysis, and photovoltaics. Practical approaches based on time-dependent density functional theory for open systems have been developed to characterize the dissipative dynamics of electrons in bulk materials. The accuracy and reliability of such approaches depend critically on how the electronic structure and memory effects of surrounding material environment are accounted for. In this work, we develop a novel squared-Lorentzian decomposition scheme, which preserves the positive semi-definiteness of the environment spectral matrix. The resulting electronic dynamics is guaranteed to be both accurate and convergent even in the long-time limit. The long-time stability of electronic dynamics simulation is thus greatly improved within the current decomposition scheme. The validity and usefulness of our new approach are exemplified via two prototypical model systems: quasi-one-dimensional atomic chains and two-dimensional bilayer graphene.

Weekly paclitaxel (P) with concurrent external beam radiation (EBRT) and androgen deprivation therapy (ADT) in high-risk prostate cancer (PC) patients with or without prior prostatectomy (RP)

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Background: EBRT with ADT (4 mos to 2–3 yrs) is standard treatment for high risk PC. In this trial, we evaluated weekly P given concurrently with EBRT and ADT in high risk PC. Methods: For pts undergoing RP, high risk was defined as: pT3 and/or pN+, M0, and/or rising PSA (> 0.5) post RP. For pts not undergoing RP (i.e. locally advanced PC [LAPC]) high risk included: cT2b-4N0, N+, M0; bGS 8–10; bGS ≥ 7 + PSA ≥ 10 but ≤ 150; and/or PSA ≥ 20 but ≤ 150. Treatment included ADT (4 or 24 mos, preplanned based on clinical presentation), P (40, 50, or 60 mg/m2/wk) x 7 with EBRT, and whole pelvis EBRT 45 Gy with 19.8 Gy boost (total 64.8 Gy) to prostate bed in RP pts and 25.2 Gy boost (total 70.2 Gy) to prostate in LAPC pts. Results: Between October 1999 and December 2006, 59 pts (29 W, 28 AA) were enrolled (n = 29 LAPC, n = 30 RP); median age 67 yrs, median PSA at trial entry 5.9 (27.5 LAPC, 1.6 RP), median GS 8. Pts were enrolled at different weekly doses of P: 40 mg/m2 n = 10 pts; 50 mg/m2 n = 31 pts; 60 mg/m2 n = 18 pts. ADT for 4 mos was given in 29 pts and for 24 mos in 30 pts. At 40 mg/m2 67/70 (96%), 50 mg/m2 202/217 (93%), and 60 mg/m2 98/126 (78%) planned doses of P were given. There were no acute grade 4 toxicities. Most common grade 3 toxicities were diarrhea 15%, urinary urgency or incontinence 10%, tenesmus 5%, and leukopenia 3%. Median duration of f/u was 75.3 mos, OS 78%, biochemical progression 24/59 (41%) pts, clinical progression 11/59 (19%) pts. Time to biochemical progression was similar between RP vs. LAPC (p = 0.17), between ADT 4 mos vs. 24 mos (p = 0.61), and between AA vs. W (p = 0.54). Conclusions: This trial establishes the feasibility of tri-modality therapy with ADT, EBRT and weekly paclitaxel in high risk PC, both in RP pts and in LAPC pts with intact prostate glands. The maximum tolerated dose of paclitaxel is 50 mg/m2 /wk when given weekly with concurrent radiation to the pelvis and hormone ablation.

No significant financial relationships to disclose.

Gamma Knife stereotactic radiosurgery in the treatment of brain metastases from breast cancer

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Background: Outcomes of gamma knife stereotactic radiosurgery (GK-SRS) for patients with brain metastases specifically from breast cancer have not been well-defined. This study was undertaken to report the long-term experience with GK-SRS in this subset of patients. Methods: From 1995 to 2005, 75 patients with 162 brain lesions were treated with GK-SRS at the University of Maryland Medical Center. Complete follow-up data were available in 65 patients. Additional whole brain radiation therapy (WBRT) was administered to 53 (81.5%) patients. The median WBRT dose was 36.75 Gy (30.0–45.0 Gy). The median number of lesions treated with GK-SRS was 2 (1–8 lesions). The median follow-up, age, and KPS were 7.2 months (0.4–75.7 months), 53.5 years (23–81 years), and 90 (40–100), respectively. The factors included in the univariate and multivariate analyses for overall survival (OS) and progression free survival (PFS) were age, Karnofsky Performance Status (KPS), tumor histology, estrogen receptor status, Her-2-neu status, number of intracranial lesions, and presence of systemic disease. Results: Median PFS and OS from GK-SRS were 5.3 months (0.4–33.2 months) and 8.1 months (0.4–75.7 months), respectively. The 6, 12, and 24 month actuarial PFS were 47.8%, 24.9%, and 9.6% respectively. The 6, 12, and 24 month actuarial OS were 60.7%, 39.1%, and 18.1% respectively. The tumor local control after WBRT and GK-SRS was 87.7%. Radiation necrosis was a complication in 10.8% of patients. Forty-seven (72.3%) patients had neurological symptoms prior to gamma knife treatment. Seven (14.9%) and 9 (19.1%) of these patients experienced symptom resolution and significant symptomatic improvement, respectively. Multivariate and univariate analysis did not reveal any of the prognostic factors in question to be significantly associated with OS nor PFS. Conclusions: This relatively large cohort of patients experienced poor survival outcomes despite aggressive therapy with WBRT and GK-SRS. However, GK-SRS can provide significant symptomatic relief, with acceptable complication rates. More research is required to improve the survival of breast cancer patients with intracranial metastases.

No significant financial relationships to disclose.

Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.