Treatment Outcomes of Patients with Ependymoma Receiving Radiotherapy: A Single Institution Experience.

INTRODUCTION: The study explored the failure pattern and clinical outcomes in patients with ependymoma undergoing radiotherapy. METHODS: Between January 2004 and June 2022, we included 32 patients with ependymoma who underwent radiotherapy as part of the multimodality treatment at our institution. Of these, 27 (84.4%) underwent adjuvant radiotherapy, four received radiotherapy after local recurrence, and one received definitive CyberKnife radiotherapy (21 Gy in three fractions). The median prescribed dose was 54 Gy in patients who received conventional radiotherapy. We analyzed the local progression-free survival (LPFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), overall survival (OS), and potential prognostic factors. RESULTS: The median age was 29.8 years. Approximately 28.1% were pediatric patients. Fifteen tumors (46.9%) were World Health Organization (WHO) grade II, 10 (31.3%) were WHO grade III, and seven (22.8%) were WHO grade I. Among them, 15 patients (46.9%) had posterior fossa tumors, 10 (31.3%) had supratentorial tumors, and seven (22.8%) had spinal tumors. Of the 31 patients who underwent upfront surgical resection, 19 (61.3%) underwent gross total resection or near total resection. Seventeen of 19 patients with first failures (89.5%) had isolated local recurrences. Of the 19 patients with disease progression, 11 (57.9%) were disease-free or had stable disease after salvage therapy, and five (26.3%) had disease-related mortality. Most of the first local recurrences after radiotherapy occurred in the infield (13 of 16, 81.3%). The 5-year LPFS, DMFS, PFS, and OS rates were 48.5%, 89.6%, 45.1%, and 88.4%, respectively, at a median follow-up of 6.25 years. Subtotal resection was associated with poorer LPFS and PFS in patients with intracranial ependymoma (hazard ratio = 3.69, p = 0.018 for LPFS; hazard ratio = 3.20, p = 0.029 for PFS). CONCLUSION: Incorporating radiotherapy into multimodal treatment has led to favorable outcomes in patients with ependymoma, and the extent of resection is a prognostic factor for the local control of intracranial ependymoma.

C-C chemokine receptor 4 (CCR4)-positive regulatory T cells interact with tumor-associated macrophages to facilitate metastatic potential after radiation.

PURPOSE: Our previous study revealed that elevated C-C motif chemokine ligand 2 (CCL2) secretion by irradiated cancer cells recruited C-C motif chemokine receptor 2 (CCR2)-positive myeloid cells and polarized M2-type tumor-associated macrophages (TAMs), promoting lung metastasis in an established mouse model. This study investigated the impact of CCL2 and TAMs on adaptive immunity. METHODS: We assessed the influence of CCL2 and TAMs on adaptive immunity through two ectopic allograft mouse models constructed with MB49 bladder cancer cells and Lewis lung carcinoma cells. Both models exhibited delayed primary tumor growth following radiation therapy (RT), but RT promoted the development of pulmonary metastases in C57BL/6 mice. Additionally, we employed a direct coculture system to investigate the interaction between macrophages and target cells in the context of adaptive immunity. RESULTS: C-C motif chemokine receptor 4 (CCR4)-positive regulatory T cells (Tregs) were recruited to the postirradiated tumor microenvironment (TME). Utilizing a CCR4 antagonist to inhibit CCL2-CCR4 activation reversed the infiltration of CCR4 + Tregs and reduced the incidence of pulmonary metastases. In addition, a positive feedback loop between M2-type TAMs and Tregs was observed. The combined blockade of the CCL2-CCR4 and CCL2-CCR2 signaling pathways further decreased the risk of RT-promoted lung metastasis. CONCLUSION: The recruitment of CCR4 + Tregs to the postirradiated TME increases the metastatic potential of tumor cells through increased interactions with M2-type TAMs. A significant reduction in post-RT lung metastases in ectopic mouse models was achieved by disrupting the recruitment of both CCR4 + Tregs and CCR2 + myeloid cells, which are TAM precursors.

Hybridization Protection Reaction for Sensitive and Robust Gene Expression Profiling of Clinical Formalin-Fixed Paraffin-Embedded Samples.

BACKGROUND: RNA profiling of formalin-fixed paraffin-embedded (FFPE) tumor tissues for the molecular diagnostics of disease prognosis or treatment response is often irreproducible and limited to a handful of biomarkers. This has led to an unmet need for robust multiplexed assays that can profile several RNA biomarkers of interest using a limited amount of specimen. Here, we describe hybridization protection reaction (HPR), which is a novel RNA profiling approach with high reproducibility. METHODS: HPR assays were designed for multiple genes, including 10 radiosensitivity-associated genes, and compared with TaqMan assays. Performance was tested with synthetic RNA fragments, and the ability to analyze RNA was investigated in FPPE samples from 20 normal lung tissues, 40 lung cancer, and 30 esophageal cancer biopsies. RESULTS: Experiments performed on 3 synthetic RNA fragments demonstrated a linear dynamic range of over 1000-fold with a replicate correlation coefficient of 0.99 and high analytical sensitivity between 3.2 to 10 000 pM. Comparison of HPR with standard quantitative reverse transcription polymerase chain reaction on FFPE specimens shows nonsignificant differences with > 99% confidence interval between 2 assays in transcript profiling of 91.7% of test transcripts. In addition, HPR was effectively applied to quantify transcript levels of 10 radiosensitivity-associated genes. CONCLUSIONS: Overall, HPR is an alternative approach for RNA profiling with high sensitivity, reproducibility, robustness, and capability for molecular diagnostics in FFPE tumor biopsy specimens of lung and esophageal cancer.

Efficacy of Liver-Directed Combined Radiotherapy in Locally Advanced Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis.

PURPOSE: Although systemic treatment is the mainstay for advanced hepatocellular carcinoma (HCC), numerous studies have highlighted the added value of local treatment. This study aimed to investigate the clinical efficacy of liver-directed combined radiotherapy (LD combined RT) compared with that of sorafenib, a recommended treatment until recently for locally advanced HCC presenting portal vein tumor thrombosis (PVTT), using a multinational patient cohort. MATERIALS AND METHODS: We identified patients with HCC presenting PVTT treated with either sorafenib or LD combined RT in 10 tertiary hospitals in Asia from 2005 to 2014. Propensity score matching (PSM) was performed to minimize the imbalance between the two groups. The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS) and treatment-related toxicity. RESULTS: A total of 1035 patients (675 in the LD combined RT group and 360 in the sorafenib group) were included in this study. After PSM, 305 patients from each group were included in the analysis. At a median follow-up of 22.5 months, the median OS was 10.6 and 4.2 months for the LD combined RT and sorafenib groups, respectively (p < 0.001). The conversion rate to curative surgery was significantly higher (8.5% vs. 1.0%, p < 0.001), while grade ≥ 3 toxicity was fewer (9.2% vs. 16.1%, p < 0.001) in the LD combined RT group. CONCLUSIONS: LD combined RT improved survival outcomes with a higher conversion rate to curative surgery in patients with locally advanced HCC presenting PVTT. Although further prospective studies are warranted, active multimodal local treatment involving radiotherapy is suggested for locally advanced HCC presenting PVTT.

Survival outcomes and prognostic factors for first-line abiraterone acetate or enzalutamide in patients with metastatic castration-resistant prostate cancer.

PURPOSE: To investigate the survival outcomes of metastatic castration-resistant prostate cancer (mCRPC) patients receiving first-line novel androgen receptor axis-targeted therapies (ARATs) and prognostic factors for patient survival. METHODS: This retrospective study obtained data from 202 patients who started abiraterone acetate or enzalutamide as first-line therapy for mCRPC between 2016 and 2021 from a single academic center. The primary endpoint was overall survival (OS) defined as the interval from the start of ARAT to death, loss to follow-up, or the end of the study period. The secondary endpoints were PSA decline, PSA nadir, and time to nadir (TTN) after ARATs. Kaplan-Meier survival analyses were applied for depicting OS. Cox proportional hazards model with inversed probability of treatment weighing-adjustment was used to validate the effect of patient, disease, and treatment response factors on OS. RESULTS: Among 202 patients, 164 patients were treated with first-line ARATs alone and 38 patients received second-line chemotherapy. The median OS was not reached in patients with first-line ARATs alone and was 38.8 months in those with subsequent chemotherapy after failure from ARATs. OS was not different between the use of abiraterone and enzalutamide, though enzalutamide showed a higher rate of PSA decline ≧ 90% (56% versus 40%, p = 0.021) and longer TTN (5.5 versus 4.7 months, p = 0.019). Multivariable analysis showed that PSA nadir > 2 ng/mL [hazard ratio (HR) 7.04, p < 0.001] and TTN<7 months (HR 2.18, p = 0.012) were independently associated with shorter OS. Patients with both of these poor prognostic factors had worse OS compared to those who had 0-1 factors (HR 9.21, p < 0.001). CONCLUSIONS: Patients with mCRPC who received first-line ARATs had better survival if they had a PSA nadir[Formula: see text]2 ng/mL or a TTN[Formula: see text]7 months. Further study is needed to determine if an early switch in therapy for those in whom neither is achieved may impact OS.

NKG2A and circulating extracellular vesicles are key regulators of natural killer cell activity in prostate cancer after prostatectomy.

Extracellular vesicles (EVs) are an important regulatory factor for natural killer cell activity (NKA) in the tumor microenvironment. The relationship between circulating EVs in the peripheral blood and natural killer (NK) cells in prostate cancer (PCa) is unclear. This study aimed at investigating the key regulators in the interaction between circulating EVs and NK cells in PCa patients before and after tumor removal. NK-cell characteristics were prospectively assessed in 79 patients treated with robot-assisted laparoscopic radical prostatectomy preoperatively and postoperatively. Compared with healthy donors, the existence of prostate tumors increased the number of circulating EVs and altered ligand expression of EVs. Circulating EVs extracted from cancer patients significantly decreased NKA of NK cells compared with those extracted from healthy donors. Upon treatment with an inhibiting antibody or small interfering RNA, natural killer cell protein group 2A (NKG2A) was identified as the main NKA regulator in cancer patients for accepting the signal from circulating EVs. After surgery, NKA was increased and NKG2A expression on NK cells was significantly reduced. The expression of ligands for natural killer cell protein group 2D (NKG2D) on EVs and the level of circulation EVs both significantly increased. With the decrease in NKG2A levels on NK cells and the increase in total NKG2D ligands on circulating EVs, which was increased postoperatively, both NKG2A on NK cells and NKG2D ligands on circulating exosomes are main regulators of NKA restoration after prostatectomy.

Topoisomerase I Inhibition Radiosensitizing Hepatocellular Carcinoma by RNF144A-mediated DNA-PKcs Ubiquitination and Natural Killer Cell Cytotoxicity.

Background and Aims: Topoisomerase I (TOP1) participates the repair of DNA double-strand breaks (DSBs) upon radiation therapy (RT). RNF144A mediates ubiquitination of catalytic subunit of DNA protein kinase (DNA-PKcs), a critical factor in DSB repair. This study aimed to investigate the natural killer (NK) cell-mediated radiosensitization with TOP1 inhibition and the mechanism by DNA-PKcs/RNF144A. Methods: In vitro synergism with TOP1i or cocultured NK cells and RT were evaluated in human hepatocellular carcinoma (HCC) cell lines (Huh7/PLC5) by clonogenic survivals. Orthotopic xenografts were treated with Lipotecan and/or RT. Protein expression was analyzed by western blotting, immunoprecipitation, subcellular fractionation, and confocal microscopy. Results: Lipotecan/RT had a superior synergistic effect to RT on HCC cells. Combined RT/Lipotecan reduced the xenograft size by 7-fold than RT (p<0.05). Lipotecan caused more radiation-induced DNA damage and DNA-PKcs signaling. The expression of major histocompatibility complex class I-related chain A and B (MICA/B) on tumor cells is associated with the sensitivity to NK cell-mediated lysis. Cocultured NK and HCC cells with Lipotecan radiosensitized HCC cells/tissues with the expression of MICA/B. RNF144A increased more in Huh7 cells with combined RT/TOP1i, and reduced the prosurvival function of DNA-PKcs. The effect was reversed by inhibiting the ubiquitin/proteasome system. In comparison, RNF144A decreased through nuclear translocation with the cumulated DNA-PKcs and radio-resistance of PLC5 cells. Conclusions: TOP1i reinforces NK cell-activated anti-HCC effect of RT through RNF144A mediated DNA-PKcs ubiquitination. RNF144A provides a reason for differentiating radiosensitization effect between HCC cells.

Selective inhibition of HDAC6 promotes bladder cancer radiosensitization and mitigates the radiation-induced CXCL1 signalling.

BACKGROUND: Although trimodality therapy resecting tumours followed by chemoradiotherapy is emerged for muscle-invasive bladder cancer (MIBC), chemotherapy produces toxicities. Histone deacetylase inhibitors have been identified as an effective strategy to enhance cancer radiotherapy (RT). METHODS: We examined the role of HDAC6 and specific inhibition of HDAC6 on BC radiosensitivity by performing transcriptomic analysis and mechanism study. RESULTS: HDAC6 knockdown or HDAC6 inhibitor (HDAC6i) tubacin exerted a radiosensitizing effect, including decreased clonogenic survival, increased H3K9ac and α-tubulin acetylation, and accumulated γH2AX, which are similar to the effect of panobinostat, a pan-HDACi, on irradiated BC cells. Transcriptomics of shHDAC6-transduced T24 under irradiation showed that shHDAC6 counteracted RT-induced mRNA expression of CXCL1, SERPINE1, SDC1 and SDC2, which are linked to cell migration, angiogenesis and metastasis. Moreover, tubacin significantly suppressed RT-induced CXCL1 and radiation-enhanced invasion/migration, whereas panobinostat elevated RT-induced CXCL1 expression and invasion/migration abilities. This phenotype was significantly abrogated by anti-CXCL1 antibody, indicating the key regulator of CXCL1 contributing to BC malignancy. Immunohistochemical evaluation of tumours from urothelial carcinoma patients supported the correlation between high CXCL1 expression and reduced survival. CONCLUSION: Unlike pan-HDACi, the selective HDAC6i can enhance BC radiosensitization and effectively inhibit RT-induced oncogenic CXCL1-Snail-signalling, thus further advancing its therapeutic potential with RT.

Efficacy and safety of combined targeted therapy and immunotherapy versus targeted monotherapy in unresectable hepatocellular carcinoma: a systematic review and meta-analysis.

BACKGROUND: Cancer therapy has evolved from non-specific cytotoxic agents to a selective, mechanism-based approach that includes targeted agents and immunotherapy. Although the response to targeted therapies for unresectable hepatocellular carcinoma (HCC) is acceptable with the improved survival, the high tumor recurrence rate and drug-related side effects continue to be problematic. Given that immune checkpoint inhibitor alone are not robust enough to improve survival in unresectable HCC, growing evidence supports the combination of targeted therapy and immunotherapy with synergistic effect. METHODS: Online databases including PubMed, EMBASE, Cochrane Library, and Web of Science were searched for the studies that compared targeted monotherapy with the combination therapy of targeted drug and checkpoint inhibitors in unresectable HCC patients. Eligibility criteria were the presence of at least one measurable lesion as defined by the Response Evaluation Criteria in Solid Tumors (version 1.1) for unresectable HCC patients, an Eastern Cooperative Oncology Group performance status of 0-2, and a Child-Pugh score ≤ 7. Outcome measurements include overall survival (OS), progression-free survival (PFS), and treatment-related adverse event (TRAE). RESULTS: Three phase II/III randomized controlled trials were included in this study. The pooled results showed that combination therapy significantly improved survival than targeted monotherapy, in terms of OS (hazard ratio (HR) = 0.67; 95% confidence interval [CI]: 0.50-0.91) and PFS (HR = 0.58; 95% CI: 0.51-0.67), respectively. In the incidence of grade 3-5 TRAEs, the combination therapy was significantly higher than targeted monotherapy (odds ratio = 1.98; 95% CI: 1.13-3.48). CONCLUSION: For unresectable HCC, combined targeted drug and immunotherapy significantly improved survival compared with targeted monotherapy. However, the incidences of AEs of combinational therapy were higher than targeted monotherapy.

Radiosensitization effect by HDAC inhibition improves NKG2D-dependent natural killer cytotoxicity in hepatocellular carcinoma.

Background: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Radiotherapy (RT) controls HCC unsatisfactorily and temporarily. Histone deacetylase inhibitor (HDACi) is a heterogeneous group of epigenetic therapeutics with promising anticancer effects and synergism in combination with RT. HDACi modulates natural killer (NK) cell ligand expression on tumor cells, and leads to immune evasion of cancer cells. Expressions of NK group 2D (NKG2D) ligands on cancer cells determine the cytotoxic effect by interacting with NKG2D receptor on NK cells. However, the role of NKG2D signaling in HCC upon combined RT and HDACi remains unclear. Method: In vitro co-culture system with NK cells was tested for human and murine HCC cell lines. Pan-HDACi (panobinostat) and specific HDAC4 knockdown (HDAC4-KD) were used for HDAC inhibition. Clonogenic assay and flow cytometry examined HCC cell survival and NKG2D ligand expression, respectively. Syngeneic mouse model was used to validate the radiosensitizing effect in vivo. Results: Combined RT and HDACi/HDAC4-KD significantly enhanced NK cell-related cytotoxicity and increased NKG2D ligands, MICA/MICB expressions in human and RAE-1/H60 expressions in murine HCC cells. Delayed tumor growth in vivo by the combinational treatment of RT and HDACi/HDAC4-KD was shown with the associated NKG2D ligand expressions. However, NKG2D receptor did not significantly change among tumors. Conclusion: Radiosensitizing effect with combined RT and HDAC inhibition increased the expression of NKG2D ligands in HCC cells and enhanced their susceptibility to NK cell-mediated cytotoxicity. These findings imply the potential use of combined RT/HDACi and NK cell-directed immunotherapy.

Does HCC Etiology Impact the Efficacy of Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma? An Asian Liver Radiation Therapy Group Study.

Background/Purpose: The Asian Liver Radiation Therapy Study Group has formed a large and detailed multinational database of outcomes following stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC). Here, we explored the potential impact of HCC etiology on SBRT efficacy. Tumor control probability (TCP) models were established to estimate the likelihood of local control (LC). Methods: Data from 415 patients who were treated with SBRT for HCC were reviewed. Cox proportional hazards models were used to identify key predictors of LC. TCP models accounting for biologic effective dose (BED) and tumor diameter were generated to quantify associations between etiology and LC. Results: Cox models demonstrated that hepatitis C virus (HCV) infection was associated with favorable LC following SBRT (HR=0.52, 95% CI 0.04-0.96, p=0.036). The 2-year LC rate for patients with HCV etiology was 88%, compared to 78% for other patients. Small tumor and high BED were also associated with favorable LC. TCP models demonstrated a 10-20% absolute increase in predicted LC across the range of SBRT doses and tumor sizes. Conclusion: We found a novel association between HCV status and LC after SBRT for HCC that warrants further exploration. If validated in other datasets, our findings could help clinicians tailor SBRT schedules.

Tumor-Derived C-C Motif Ligand 2 Induces the Recruitment and Polarization of Tumor-Associated Macrophages and Increases the Metastatic Potential of Bladder Cancer Cells in the Postirradiated Microenvironment.

PURPOSE: Radiation therapy (RT) is mainly used for bladder preservation in patients with muscle-invasive bladder cancer. The response of urothelial tumors to RT remains unsatisfactory. We investigated the interaction of RT and tumor-associated macrophages (TAMs) in the context of bladder cancer radioresistance. METHODS AND MATERIALS: We evaluated the therapeutic effects of RT and TAM distribution by establishing an ectopic allograft mouse model. A Transwell coculture system was used to simulate the interaction between TAMs and MB49 bladder cancer cells in the tumor microenvironment. Cytokines and chemokines were analyzed in irradiated MB49 cells. Colony formation and Boyden chamber assays were used to assess the cytotoxic effects and the effects of TAMs on MB49 cell invasion, respectively. RESULTS: Local RT delayed primary tumor growth but promoted pulmonary metastases in C57BL/6 mice. Increased secretion of C-C motif chemokine ligand (CCL2) by irradiated MB49 cells, especially in the presence of M1-type TAMs, contributed to the infiltration of bone marrow-derived C-C motif chemokine receptor 2 (CCR2)-positive myeloid cells and the polarization of M1-type TAMs toward the M2 type to promote MB49 cell invasion. Blockade of CCL2-CCR2 activation by a CCR2 antagonist reversed the phenotypic TAM transformation and suppressed pulmonary metastases. CONCLUSIONS: Bladder cancer cells responded to RT by producing CCL2, which recruited TAM precursors from bone marrow and polarized M1-type TAMs toward the M2 type. This phenotypic TAM transformation promoted the pulmonary metastasis of bladder cancer cells after RT. Disrupting the CCL2-CCR2 signaling axis in combination with RT holds promise for improving RT efficacy in bladder cancer.

Longitudinal shear wave elasticity measurements of millimeter-sized biomaterials using a single-element transducer platform.

Temporal variations of the extracellular matrix (ECM) stiffness profoundly impact cellular behaviors, possibly more significantly than the influence of static stiffness. Three-dimensional (3D) cell cultures with tunable matrix stiffness have been utilized to characterize the mechanobiological interactions of elasticity-mediated cellular behaviors. Conventional studies usually perform static interrogations of elasticity at micro-scale resolution. While such studies are essential for investigations of cellular mechanotransduction, few tools are available for depicting the temporal dynamics of the stiffness of the cellular environment, especially for optically turbid millimeter-sized biomaterials. We present a single-element transducer shear wave (SW) elasticity imaging system that is applied to a millimeter-sized, ECM-based cell-laden hydrogel. The single-element ultrasound transducer is used both to generate SWs and to detect their arrival times after being reflected from the side boundaries of the sample. The sample's shear wave speed (SWS) is calculated by applying a time-of-flight algorithm to the reflected SWs. We use this noninvasive and technically straightforward approach to demonstrate that exposing 3D cancer cell cultures to X-ray irradiation induces a temporal change in the SWS. The proposed platform is appropriate for investigating in vitro how a group of cells remodels their surrounding matrix and how changes to their mechanical properties could affect the embedded cells in optically turbid millimeter-sized biomaterials.

Outcomes and Prediction Models for Exclusive Prostate Bed Salvage Radiotherapy among Patients with Biochemical Recurrence after Radical Prostatectomy.

BACKGROUND: The addition of androgen-deprivation therapy (ADT) or pelvic radiation to prostate bed salvage radiotherapy (SRT) has been debated for prostate cancer patients with biochemical recurrence (BCR) after radical prostatectomy. This study aimed to assess the outcomes and propose prediction models for exclusive prostate bed SRT. METHODS: This is a prospective observational cohort study with patients who underwent SRT with a pre-SRT PSA < 1.5 ng/mL after radical prostatectomy. Patients were treated with 70-Gy SRT to the prostate bed exclusively. Kaplan-Meier survival analyses and Cox regression analyses were applied for depicting and predicting BCR-free survival, ADT-free survival, and metastasis-free survival (MFS). Regression-based coefficients were used to develop nomograms. RESULTS: A total of 105 patients were included and 91 patients were eligible. The median follow-up period was 39 months. The 5-year BCR-free survival, ADT-free survival, and MFS were 37%, 50%, and 66%, respectively. Multivariable analysis showed that a pre-SRT PSA < 0.45 ng/mL was the only independent factor associated with longer BCR-free survival (p = 0.034), while a PSA-DT > 8 months had better ADT-free survival (p = 0.008). Patients with a PSA-DT > 8 months showed a 100% MFS and a 43% 5-year absolute benefit in MFS than a PSA-DT ≤ 8 months. All patients with a pre-SRT PSA < 0.45 ng/mL and PSA-DT > 8 months were free from subsequent ADT and any metastasis. CONCLUSIONS: In patients with a PSA < 0.45 ng/mL and PSA-DT > 8 months for post-prostatectomy BCR, prostate bed SRT provided excellent outcomes without the need for concomitant ADT or pelvic radiotherapy.

Peri-radiosurgical administration of bevacizumab improves radiographic response to single and fractionated stereotactic radiosurgery for large brain metastasis.

INTRODUCTION: Stereotactic radiosurgery (SRS) is a standard of care for brain metastases (BM) patients, yet large BM are at a greater risk for radionecrosis and local progression (LP). Concomitant bevacizumab and radiotherapy has been shown to improve outcomes in primary and metastatic brain tumors. This retrospective study investigated the efficacy and safety of concurrent bevacizumab and SRS for large BM. METHODS: From 2015 to 2019, patients with a BM diameter ≥ 2 cm who received either combination therapy (n = 49, SRS + BVZ group), or SRS alone (n = 73, SRS group) were enrolled. Bevacizumab was given peri-radiosurgically with a 2-week interval. Radiographic response was assessed using the RECIST version 1.1. Competing risk and logistic regression analysis were performed to evaluate prognostic factors. RESULTS: Radiographic response was achieved in 41 patients (84%) in the SRS + BVZ group and 37 patients (51%) in the SRS group (p = 0.001). In the multivariate regression analysis, concurrent bevacizumab was independently associated with a better radiographic response (p = 0.003). The cumulative incidences of LP and ≥ grade 2 radionecrosis at 12 months between the SRS + BVZ group and SRS group were 2% versus 6.8%, and 14.3% versus 14.6%, respectively. For patients with BM size ≥ 3 cm, the cumulative incidence of LP was significantly lower in the SRS + BVZ group (p = 0.03). No ≥ grade 4 toxicity was observed in either group. CONCLUSIONS: Concurrent bevacizumab and SRS for large BM is highly effective, with a better radiographic response and minimal excessive treatment-related toxicities. Peri-radiosurgical bevacizumab preferentially reduced the risk of LP, especially for BM size ≥ 3 cm.

CT-Based Collision Prediction Software for External-Beam Radiation Therapy.

PURPOSE: Beam angle optimization is a critical issue for modern radiotherapy (RT) and is a challenging task, especially for large body sizes and noncoplanar designs. Noncoplanar RT techniques may have dosimetric advantages but increase the risk of mechanical collision. We propose a software solution to accurately predict colliding/noncolliding configurations for coplanar and noncoplanar beams. MATERIALS AND METHODS: Individualized software models for two different linear accelerators were built to simulate noncolliding gantry orientations for phantom/patient subjects. The sizes and shapes of the accelerators were delineated based on their manuals and on-site measurements. The external surfaces of the subjects were automatically contoured based on computed tomography (CT) simulations. An Alderson Radiation Therapy phantom was used to predict the accuracy of spatial collision prediction by the software. A gantry collision problem encountered by one patient during initial setup was also used to test the validity of the software. Results: In the comparison between the software estimates and on-site measurements, the noncoplanar collision angles were all predicted within a 5-degree difference in gantry position. The confusion matrix was calculated for each of the two empty accelerator models, and the accuracies were 98.7% and 97.3%. The true positive rates were 97.7% and 96.9%, while the true negative rates were 99.8% and 97.9%, respectively. For the phantom study, the collision angles were predicted within a 5-degree difference. The software successfully predicted the collision problem encountered by the breast cancer patient in the initial setup position and generated shifted coordinates that were validated to correspond to a noncolliding geometry. CONCLUSION: The developed software effectively and accurately predicted collisions for accelerator-only, phantom, and patient setups. This software may help prevent collisions and expand the range of spatially applicable beam angles.

Multi-Institutional Retrospective Study of Radiotherapy for Hepatocellular Carcinoma in the Caudate Lobe.

Background: No studies evaluating the clinical outcomes of radiotherapy (RT) for hepatocellular carcinoma (HCC) in the caudate lobe have been available to date. The purpose of this study was to evaluate the effectiveness and safety of RT for HCC in the caudate lobe. Material and Methods: Seventy patients with HCC in the caudate lobe treated with RT from a multi-institutional database were included in this study. The median equivalent dose in 2 Gy (EQD2) was 80.0 Gy10 (range, 31.3-99.3), and freedom from local progression (FFLP), progression-free survival (PFS), and overall survival (OS) rates were evaluated. Results: The median time of follow-up was 47.9 months (range, 3.4-127), and the 5-year FFLP, PFS, and OS rates were 80.6% [95% confidence interval (CI), 70.8-91.8], 13.8% (95% CI, 7.5-25.4), and 51.3% (95% CI, 39.9-66.1), respectively. In the multivariate analysis, the radiation dose was significantly associated with the FFLP rate [hazard ratio (HR), 0.57 per 10 Gy10 increase, p = 0.001], and the status of FFLP was significantly associated with OS (HR, 2.694, p = 0.014). The overall rate of ≥grade 3 adverse events was 5.7% (4 of 70), and RT-related mortality was not observed. Conclusion: RT for HCC in the caudate lobe showed promising FFLP and OS rates with safe toxicity profiles. These findings suggest that RT may be a promising treatment option for HCC in the caudate lobe.

Randomized multi-reader evaluation of automated detection and segmentation of brain tumors in stereotactic radiosurgery with deep neural networks.

BACKGROUND: Stereotactic radiosurgery (SRS), a validated treatment for brain tumors, requires accurate tumor contouring. This manual segmentation process is time-consuming and prone to substantial inter-practitioner variability. Artificial intelligence (AI) with deep neural networks have increasingly been proposed for use in lesion detection and segmentation but have seldom been validated in a clinical setting. METHODS: We conducted a randomized, cross-modal, multi-reader, multispecialty, multi-case study to evaluate the impact of AI assistance on brain tumor SRS. A state-of-the-art auto-contouring algorithm built on multi-modality imaging and ensemble neural networks was integrated into the clinical workflow. Nine medical professionals contoured the same case series in two reader modes (assisted or unassisted) with a memory washout period of 6 weeks between each section. The case series consisted of 10 algorithm-unseen cases, including five cases of brain metastases, three of meningiomas, and two of acoustic neuromas. Among the nine readers, three experienced experts determined the ground truths of tumor contours. RESULTS: With the AI assistance, the inter-reader agreement significantly increased (Dice similarity coefficient [DSC] from 0.86 to 0.90, P < 0.001). Algorithm-assisted physicians demonstrated a higher sensitivity for lesion detection than unassisted physicians (91.3% vs 82.6%, P = .030). AI assistance improved contouring accuracy, with an average increase in DSC of 0.028, especially for physicians with less SRS experience (average DSC from 0.847 to 0.865, P = .002). In addition, AI assistance improved efficiency with a median of 30.8% time-saving. Less-experienced clinicians gained prominent improvement on contouring accuracy but less benefit in reduction of working hours. By contrast, SRS specialists had a relatively minor advantage in DSC, but greater time-saving with the aid of AI. CONCLUSIONS: Deep learning neural networks can be optimally utilized to improve accuracy and efficiency for the clinical workflow in brain tumor SRS.