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OBJECTIVE Immunotherapy, particularly immune checkpoint inhibitors (ICIs), has revolutionized the treatment of patients with many tumor histologies. Simultaneously, stereotactic body radiotherapy (SBRT) provides excellent local control (LC) and plays an important role in the management of spine metastasis. Promising preclinical work suggests the potential therapeutic benefit of combining SBRT with ICI therapy, but the safety profile of combined therapy is unclear. This study aimed to evaluate the toxicity profile associated with ICI in patients receiving SBRT and, secondarily, whether ICI administration sequence with respect to SBRT affects LC or overall survival (OS) outcomes. METHODS The authors retrospectively reviewed patients with spine metastasis treated with SBRT at an academic center. Patients who received ICI at any point during their disease course were compared to those with the same primary tumor types who did not receive ICI by using Cox proportional hazards analyses. Primary outcomes were long-term sequelae, including radiation-induced spinal cord myelopathy, esophageal stricture, and bowel obstruction. Secondarily, models were created to evaluate OS and LC in the cohort. RESULTS Two hundred forty patients who received SBRT to 299 spine metastases were included in this study. The most common primary tumor types were non–small cell lung cancer (n = 59 [24.6%]) and renal cell carcinoma (n = 55 [22.9%]). One hundred eight patients received at least 1 dose of ICI, with the most common regimen being single-agent anti–PD-1 (n = 80 [74.1%]), followed by combination CTLA-4/PD-1 inhibitors (n = 19 [17.6%]). Three patients experienced long-term radiation-induced sequelae: 2 had esophageal stricture and 1 had bowel obstruction. No patients developed radiation-induced myelopathy. There was no association between receipt of ICI and development of any of these adverse events (p > 0.9). Similarly, ICI was not significantly associated with either LC (p = 0.3) or OS (p = 0.6). In the entire cohort, patients who received ICI prior to beginning SBRT had worse median survival, but ICI sequence with respect to SBRT was not significantly prognostic of either LC (p > 0.3) or OS (p > 0.07); instead, baseline performance status was most predictive of OS (HR 1.38, 95% CI 1.07–1.78, p = 0.012). CONCLUSIONS Treatment regimens that combine ICIs before, concurrent with, and after SBRT for spine metastases are safe, with minimal risk for increased rates of long-term toxicity.

Objectives We evaluated 18F-DCFPyL test–retest repeatability of uptake in normal organs. Methods Twenty-two prostate cancer (PC) patients underwent two 18F-DCFPyL PET scans within 7 days within a prospective clinical trial (NCT03793543). In both PET scans, uptake in normal organs (kidneys, spleen, liver, and salivary and lacrimal glands) was quantified. Repeatability was determined by using within-subject coefficient of variation (wCOV), with lower values indicating improved repeatability. Results For SUVmean, repeatability was high for kidneys, spleen, liver, and parotid glands (wCOV, range: 9.0%–14.3%) and lower for lacrimal (23.9%) and submandibular glands (12.4%). For SUVmax, however, the lacrimal (14.4%) and submandibular glands (6.9%) achieved higher repeatability, while for large organs (kidneys, liver, spleen, and parotid glands), repeatability was low (range: 14.1%–45.2%). Conclusion We found acceptable repeatability of uptake on 18F-DCFPyL PET for normal organs, in particular for SUVmean in the liver or parotid glands. This may have implications for both PSMA-targeted imaging and treatment, as patient selection for radioligand therapy and standardized frameworks for scan interpretation (PROMISE, E-PSMA) rely on uptake in those reference organs.

Inhibition of androgen receptor (AR) signaling has been the mainstay of treatment of advanced prostate cancer (PCa) for the past 80 years. Combination and sequential AR-inhibiting therapies are highly effective palliative therapy, but they are not curative. All patients eventually develop resistance to primary castrating therapy [ie, castration-resistant PCa (CRPC)]. At this point, they are treated with subsequent lines of secondary AR inhibitory therapies. However, resistance to these agents also develops and patients progress to a state we have termed complete androgen inhibition-resistant PCa. This phase of the disease is associated with poor prognosis. At this point, treatment shifts to non-hormonal cytotoxic therapies (eg, chemotherapy and radiopharmaceuticals). However, the majority of PCas remain addicted to signaling through AR throughout the course of the disease. Resistant PCa cells adaptively upregulate AR activity, despite castration and AR inhibitors, via mechanisms such as AR overexpression, gene amplification, mutation, and expression of ligand-independent variants to permit sustained liganded and non-liganded AR signaling. Studies dating back nearly 30 years indicate that high expression of AR induced by prolonged castration becomes a vulnerability of CRPC cells in vitro and in mouse xenografts to supraphysiologic androgen (SPA), which induces cell death and growth arrest in this context. Based on these studies, we developed a counterintuitive treatment called bipolar androgen therapy (BAT) for patients with CRPC, in which SPA is administered intermittently to result in cycling of serum testosterone from the polar extremes of supraphysiologic to near-castrate levels. This rapid cycling is intended to disrupt the adaptive of AR regulation associated with chronic exposure to high or low levels of testosterone, while simultaneously targeting the spectrum of AR expression present in heterogeneous CRPC tumors. We have now tested BAT in >250 patients with CRPC. Here we present a review of these clinical studies, which have demonstrated collectively that BAT can be safely given to men with CRPC, improves quality of life, and produces therapeutic responses in ~30% of patients. As expected, resistance to BAT is associated with adaptive downregulation of AR expression. Intriguingly, this downregulation is associated with restoration of sensitivity to subsequent AR inhibitor therapies.

Supplementary Table from A Phase Ib/II Study of Sabizabulin, a Novel Oral Cytoskeleton Disruptor, in Men with Metastatic Castration-resistant Prostate Cancer with Progression on an Androgen Receptor–targeting Agent

The discovery that androgens play an important role in the progression of prostate cancer led to the development of androgen deprivation therapy (ADT) as a first line of treatment. However, paradoxical growth inhibition has been observed in a subset of prostate cancer upon administration of supraphysiologic levels of testosterone (SupraT), both experimentally and clinically. Here we report that SupraT activates cytoplasmic nucleic acid sensors and induces growth inhibition of SupraT-sensitive prostate cancer cells. This was initiated by the induction of two parallel autophagy-mediated processes, namely, ferritinophagy and nucleophagy. Consequently, autophagosomal DNA activated nucleic acid sensors converge on NFκB to drive immune signaling pathways. Chemokines and cytokines secreted by the tumor cells in response to SupraT resulted in increased migration of cytotoxic immune cells to tumor beds in xenograft models and patient tumors. Collectively, these findings indicate that SupraT may inhibit a subset of prostate cancer by activating nucleic acid sensors and downstream immune signaling.Significance:This study demonstrates that supraphysiologic testosterone induces two parallel autophagy-mediated processes, ferritinophagy and nucleophagy, which then activate nucleic acid sensors to drive immune signaling pathways in prostate cancer.

Supplementary Figures S1-S9

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Purpose:Sabizabulin, an oral cytoskeleton disruptor, was tested in a phase Ib/II clinical study in men with metastatic castration-resistant prostate cancer (mCRPC).Patients and Methods:The phase Ib portion utilized a 3+3 design with escalating daily oral doses of 4.5–81 mg and increasing schedule in 39 patients with mCRPC treated with one or more androgen receptor–targeting agents. Prior taxane chemotherapy was allowed. The phase II portion tested a daily dose of 63 mg in 41 patients with no prior chemotherapy. Efficacy was assessed using PCWG3 and RECIST 1.1 criteria.Results:The MTD was not defined in the phase Ib and the recommended phase II dose was set at 63 mg/day. The most common adverse events (>10% frequency) at the 63 mg oral daily dosing (combined phase Ib/II data) were predominantly grade 1–2 events. Grade ≥3 events included diarrhea (7.4%), fatigue (5.6%), and alanine aminotransferase/aspartate aminotransferase elevations (5.6% and 3.7%, respectively). Neurotoxicity and neutropenia were not observed. Preliminary efficacy data in patients treated with ≥1 continuous cycle of 63 mg or higher included objective response rate in 6 of 29 (20.7%) patients with measurable disease (1 complete, 5 partial) and 14 of 48 (29.2%) patients had PSA declines. The Kaplan–Meier median radiographic progression-free survival was estimated to be 11.4 months (n = 55). Durable responses lasting >2.75 years were observed.Conclusions:This clinical trial demonstrated that chronic oral daily dosing of sabizabulin has a favorable safety profile with preliminary antitumor activity. These data support the ongoing phase III VERACITY trial of sabizabulin in men with mCRPC.

Supplementary Data from A Phase Ib/II Study of Sabizabulin, a Novel Oral Cytoskeleton Disruptor, in Men with Metastatic Castration-resistant Prostate Cancer with Progression on an Androgen Receptor–targeting Agent

Supplementary Figure from A Phase Ib/II Study of Sabizabulin, a Novel Oral Cytoskeleton Disruptor, in Men with Metastatic Castration-resistant Prostate Cancer with Progression on an Androgen Receptor–targeting Agent

Purpose: Sabizabulin, an oral cytoskeleton disruptor, was tested in a phase Ib/II clinical study in men with metastatic castration-resistant prostate cancer (mCRPC). Patients and Methods: The phase Ib portion utilized a 3+3 design with escalating daily oral doses of 4.5–81 mg and increasing schedule in 39 patients with mCRPC treated with one or more androgen receptor–targeting agents. Prior taxane chemotherapy was allowed. The phase II portion tested a daily dose of 63 mg in 41 patients with no prior chemotherapy. Efficacy was assessed using PCWG3 and RECIST 1.1 criteria. Results: The MTD was not defined in the phase Ib and the recommended phase II dose was set at 63 mg/day. The most common adverse events (>10% frequency) at the 63 mg oral daily dosing (combined phase Ib/II data) were predominantly grade 1–2 events. Grade ≥3 events included diarrhea (7.4%), fatigue (5.6%), and alanine aminotransferase/aspartate aminotransferase elevations (5.6% and 3.7%, respectively). Neurotoxicity and neutropenia were not observed. Preliminary efficacy data in patients treated with ≥1 continuous cycle of 63 mg or higher included objective response rate in 6 of 29 (20.7%) patients with measurable disease (1 complete, 5 partial) and 14 of 48 (29.2%) patients had PSA declines. The Kaplan–Meier median radiographic progression-free survival was estimated to be 11.4 months (n = 55). Durable responses lasting >2.75 years were observed. Conclusions: This clinical trial demonstrated that chronic oral daily dosing of sabizabulin has a favorable safety profile with preliminary antitumor activity. These data support the ongoing phase III VERACITY trial of sabizabulin in men with mCRPC.

Bipolar androgen therapy (BAT) is a novel treatment strategy for patients with metastatic castration-resistant prostate cancer (mCRPC). We retrospectively identified patients with mCRPC that achieved deep PSA responses to BAT. All patients with available next-generation molecular sequencing harbored pathogenic mutations in TP53 and/or a homologous recombination DNA repair gene. BACKGROUND: Bipolar androgen therapy (BAT) is an emerging treatment strategy for men with metastatic castration resistant prostate cancer (mCRPC) whereby serum testosterone is cycled from supraphysiologic to near-castrate levels each month. BAT has been shown to induce clinical responses in a significant proportion of patients, some of which are extreme. We explored the clinical and molecular characteristics of patients with mCRPC who achieved deep responses to BAT. METHODS: We conducted a retrospective analysis of patients with mCRPC treated with BAT at Johns Hopkins. We identified 22 of 114 (19%) patients with mCRPC who achieved ≥70% PSA reductions upon treatment with BAT. All patients were treated using 400 mg testosterone cypionate intramuscularly every 28 days, together with continuous LHRH agonist therapy. Clinical-grade DNA sequencing was obtained using commercially available assays. RESULTS: Somatic next-generation sequencing was obtained for 15 of 22 (68%) patients. Of these 15 extreme PSA responders with sequencing data available, All 15 of 15 (100%) harbored a pathogenic mutation in TP53 and/or a homologous recombination DNA repair (HRD) gene. Among the subset of patients with measureable disease (N = 15), 10 patients (67%) achieved an objective response including one patient with a complete response. The median radiographic progression-free survival of these deep PSA responders was 11.3 months (95% CI, 7.9–25.0 months). CONCLUSIONS: We observed an enrichment of TP53 and HRD mutations in mCRPC patients with extreme PSA responses to BAT, with durability lasting about a year. These data support the hypothesis that BAT may most benefit patients with DNA repair-deficient mCRPC. Further studies of BAT in biomarker-selected mCRPC populations (ie, TP53/HRD-mutated) are warranted.

Bipolar androgen therapy (BAT) is a new treatment concept for men whose prostate cancer has become resistant to standard hormone-blocking therapy. Over the past decade, we have performed a series of clinical studies testing BAT in asymptomatic men with castration-resistant prostate cancer. The key findings from these clinical studies are that BAT (a) can be safely administered to asymptomatic patients with metastatic castrate-resistant prostate cancer; (b) does not produce symptomatic disease progression; (c) produces sustained prostate-specific antigen and objective responses in 30%-40% of patients; and (d) can resensitize and prolong response to subsequent antiandrogen therapy. The concept of BAT has generated significant interest from men with prostate cancer, their families, and their physicians. Here we provide a "Patient's Guide" that answers questions about BAT in a form that is accessible to patients, their families, and physicians. Our goal is to provide information to help patients make the most informed decisions they can regarding their prostate cancer treatment.

Increased mitochondrial function may render some cancers vulnerable to mitochondrial inhibitors. Since mitochondrial function is regulated partly by mitochondrial DNA copy number (mtDNAcn), accurate measurements of mtDNAcn could help reveal which cancers are driven by increased mitochondrial function and may be candidates for mitochondrial inhibition. However, prior studies have employed bulk macrodissections that fail to account for cell type-specific or tumor cell heterogeneity in mtDNAcn. These studies have often produced unclear results, particularly in prostate cancer. Herein, we developed a multiplexin situmethod to spatially quantify cell type specific mtDNAcn. We show that mtDNAcn is increased in luminal cells of high-grade prostatic intraepithelial neoplasia (HGPIN), is increased in prostatic adenocarcinomas (PCa), and is further elevated in metastatic castration-resistant prostate cancer. Increased PCa mtDNAcn was validated by two orthogonal methods and is accompanied by increases in mtRNAs and enzymatic activity. Mechanistically, MYC inhibition in prostate cancer cells decreases mtDNA replication and expression of several mtDNA replication genes, and MYC activation in the mouse prostate leads to increased mtDNA levels in the neoplastic prostate cells. Ourin situapproach also revealed elevated mtDNAcn in precancerous lesions of the pancreas and colon/rectum, demonstrating generalization across cancer types using clinical tissue samples.

Objectives PET-based radiomic metrics are increasingly utilized as predictive image biomarkers. However, the repeatability of radiomic features on PET has not been assessed in a test–retest setting. The prostate-specific membrane antigen-targeted compound 18F-DCFPyL is a high-affinity, high-contrast PET agent that we utilized in a test-retest cohort of men with metastatic prostate cancer (PC). Methods Data of 21 patients enrolled in a prospective clinical trial with histologically proven PC underwent two 18F-DCFPyL PET scans within 7 days, using identical acquisition and reconstruction parameters. Sites of disease were segmented and a set of 29 different radiomic parameters were assessed on both scans. We determined repeatability of quantification by using Pearson's correlations, within-subject coefficient of variation (wCOV), and Bland–Altman analysis. Results In total, 230 lesions (177 bone, 38 lymph nodes, 15 others) were assessed on both scans. For all investigated radiomic features, a broad range of inter-scan correlation was found (r, 0.07–0.95), with acceptable reproducibility for entropy and homogeneity (wCOV, 16.0% and 12.7%, respectively). On Bland–Altman analysis, no systematic increase or decrease between the scans was observed for either parameter (±1.96 SD: 1.07/−1.30, 0.23/−0.18, respectively). The remaining 27 tested radiomic metrics, however, achieved unacceptable high wCOV (≥21.7%). Conclusion Many common radiomic features derived from a test–retest PET study had poor repeatability. Only Entropy and homogeneity achieved good repeatability, supporting the notion that those image biomarkers may be incorporated in future clinical trials. Those radiomic features based on high frequency aspects of images appear to lack the repeatability on PET to justify further study.

The treatment landscape of renal cell carcinoma is rapidly evolving, especially with the introduction and approval of immune checkpoint inhibitor combination therapies. Clinical trial data show substantial improvements in patient outcomes, and now results in the real-world setting support the use of these combinations.

Testosterone is the canonical growth factor of prostate cancer but can paradoxically suppress its growth when present at supraphysiological levels. We have previously demonstrated that the cyclical administration of supraphysiological androgen (SPA), entitled Bipolar Androgen Therapy (BAT), can result in tumor regression and clinical benefit for patients with castration-resistant prostate cancer [1–5]. However, predictors and mechanisms of response and resistance have been ill-defined. Here we show that growth inhibition of prostate cancer models by SPA requires high androgen receptor (AR) abundance and activity and is driven in part by downregulation of MYC. Using matched sequential patient biopsies, we show that high pre-treatment AR activity predicts downregulation of MYC, clinical response, and prolonged progression-free and overall survival for patients on BAT. BAT induced strong downregulation of AR in all patients, which is shown to be a primary mechanism of acquired resistance to SPA. Acquired resistance can be overcome by alternating SPA with the AR inhibitor enzalutamide, which induces adaptive upregulation of AR and re-sensitizes prostate cancer to SPA. This work identifies a predictive biomarker of response to BAT and supports a new treatment paradigm for prostate cancer involving alternating between AR inhibition and activation.

In patients with prostate cancer (PC) receiving prostate-specific membrane antigen- (PSMA-) targeted radioligand therapy (RLT), higher baseline standardized uptake values (SUVs) are linked to improved outcome. Thus, readers deciding on RLT must have certainty on the repeatability of PSMA uptake metrics. As such, we aimed to evaluate the test-retest repeatability of lesion uptake in a large cohort of patients imaged withIn this prospective, IRB-approved trial (NCT03793543), 21 patients with history of histologically proven PC underwent twoIn total, 230 pairs of lesions (177 bone, 38 LN, and 15 other) were delineated, demonstrating a wide range of SUVIn this prospective test-retest setting, SUV parameters demonstrated high repeatability, in particular in LNs, while volumetric parameters demonstrated low repeatability. Further, the large number of lesions and wide distribution of SUVs included in this analysis allowed for the demonstration of a dependence of repeatability on SUV, with higher SUVs having more robust repeatability.

Background: Emerging data suggest that metastasis is a spectrum of disease burden rather than a binary state, and local therapies, such as radiation, might improve outcomes in oligometastasis. However, current definitions of oligometastasis are solely numerical. Objective: To characterize the somatic mutational landscape across the disease spectrum of metastatic castration-sensitive prostate cancer (mCSPC) to elucidate a biological definition of oligometastatic CSPC. Design, setting, and participants: This was a retrospective study of men with mCSPC who underwent clinical-grade sequencing of their tumors (269 primary tumor, 25 metastatic sites). Patients were classified as having biochemically recurrent (ie, micrometa-static), metachronous oligometastatic (5 lesions), or de novo metastatic (metastasis at diagnosis) disease. Outcome measurements and statistical analysis: We measured the frequency of driver mutations across metastatic classifications and the genomic associations with radiographic progression-free survival (rPFS) and time to castrate-resistant prostate cancer (CRPC). Results and limitations: The frequency of driver mutations in TP53 (p = 0.01), WNT (p = 0.08), and cell cycle (p = 0.04) genes increased across the mCSPC spectrum. TP53 mutation was associated with shorter rPFS (26.7 vs 48.6 mo; p = 0.002), and time to CRPC (95.6 vs 155.8 mo; p = 0.02) in men with oligometastasis, and identified men with polymetastasis with better rPFS (TP53 wild-type, 42.7 mo; TP53 mutated, 18.5 mo; p = 0.01). Mutations in TP53 (incidence rate ratio [IRR] 1.45; p = 0.004) and DNA double-strand break repair (IRR 1.61; p < 0.001) were associated with a higher number of metastases. Mutations in TP53 were also independently associated with shorter rPFS (hazard ratio [HR] 1.59; p = 0.03) and the development of CRPC (HR 1.71; p = 0.01) on multivariable analysis. This study was limited by its retrospective nature, sample size, and the use of commercially available sequencing platforms, resulting in a limited predefined set of genes examined. Conclusions: Somatic mutational profiles reveal a spectrum of metastatic biology that helps in redefining oligometastasis beyond a simple binary state of lesion enumeration. Patient summary: Oligometastatic prostate cancer is typically defined as less than three to five metastatic lesions and evidence suggests that using radiation or surgery to treat these sites improves clinical outcomes. As of now, treatment decisions for oligometastasis are solely defined according to the number of lesions. However, this study suggests that tumor mutational profiles can provide a biological definition of oligometastasis and complement currently used numerical definitions. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of European Association of Urology.

Purpose/Objective(s) Radiotherapy, especially high-dose radiation in the form of stereotactic body radiotherapy (SBRT), may stimulate the therapeutic effect of immune checkpoint inhibitors (ICIs). Both SBRT and ICIs play an increasingly important role in the management of spine metastasis. We hypothesize that SBRT and ICI may act synergistically to improve the outcomes of patients with spine metastasis. Materials/Methods We retrospectively reviewed patients with spine metastasis treated with SBRT at an academic center between 2009 and 2019. Patients who received ICI at any point during their disease course were compared to those with the same primary tumor types who did not receive ICI. Cox proportional hazard analyses were performed for overall survival (OS) and local control (LC), adjusting for primary tumor type, age, performance status, and prior spine surgery and/or radiation. Results 153 patients with 194 unique spine lesions were treated with SBRT. The most common primary tumor types were renal cell carcinoma (RCC), non-small cell lung cancer (N = 48, 31% each), colorectal cancer (N = 21, 14%), melanoma and liver cancer (N = 10, 6% each). 82 patients received at least one course of ICI. The most common type of ICI was single-agent anti-PD-1 (N = 71, 88%), followed by dual anti-CTLA-4/PD-1 inhibitors (N = 14, 17%). Of patients receiving ICI, 44 (53.6%) initiated ICI before SBRT, and 38 (46.4%) received ICI after SBRT. The median survival (MS) after SBRT was 14.8 months (95% confidence interval [CI] 11.4-19.6). On univariable analysis, MS was significantly longer for patients starting ICI after SBRT (27.3 months, 95% CI 16.0-33.9) than for those who did not receive any ICI (MS 11.3 months, 95% CI 8.9-15.8, P = 0.04). Patients with RCC (HR 0.67, 95% CI 0.45-1.00, P = 0.05) and higher body mass index (BMI, HR 0.97 as continuous variable, 95% CI 0.93-1.00, P = 0.05) trended toward longer OS. On multivariable analysis after adjusting for primary tumor type, performance status and BMI, only ICI treatment after SBRT was significantly associated with increased survival (HR 0.62, 95% CI 0.39-0.98, P = 0.04). LC after SBRT was numerically higher in patients receiving ICI (1-year LC 91.3%, 95% CI 82.4-95.8%; 2-year 79.7%, 95% CI 65.7-88.5%), than those who did not (1-year 81.5%, 95% CI 65.9-90.5%; 2-year LC 55.5%, 95% CI 35.6-71.4%), although this was not statistically significant (P = 0.18). ICI Initiation before SBRT trended toward superior LC compared to no ICI (multivariable HR 0.49, 95% CI 0.22-1.08, P = 0.08). Both epidural disease and paraspinal extension were associated with worse LC on univariable and multivariable analyses. Conclusion ICIs may enhance survival and tumor control after SBRT for patients with spine metastasis. Post-SBRT ICI may improve systemic disease control and survival, while pre-SBRT ICI may augment LC. Further research is needed to maximize the synergy between these two treatment modalities. Author Disclosure X. Chen: None. M.C. LeCompte: None. L.R. Kleinberg: Research Grant; Novartis, Novocure, Accuray, Arbor. Honoraria; Accuray. Advisory Board; Novocure. Travel Expenses; Accuray. R.K. Hales: Research Grant; Genentech. K. Voong: Research Grant; Radiation Oncology Institute, Lung Cancer Research Foundation, Canon, Inc. P. Forde: Research Grant; Bristol Myers-Squibb, AstraZeneca, Kyowa-Kirin, Novartis. Honoraria; Bristol Myers-Squibb, AstraZeneca, Novartis, Merck, AbbVie, EMD, Inivata. J.R. Brahmer: Research Grant; AstraZeneca, Bristol Myers Squibb, Genentech/Roche, Merck, RAPT Therapeutics, Revolution Medicines. Consultant; Amgen, Bristol Myers Squibb, Genentech, Eli Lilly, GlaxoSmithKline, Merck, Sanofi. M. Markowski: Honoraria; Clovis Oncology, Exelixis. D.M. Ryan II: None. L. Lo: None. D.M. Sciubba: Consultant; Medtronic, DePuy-Synthes, Baxter. K.J. Redmond: Research Grant; Elekta AB, Accuray. Honoraria; AstraZeneca, Accuray. Travel Expenses; Elekta AB, Accuray.