Clinical Experience of Intrafractional Motion Monitoring of Patients Under Head and Neck Radiation Therapy Using ExacTrac Dynamic System.

Purpose: The combination of surface-guided radiation therapy (SGRT) and image-guided radiation therapy (IGRT) can provide complementary information of patient positioning throughout treatments. The ExacTrac Dynamic (EXTD) system is a combined SGRT and IGRT system that can provide real-time motion detection via optical surface and thermal tracking during treatment delivery, with stereoscopic x-ray for positional verification. The purpose of this study was to examine the performance of EXTD for intrafractional motion monitoring using real clinical cases. Methods and Materials: Treatment log files exported from EXTD for 40 patients with 335 fractions were retrospectively analyzed. Frequency of beam-hold triggered during treatments were recorded, with the comparison of shifts detected by optical surface tracking (EXTD_Thml) and x-ray verification (EXTD_Xray). Results: Among the 335 fractions, automatic beam-holds were triggered 41 times, followed by x-ray positional verification with internal anatomy. The difference of shifts detected by EXTD_Thml and EXTD_Xray were less than 1 mm and 1° in translational and rotational directions, respectively. After x-ray verification, none of them required the application of positional correction. Conclusions: The availability of x-ray imaging with optical surface tracking in EXTD is essential to verify whether geometric shifts are required to correct patient position. Considering the ability of continuous monitoring of patient positions with optical surface tracking and internal imaging, EXTD is an effective tool for intrafractional motion monitoring during radiation therapy.

Early detection of nasopharyngeal carcinoma: performance of a short contrast-free screening magnetic resonance imaging.

BACKGROUND: Although contrast-enhanced magnetic resonance imaging (MRI) detects early-stage nasopharyngeal carcinoma (NPC) not detected by endoscopic-guided biopsy (EGB), a short contrast-free screening MRI would be desirable for NPC screening programs. This study evaluated a screening MRI in a plasma Epstein-Barr virus (EBV)-DNA NPC screening program. METHODS: EBV-DNA-screen-positive patients underwent endoscopy, and endoscopy-positive patients underwent EGB. EGB was negative if the biopsy was negative or was not performed. Patients also underwent a screening MRI. Diagnostic performance was based on histologic confirmation of NPC in the initial study or during a follow-up period of at least 2 years. RESULTS: The study prospectively recruited 354 patients for MRI and endoscopy; 40/354 (11.3%) endoscopy-positive patients underwent EGB. Eighteen had NPC (5.1%), and 336 without NPC (94.9%) were followed up for a median of 44.8 months. MRI detected additional NPCs in 3/18 (16.7%) endoscopy-negative and 2/18 (11.1%) EGB-negative patients (stage I/II, n = 4; stage III, n = 1). None of the 24 EGB-negative patients who were MRI-negative had NPC. MRI missed NPC in 2/18 (11.1%), one of which was also endoscopy-negative. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MRI, endoscopy, and EGB were 88.9%, 91.1%, 34.8%, 99.4%, and 91.0%; 77.8%, 92.3%, 35.0%, 98.7%, and 91.5%; and 66.7%, 92.3%, 31.6%, 98.1%, and 91.0%, respectively. CONCLUSION: A quick contrast-free screening MRI complements endoscopy in NPC screening programs. In EBV-screen-positive patients, MRI enables early detection of NPC that is endoscopically occult or negative on EGB and increases confidence that NPC has not been missed.

Preclinical evaluation of the VEGF/Ang2 bispecific nanobody BI 836880 in nasopharyngeal carcinoma models.

Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) is endemic to parts of Asia and overexpression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α are common in NPC. Anti-vascular agents have known clinical activity in patients with recurrent/ metastatic NPC and in this study, we investigated the anti-tumor effect of BI 836880, a humanized bispecific nanobody against VEGF and angiopoietin-2 (Ang2), in preclinical models of EBV-positive and EBV-negative NPC. The efficacy of BI 836880 was also compared with bevacizumab, a recombinant humanized monoclonal antibody against VEGF. We found that BI 836880 could exert growth-inhibitory effect on endothelial cells (HUVEC-C) and the EBV-negative NPC cell line (HK1), but to a lesser extent in the EBV-positive NPC cell lines, C17C and C666-1. In patients-derived xenograft (PDX) models of NPC - Xeno-2117 and Xeno-666, BI 836880 could suppress tumor growth and Ki67, as well as induce tumor necrosis and reduce microvessel density. Moreover, treatment with BI 836880 increased the level of macrophage infiltration in both PDX tumor models of NPC, suggesting that BI 836880 may exert immunomodulatory effect on the NPC immune microenvironment. When compared with bevacizumab, BI 836880 appeared to show at least comparable activity as bevacizumab in terms of its anti-proliferative and anti-angiogenic effects. This study showed that BI 836880 has anti-proliferative, anti-angiogenic and possibly immunomodulatory effect in clinical models of NPC, therefore the dual targeting of VEGF and Ang2 signaling in NPC should be further investigated.

Role of chemotherapy in patients with nasopharynx carcinoma treated with radiotherapy (MAC-NPC): an updated individual patient data network meta-analysis.

BACKGROUND: The meta-analysis of chemotherapy for nasopharynx carcinoma (MAC-NPC) collaborative group previously showed that the addition of adjuvant chemotherapy to concomitant chemoradiotherapy had the highest survival benefit of the studied treatment regimens in nasopharyngeal carcinoma. Due to the publication of new trials on induction chemotherapy, we updated the network meta-analysis. METHODS: For this individual patient data network meta-analysis, trials of radiotherapy with or without chemotherapy in patients with non-metastatic nasopharyngeal carcinoma that completed accrual before Dec 31, 2016, were identified and updated individual patient data were obtained. Both general databases (eg, PubMed and Web of Science) and Chinese medical literature databases were searched. Overall survival was the primary endpoint. A frequentist network meta-analysis approach with a two-step random effect stratified by trial based on hazard ratio Peto estimator was used. Global Cochran Q statistic was used to assess homogeneity and consistency, and p score to rank treatments, with higher scores indicating higher benefit therapies. Treatments were grouped into the following categories: radiotherapy alone, induction chemotherapy followed by radiotherapy, induction chemotherapy without taxanes followed by chemoradiotherapy, induction chemotherapy with taxanes followed by chemoradiotherapy, chemoradiotherapy, chemoradiotherapy followed by adjuvant chemotherapy, and radiotherapy followed by adjuvant chemotherapy. This study is registered with PROSPERO, CRD42016042524. FINDINGS: The network comprised 28 trials and included 8214 patients (6133 [74·7%] were men, 2073 [25·2%] were women, and eight [0·1%] had missing data) enrolled between Jan 1, 1988, and Dec 31, 2016. Median follow-up was 7·6 years (IQR 6·2-13·3). There was no evidence of heterogeneity (p=0·18), and inconsistency was borderline (p=0·10). The three treatments with the highest benefit for overall survival were induction chemotherapy with taxanes followed by chemoradiotherapy (hazard ratio 0·75; 95% CI 0·59-0·96; p score 92%), induction chemotherapy without taxanes followed by chemoradiotherapy (0·81; 0·69-0·95; p score 87%), and chemoradiotherapy followed by adjuvant chemotherapy (0·88; 0·75-1·04; p score 72%), compared with concomitant chemoradiotherapy (p score 46%). INTERPRETATION: The inclusion of new trials modified the conclusion of the previous network meta-analysis. In this updated network meta-analysis, the addition of either induction chemotherapy or adjuvant chemotherapy to chemoradiotherapy improved overall survival over chemoradiotherapy alone in nasopharyngeal carcinoma. FUNDING: Institut National du Cancer and Ligue Nationale Contre le Cancer.

Long-term Outcomes of Bevacizumab and Chemoradiation for Locoregionally Advanced Nasopharyngeal Carcinoma: A Nonrandomized Controlled Trial.

Importance: The long-term outcomes associated with adding bevacizumab, a vascular endothelial growth factor inhibitor, to standard chemoradiation have continued to be favorable for a group of patients with locoregionally advanced nasopharyngeal carcinoma (NPC). Objective: To assess long-term toxic effects and clinical outcomes associated with chemotherapy, radiation therapy (RT), and bevacizumab for NPC. Design, Setting, and Participants: This single-arm phase II nonrandomized controlled trial was conducted by the National Cancer Trials Network group and NRG Oncology (formerly Radiation Therapy Oncology Group), with accrual from December 13, 2006, to February 5, 2009, and data analysis from June 26 to July 1, 2019. The study was conducted at 19 cancer centers with a median (IQR) follow-up of 9.0 (7.7-9.3) years. Included patients were adults (aged ≥18 years) with NPC that was World Health Organization (WHO) histologic grade I to IIb or III, American Joint Committee on Cancer stage IIB or greater, and with or without lymph node involvement. Interventions: Patients received 3 cycles of bevacizumab (15 mg/kg) concurrently with standard cisplatin (100 mg/m2) and RT (69.96 Gy) followed by 3 cycles of adjuvant bevacizumab (15 mg/kg) given concurrently with cisplatin (80 mg/m2) and fluorouracil (1000 mg/m2/d). Main Outcomes and Measures: The primary end point was grade 4 hemorrhage or grade 5 adverse events in the first year. Secondary end points were locoregional progression-free (LRPF) interval, distant metastasis-free (DMF) interval, progression-free survival (PFS), overall survival (OS), and other adverse events. Long-term toxic effects and clinical outcomes were reported due to the limited follow-up in the initial report for this trial and the importance of long-term outcomes when combining bevacizumab with chemoradiation. Results: Among 46 patients with NPC who were enrolled, 44 patients were analyzed (29 males [65.9%]; 23 Asian [52.3%], 2 Black [4.5%], and 16 White [36.4%]; 38 not Hispanic [86.4%]; median [IQR] age, 48.5 [39.0-56.0] years). There were 33 patients with a Zubrod performance status of 0, indicating that they were fully functional and asymptomatic (75.0%); 32 patients with a WHO histologic grade of IIb or III (72.7%); and 39 patients with stage III or IVB disease (88.6%). Among analyzed patients, 42 individuals received radiation therapy of 69.96 Gy or greater (95.5%; dose range, 65.72-70.00 Gy); 30 patients received 3 cycles of cisplatin (68.2%) with RT, and 31 patients received 3 cycles of bevacizumab with RT (70.5%); this was followed by 3 cycles of adjuvant cisplatin in 21 patients (47.7%), fluorouracil in 24 patients (54.5%), and bevacizumab in 23 patients (52.3%). No grade 4 hemorrhage or grade 5 AEs were reported in the first year or thereafter. Late grade 3 AEs occurred in 16 patients (36.4%), including 7 patients with dysphagia (15.9%), 6 patients with hearing impairment (13.6%), and 2 patients with dry mouth (4.5%). The 1- and 5-year rates of feeding tube use were 5 of 41 patients (12.2%) and 0 of 27 patients, respectively. There were 19 patients (43.2%) who progressed or died without disease progression (6 patients with locoregional progression [13.6%], 8 patients with distant progression [18.2%], and 5 patients who died without progression [11.4%]). The 5- and 7-year rates were 79.5% (95% CI, 67.6%-91.5%) and 69.7% (95% CI, 55.9%-83.5%) for OS, 61.2% (95% CI, 46.8%-75.6%) and 56.3% (95% CI, 41.5%-71.1%) for PFS, 74.9% (95% CI, 61.4%-86.6%) and 72.3% (95% CI, 58.4%-84.7%) for LRPF interval, and 79.5% (95% CI,66.4%-90.0%) for both times for DMF interval. Among 13 patients who died, death was due to disease in 8 patients (61.5%). Conclusions and Relevance: In this nonrandomized controlled trial, no grade 4 hemorrhage or grade 5 AEs were reported in the first year or thereafter among patients with NPC receiving bevacizumab combined with chemoradiation. The rate of distant metastasis was low although 89% of patients had stage III to IVB disease, suggesting that further investigation may be warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT00408694.

Fragmentation landscape of cell-free DNA revealed by deconvolutional analysis of end motifs.

Cell-free DNA (cfDNA) fragmentation is nonrandom, at least partially mediated by various DNA nucleases, forming characteristic cfDNA end motifs. However, there is a paucity of tools for deciphering the relative contributions of cfDNA cleavage patterns related to underlying fragmentation factors. In this study, through non-negative matrix factorization algorithm, we used 256 5' 4-mer end motifs to identify distinct types of cfDNA cleavage patterns, referred to as "founder" end-motif profiles (F-profiles). F-profiles were associated with different DNA nucleases based on whether such patterns were disrupted in nuclease-knockout mouse models. Contributions of individual F-profiles in a cfDNA sample could be determined by deconvolutional analysis. We analyzed 93 murine cfDNA samples of different nuclease-deficient mice and identified six types of F-profiles. F-profiles I, II, and III were linked to deoxyribonuclease 1 like 3 (DNASE1L3), deoxyribonuclease 1 (DNASE1), and DNA fragmentation factor subunit beta (DFFB), respectively. We revealed that 42.9% of plasma cfDNA molecules were attributed to DNASE1L3-mediated fragmentation, whereas 43.4% of urinary cfDNA molecules involved DNASE1-mediated fragmentation. We further demonstrated that the relative contributions of F-profiles were useful to inform pathological states, such as autoimmune disorders and cancer. Among the six F-profiles, the use of F-profile I could inform the human patients with systemic lupus erythematosus. F-profile VI could be used to detect individuals with hepatocellular carcinoma, with an area under the receiver operating characteristic curve of 0.97. F-profile VI was more prominent in patients with nasopharyngeal carcinoma undergoing chemoradiotherapy. We proposed that this profile might be related to oxidative stress.

Frequency of Peripheral CD8+ T Cells Expressing Chemo-Attractant Receptors CCR1, 4 and 5 Increases in NPC Patients with EBV Clearance upon Radiotherapy.

Radiotherapy (RT) is the standard-of-care for Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC), where the post-RT clearance of plasma EBV DNA is prognostic. Currently, it is not known whether the post-RT clearance of plasma EBV DNA is related to the presence of circulating T-cell subsets. Blood samples from NPC patients were used to assess the frequency of T-cell subsets relating to differentiation, co-signaling and chemotaxis. Patients with undetectable versus detectable plasma EBV DNA levels post-RT were categorized as clearers vs. non-clearers. Clearers had a lower frequency of PD1+CD8+ T cells as well as CXCR3+CD8+ T cells during RT compared to non-clearers. Clearers exclusively showed a temporal increase in chemo-attractant receptors CCR1, 4 and/or 5, expressing CD8+ T cells upon RT. The increase in CCR-expressing CD8+ T cells was accompanied by a drop in naïve CD8+ T cells and an increase in OX40+CD8+ T cells. Upon stratifying these patients based on clinical outcome, the dynamics of CCR-expressing CD8+ T cells were in concordance with the non-recurrence of NPC. In a second cohort, non-recurrence associated with higher quantities of circulating CCL14 and CCL15. Collectively, our findings relate plasma EBV DNA clearance post-RT to T-cell chemotaxis, which requires validation in larger cohorts.

A novel tumor suppressor encoded by a 1p36.3 lncRNA functions as a phosphoinositide-binding protein repressing AKT phosphorylation/activation and promoting autophagy.

Peptides/small proteins, encoded by noncanonical open reading frames (ORF) of previously claimed non-coding RNAs, have recently been recognized possessing important biological functions, but largely uncharacterized. 1p36 is an important tumor suppressor gene (TSG) locus frequently deleted in multiple cancers, with critical TSGs like TP73, PRDM16, and CHD5 already validated. Our CpG methylome analysis identified a silenced 1p36.3 gene KIAA0495, previously thought coding long non-coding RNA. We found that the open reading frame 2 of KIAA0495 is actually protein-coding and translating, encoding a small protein SP0495. KIAA0495 transcript is broadly expressed in multiple normal tissues, but frequently silenced by promoter CpG methylation in multiple tumor cell lines and primary tumors including colorectal, esophageal and breast cancers. Its downregulation/methylation is associated with poor survival of cancer patients. SP0495 induces tumor cell apoptosis, cell cycle arrest, senescence and autophagy, and inhibits tumor cell growth in vitro and in vivo. Mechanistically, SP0495 binds to phosphoinositides (PtdIns(3)P, PtdIns(3,5)P2) as a lipid-binding protein, inhibits AKT phosphorylation and its downstream signaling, and further represses oncogenic AKT/mTOR, NF-κB, and Wnt/ß-catenin signaling. SP0495 also regulates the stability of autophagy regulators BECN1 and SQSTM1/p62 through modulating phosphoinositides turnover and autophagic/proteasomal degradation. Thus, we discovered and validated a 1p36.3 small protein SP0495, functioning as a novel tumor suppressor regulating AKT signaling activation and autophagy as a phosphoinositide-binding protein, being frequently inactivated by promoter methylation in multiple tumors as a potential biomarker.

Recommendations for Epstein-Barr virus-based screening for nasopharyngeal cancer in high- and intermediate-risk regions.

A meeting of experts was held in November 2021 to review and discuss available data on performance of Epstein-Barr virus (EBV)-based approaches to screen for early stage nasopharyngeal carcinoma (NPC) and methods for the investigation and management of screen-positive individuals. Serum EBV antibody and plasma EBV DNA testing methods were considered. Both approaches were found to have favorable performance characteristics and to be cost-effective in high-risk populations. In addition to endoscopy, use of magnetic resonance imaging (MRI) to investigate screen-positive individuals was found to increase the sensitivity of NPC detection with minimal impact on cost-effectiveness of the screening program.

Plasma Epstein-Barr Virus DNA and Risk of Future Nasopharyngeal Cancer.

BACKGROUND: We previously conducted a prospective study to show that nasopharyngeal cancer (NPC) screening with circulating Epstein­Barr virus (EBV) DNA analysis can improve survival. However, the long-term significance of positive results in individuals without cancer was unclear. METHODS: We conducted a second-round screening at a median of 43 months after the initial screening. Participants with detectable plasma EBV DNA were retested in 4 weeks, and those with persistently positive results were investigated with nasal endoscopy and magnetic resonance imaging. RESULTS: Of the 20,174 volunteers who participated in the first-round screening, 17,838 (88.6%) were rescreened. Among them, 423 (2.37%) had persistently detectable plasma EBV DNA. Twenty-four patients were identified as having NPC. A significantly higher proportion of patients had stage I/II cancer than in a historical cohort (67% vs. 20%; chi-square test, P<0.001), and they had superior 3-year progression-free survival (100% vs. 78.8%). Compared with participants with undetectable plasma EBV DNA in the first round of screening, participants with transiently and persistently positive results in the first round were more likely to have a cancer identified in the second round, with relative risks of 4.4 (95% confidence interval, 1.3 to 15.0) and 16.8 (95% confidence interval, 5.7 to 49.6), respectively. CONCLUSIONS: Individuals with detectable plasma EBV DNA but without an immediately identifiable NPC were more likely to have the cancer identified in another round of screening performed 3 to 5 years later. (Funded by Kadoorie Charitable Foundation and others; ClinicalTrials.gov number, NCT02063399.)

Magnetic-field-modulated radiotherapy (MagMRT) in inhomogeneous medium and its potential applications.

Objective.To study the effects of magnetic field gradients on the dose deposition in an inhomogeneous medium and to present the benefits offered by magnetic-field-modulated radiotherapy (MagMRT) under multiple radiation beams.Approach.Monte Carlo simulations were performed using the Geant4 simulation toolkit with a 7 MV photon beam from an Elekta Unity system. A water cuboid embedded with material slabs of water, bone, lung or air was used to study the effects of MagMRT within inhomogeneous medium. Two cylindrical water phantoms, with and without a toroidal lung insert embedded, were used to study the effects of MagMRT under single, opposing or four cardinal radiation beams. Optimized magnetic field variations in the form of a wavelet were used to induce dose modulation within the material slabs or at the iso-center of the phantoms.Main results.The magnitudes of the dose enhancement and reduction induced by the magnetic field gradients become more prominent in a medium of lower density. A maximum dose increase of 6.5% and a decrease of 4.8% were found inside bone, while an increase of 20.4% and a decrease of 13.9% were found in lung tissue. Under multiple radiation beams, the dose enhancement can be induced at the iso-center while the dose reduction occurs in regions around the tumor. For the case with four cardinal beams irradiating a homogeneous water cylinder, an 8.4% of dose enhancement and a 2.4% of dose reduction were found. When a toroidal lung insert was embedded, a maximum dose enhancement of 9.5% and a reduction of 17.0% were produced for anterior-posterior opposing fields.Significance.With an optimized magnetic field gradient, MagMRT can induce a dose boost to the target while producing a better sparing to the surrounding normal tissue, resulting in a sharper dose fall-off in all directions outside the target volume.

The effect of material assignment in nasal cavity on dose calculation for nasopharyngeal carcinoma (NPC) using Acuros XB.

PURPOSE: To evaluate the effect of material assignment in nasal cavity on dose calculation for the volumetric modulated arc therapy (VMAT) of nasopharyngeal carcinoma (NPC) using Acuros XB (AXB) algorithm. METHODS: The VMAT plans of 30 patients with NPC were calculated using AXB with material auto-assignment of nasal cavity to lung and reassignment to air respectively. The doses to the planning target volumes (PTVs) overlapping with nasal cavity with material auto-assignment of lung (AXB_Lung) were compared to the values obtained when nasal cavity was reassigned to air (AXB_Air) under the dose-to-medium (Dm ) reporting mode of AXB. RESULTS: For dose calculated under AXB_Lung, the D98% , D2% , and Dmean of the PTV69.96 _Air Cavity (PTV of prescription dose 69.96 Gy overlapping with nasal cavity) were on average 16.1%, 1.6%, and 8.6% larger than that calculated under AXB_Air, respectively. Up to 19.5% difference in D98% , 3% difference in D2% , and 11.2% difference in Dmean were observed in the worst cases for PTV69.96 . Similar trend was observed for the PTV5940 _Air Cavity, in which the D98% , D2% , and Dmean calculated under AXB_Lung were on average 14.7%, 2.5%, and 10.2% larger than that calculated under AXB_Air, respectively. In the worst cases, the difference observed in D98% , D2% , and Dmean could be up to 17.7%, 4.5%, and 12.7%, respectively. CONCLUSIONS: Significant dose difference calculated by AXB between the material assignment of lung and air in nasal cavity for NPC cases might imply the possibility of underdosage to the PTVs that overlap with inhomogeneity. Therefore, attention should be put to ensure that accurate material assignment for dose calculation under AXB such that optimal dosage was given for tumor control.

Exploratory Study of NPC-0501 Trial: Optimal Cisplatin Dose of Concurrent and Induction/Adjuvant Chemotherapy for Locoregionally Advanced Nasopharyngeal Carcinoma.

PURPOSE: The current recommendation for patients with locoregionally advanced nasopharyngeal carcinoma (NPC) is cisplatin-based induction chemotherapy (IC) or adjuvant chemotherapy (AC) plus concurrent chemoradiotherapy (CRT). However, data on the optimal platinum doses for each phase of combined regimens are lacking. EXPERIMENTAL DESIGN: 742 patients with NPC in the NPC-0501 trial treated with CRT plus IC/AC and irradiated with intensity-modulated radiotherapy (IMRT) were analyzed. The optimal platinum dose to achieve the best overall survival (OS) in the concurrent and induction/adjuvant phases was studied. RESULTS: Evaluation of the whole series shows the optimal platinum dose was 160 mg/m2 in the concurrent and 260 mg/m2 in the induction/adjuvant phase. Repeating the analyses on 591 patients treated with cisplatin throughout (no replacement by carboplatin) confirmed the same results. The cohort with optimal platinum doses in both phases had better OS than the cohort suboptimal in both phases (stage III: 90% vs. 75%; stage IVA-B: 80% vs. 56%, at 5-year). Multivariable analyses confirmed optimal platinum doses in both phases versus suboptimal dose in each phase are significant independent factors for OS, with HR of 0.61 [95% confidence interval (CI), 0.41-0.91] and 0.67 (95% CI, 0.48-0.94), respectively. Treatment sequence was statistically insignificant after adjusting for platinum doses. CONCLUSIONS: Both concurrent and IC/AC are needed for locoregionally advanced NPC, even for patients irradiated by IMRT; the concurrent platinum dosage could be set at ≥160 mg/m2 when coupled with adequate induction/adjuvant dosage at ≥260 mg/m2 (or at least ≥240 mg/m2). To achieve these optimal dosages, IC-CRT at conventional fractionation is favored.

The radiobiological effect of using Acuros XB vs anisotropic analytical algorithm on hepatocellular carcinoma stereotactic body radiation therapy.

The purpose of this work was to study the radiobiological effect of using Acuros XB (AXB) vs Analytic Anisotropic Algorithm (AAA) on hepatocellular carcinoma (HCC) stereotactic body radiation therapy (SBRT). Seventy SBRT volumetric modulated arc therapy (VMAT) plans for HCC were calculated using AAA and AXB respectively with the same treatment parameters. Published tumor control probability (TCP) and normal tissue complication probability (NTCP) models were used to quantify the effect of dosimetric difference between AAA and AXB on TCP, NTCP and uncomplicated tumor control probability (UTCP). There was an average decrease of 2.5% in 6-month TCP. Normal liver has the largest average decrease in NTCP which was 59.7%. Bowels followed with 26.6% average decrease in NTCP. Duodenum, stomach and esophagus had 10.2%, 5.1%, and 4.3% average decrease in NTCP. There was an average decrease of 1.8% and up to 7.2% in 6-month UTCP. There was an overall decrease in TCP, NTCP, and UTCP for HCC SBRT plans calculated using AXB compared to AAA which could be clinically significant.

Opportunities and challenges in combining immunotherapy and radiotherapy in head and neck cancers.

Locally advanced and recurrent/ metastatic (R/M) head and neck cancers have poor prognosis generally. Radiotherapy (RT) is known to have multiple immunomodulatory effects, and various immune checkpoint inhibitors (ICIs) have been shown to be efficacious in the R/M setting in recent years. Hence, it is logical to combine RT and ICIs to improve the outlook for such patients, especially in view of the promising pre-clinical data on this novel combination. In this review, we highlighted the key mechanisms underlying the immunostimulatory and immunoinhibitory effects of RT, with a view to suggesting strategies to overcome radioresistance. We also discussed how the unique immune landscapes of virus-induced cancers, namely Epstein-Barr virus-induced nasopharyngeal carcinoma and human papillomavirus-mediated oropharyngeal cancer, could be exploited with ICIs. The landmark clinical trials in both the locally advanced and R/M settings were reviewed, and these trials showed that the combination of RT and ICIs is generally well tolerated. The potential reasons behind the largely negative results of these studies were also explored, focusing on various parameters including dose fractionation, sequencing, irradiated volume and the use of predictive biomarkers.

Shift detection discrepancy between ExacTrac Dynamic system and cone-beam computed tomography.

Accurate detection of patient shift is essential during radiation therapy such that optimal dose is delivered to the tumor while minimizing radiation to surrounding normal tissues. The shift detectability of a newly developed optical surface and thermal tracking system, which was known as ExacTrac Dynamic (EXTD), was evaluated by comparing its performance with the image guidance under cone-beam computed tomography (CBCT). Anthropomorphic cranial and pelvis phantoms with internal bone-like structures and external heat pad were utilized to study the shift detection discrepancy between EXTD system and CBCT. Random displacements within the range of ± 2 cm for translations and ± 2 degrees for rotations were intentionally applied to the phantom. Positional shifts detected by optical surface and thermal tracking (EXTD_Thml), stereoscopic X-ray (EXTD_Xray), and CBCT were compared in 6 degrees of freedom. The translational difference between EXTD_Thml and CBCT was 0.57 ± 0.41 mm and 0.66 ± 0.40 mm for cranial and pelvis phantom, respectively, while it was 0.60 ± 0.43 mm and 0.76 ± 0.49 mm between EXTD_Xray and CBCT, respectively. For rotational movement, the difference between EXTD_Thml and CBCT was 0.19 ± 0.16° and 0.19 ± 0.22° for cranial and pelvis phantom, respectively, while it was 0.13 ± 0.18° and 0.65 ± 0.46° between EXTD_Xray and CBCT, respectively. This study demonstrated that the EXTD system with thermal mapping ability could offer comparable accuracy for shift detection with CBCT on both cranial and pelvis phantoms.

Identifying optimal clinical trial candidates for locoregionally advanced nasopharyngeal carcinoma: Analysis of 9468 real-world cases and validation by two phase 3 multicentre, randomised controlled trial.

BACKGROUND AND PURPOSE: This study aims to identify the optimal high-risk candidates for clinical trials in locoregionally advanced nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Non-metastatic NPC patients (n = 9,468) were included. Recursive partitioning analyses (RPA) were performed to generate risk stratification. Receiver operating characteristics curve was used to determine the cut-off value of pre-treatment Epstein-Barr virus (EBV) DNA for progression-free survival (PFS). Individual-level data from two clinical trials were used for validation. RESULTS: Anatomic stratification based on T and N category (eighth edition TNM, TNM-8) classified the N2-3 or T4 as an anatomic high-risk group with 5-year PFS of 69% (95% confidence interval: 68-71%). Prognostic stratification identified patients with pre-treatment EBV DNA ≥4000 copies/mL as a prognostic high-risk group with 5-year PFS of 69% (67-70%). The c-index was significantly higher for anatomic stratification (0.621, p < 0.001) and prognostic stratification (0.585, p < 0.001) compared with existing TNM-8 stage groups (0.562). The validation cohorts based on clinical trials data showed greater PFS benefit than the results of the original trials [Hazard ratio: NCT01245959, 0.64 vs. 0.67; NCT01872962, 0.42 vs. 0.52]. Moreover, detectable post-treatment EBV DNA indicated a high risk of progression with 5-year PFS of 38.7% and was the most adverse independent factor for all endpoints. CONCLUSIONS: N2-3 or T4 NPC patients were ideal candidates for multicenter clinical trials in locoregionally advanced NPC. Patients with detectable post-treatment EBV DNA are suitable candidates for adjuvant trials.

Meta-analysis of chemotherapy in nasopharynx carcinoma (MAC-NPC): An update on 26 trials and 7080 patients.

PURPOSE: Chemotherapy, when added to radiotherapy, improves survival in locally advanced nasopharyngeal carcinoma (NPC). This article presents the second update of the Meta-Analysis of Chemotherapy in NPC. METHODS: Published or unpublished randomized trials assessing radiotherapy (±a second chemotherapy timing) with/without chemotherapy in non-metastatic NPC patients were identified. Updated data were sought for studies included in the previous rounds of the meta-analysis. The primary endpoint was overall survival. All trials were analyzed following the intent-to-treat principle using a fixed-effects model. Treatments were classified in five subsets according to chemotherapy timing. The statistical analysis plan was pre-specified. RESULTS: Eighteen new trials were identified. Individual patient data were available for seven. In total, the meta-analysis now included 26 trials and 7,080 patients. The addition of chemotherapy reduced the risk of death, with a hazard ratio (HR) of 0.79 (95% confidence interval (CI) [0.73; 0.85]), and an absolute survival increase at 5 and 10 years of 6.1% [+3.9; +8.3] and + 8.4% [+5.7; +11.1], respectively. The largest effect was observed for concomitant + adjuvant, induction (with concomitant in both arms) and concomitant chemotherapy, with respective HR [95%CI] of 0.68 [0.59; 0.79] (absolute survival increase at 5 years: 12.3% (7.0%;17.6%)), 0.73 [0.63; 0.86] (6.0% (2.5%;9.5%)) and 0.81 [0.70; 0.92] (5.2% (0.8%;9.6%)). The benefit of chemotherapy was also demonstrated by improvement in progression-free survival, cancer mortality, locoregional control and distant control. There was a significant interaction between patient age and chemotherapy effect. CONCLUSION: This updated meta-analysis confirms the benefit of concomitant chemotherapy and concomitant + adjuvant chemotherapy, and suggests that addition of induction or adjuvant chemotherapy to concomitant chemotherapy improves tumor control and survival. The benefit of chemotherapy decreases with increasing patient age.