[Comparing the prognostic value of 3 diagnostic criteria of bronchopulmonary dysplasia in preterm infants]

Objective: To compare the prognostic value of 3 diagnostic criteria of bronchopulmonary dysplasia (BPD) in preterm infants with gestational age<32 weeks. Methods: The retrospective cohort study was conducted to collect the clinical data of 285 preterm infants with BPD admitted to the Department of Neonatology, Children's Hospital Affiliated to Zhengzhou University from January 2019 to September 2021, who were followed up regularly after discharge. The primary composite adverse outcome was defined as death or severe respiratory morbidity from 36 weeks of corrected gestational age to 18 months of corrected age, and the secondary composite adverse outcome was defined as death or neurodevelopmental impairment. According to the primary or secondary composite adverse outcomes, the preterm infants were divided into the adverse prognosis group and the non-adverse prognosis group. The 2001 National Institute of Child Health and Human Development (NICHD) criteria, 2018 NICHD criteria, and 2019 Neonatal Research Network (NRN) criteria were used to diagnose and grade BPD in preterm infants. Chi-square test, Logistic regression analysis, receiver operating characteristic (ROC) curve and Delong test were used to analyze the prognostic value of the 3 diagnostic criteria. Results: The 285 preterm infants had a gestational age of 29.4 (28.1, 30.6) weeks and birth weight of 1 230 (1 000, 1 465) g, including 167 males (58.6%). Among 285 premature infants who completed follow-up, the primary composite adverse outcome occurred in 124 preterm infants (43.5%), and the secondary composite adverse outcome occurred in 40 preterm infants (14.0%). Multivariate Logistic regression analysis showed that severe BPD according to the 2001 NICHD criteria, gradeⅡand Ⅲ BPD according to the 2018 NICHD criteria and grade 2 and 3 BPD according to the 2019 NRN criteria were all risk factors for primary composite adverse outcomes (all P<0.05). ROC curve showed that the area under the curve (AUC) of the 2018 NICHD criteria and 2019 NRN criteria were both higher than that of the 2001 NICHD criteria (0.70 and 0.70 vs. 0.61, Z=4.49 and 3.35, both P<0.001), but there was no significant difference between the 2018 NICHD and 2019 NRN criteria (Z=0.38, P=0.702). Multivariate Logistic regression analysis showed that the secondary composite adverse outcomes were all associated with grade Ⅲ BPD according to the 2018 NICHD criteria and grade 3 BPD according to the 2019 NRN criteria (both P<0.05). ROC curve showed that the AUC of the 2018 NICHD criteria and 2019 NRN criteria were both higher than that of the 2001 NICHD criteria (0.71 and 0.71 vs. 0.58, Z=2.93 and 3.67, both P<0.001), but there was no statistically significant difference between the 2018 NICHD and 2019 NRN criteria (Z=0.02, P=0.984). Conclusion: The 2018 NICHD and 2019 NRN criteria demonstrate good and comparable predictive value for the primary and secondary composite adverse outcomes in preterm infants with BPD, surpassing the predictive efficacy of the 2001 NICHD criteria.

[Clinicopathological and molecular features of metaplastic thymoma]

Objective: To investigate the clinicopathological features, and molecular genetic alterations of metaplastic thymoma (MT). Methods: A total of ten MT cases, diagnosed from 2011 to 2021, were selected from the Department of Pathology of Jinling Hospital, Nanjing University Medical School, Nanjing, China for clinicopathological and immunohistochemical (IHC) examination and clinical follow-up. Fluorescence in situ hybridization (FISH), next-generation sequencing (NGS), and YAP1 C-terminus (YAP1-CT) IHC were performed to detect YAP1::MAML2 fusions. Results: There were four males and six females, ranging in age from 29 to 60 years (mean 50 years, median 54 years). Microscopically, all tumors showed a typical biphasic morphology consisting of epithelial components and gradually or abruptly transitioning spindle cell components. The two components were present in varying proportions in different cases. Immunophenotypically, the epithelial cells were diffusely positive for CKpan, CK5/6 and p63. The spindle cells were diffusely positive for vimentin and focally positive for EMA. TdT was negative in the background lymphocytes. Ki-67 proliferation index was less than 5%. YAP1 and MAML2 break-apart FISH analyses showed that all ten cases had narrow split signals with a distance of nearly 2 signal diameters and may be considered false-negative. Using YAP1::MAML2 fusion FISH assays, abnormal fusion signals were observed in all the ten cases. NGS demonstrated YAP1::MAML2 fusions in all eight cases with adequate nucleic acids; in two cases the fusions were detected by DNA sequencing and in eight cases by RNA sequencing. All ten cases of MT demonstrated loss of YAP1 C-terminal expression in epithelioid cells. Conclusions: MT is a rare and low-grade thymic tumor characterized by a biphasic pattern and YAP1::MAML2 fusions. Break-apart FISH assays may sometimes show false-negative results due to the proximity of YAP1 and MAML2, while YAP1 C-terminal IHC is a highly sensitive and specific marker for MT. Loss of YAP1 C-terminal expression can also be used to screen YAP1::MAML2 fusions for possible MT cases.

[Periodic dynamic observation and analysis of cellular and humoral immunity indexes of adults infected with Omicron BA.1]

Objective: To analyze the immunological characteristics and antibody changes of patients infected with the Omicron BA.1 and evaluate the possibility of secondary infection. Methods: A total of 104 patients infected with Omicron BA.1 in the Jinnan District of Tianjin from January 8 to February 2, 2022, were included in the study. The control group and case group were matched 1∶1 based on age, sex and vaccination status. Serum was collected from the case group and control group at 3, 6 and 9 months after infection. The serum levels of interleukin4 (IL-4), IL-5 and interferon-gamma (IFN-γ), as well as the positive rates of IgG, IgG1 and IgG2, were detected by ELISA. Results: The highest concentration of IFN-γ in the case group at 6 months after infection was 145.4 pg/ml, followed by a decrease in concentration. The concentrations of IL-4 and IL-5 began to decrease at 6 months after infection (all P<0.001). There was no significant difference in the IgG2 positive rate between the case group and the control group at 6 months after BA.1 infection. However, at 9 months, there was a significant decrease compared to the control group (P=0.003). The ratio of IFN-γ/IL4 at 3 months after infection in the case group was lower than that in the control group (P<0.001). There was no significant difference in the ratio between the case group and the control group at 9 months after infection. Conclusion: The cellular immune function has been impaired at 3 months after infection with BA.1, and the specific cellular immune and humoral immune functions decrease significantly after 6 months, and the risk of secondary infection increases.

HPV-positive clinically advanced squamous cell carcinoma of the urinary bladder (aBSCC): A comprehensive genomic profiling (CGP) study

BACKGROUND

Advanced bladder squamous cell carcinoma (aBSCC) is an uncommon form of urinary bladder malignancy when compared with the much higher urothelial carcinoma incidence. We studied the genomic alteration (GA) landscape in a series of aBSCC based on the association with human papilloma virus (HPV) to determine if differences in GA would be observed between the positive and negative groups.

METHODS

Using a hybrid capture-based FDA-approved CGP assay, a series of 171 aBSCC were sequenced to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. Programmed cell death ligand -1 (PD-L1) expression was determined by IHC (Dako 22C3) with negative expression when PD-L1 was 0, lower expression of positivity set at 1 to 49%, and higher expression set at ≥50% expression.

RESULTS

Overall, 11 (6.4%) of the aBSCC were found to harbor HPV sequences (10 HPV16 and 1 HPV 11). HPV+ status was identified slightly more often in women (NS) and in younger patients (P = 0.04); 2 female patients with aBSCC had a prior history of SCC including 1 anal SCC and 1 vaginal SCC. HPV+ aBSCC had fewer GA/tumor (P < 0.0001), more inactivating mutations in RB1 (P = 0.032), and fewer inactivating GA in CDKN2A (P < 0.0001), CDKN2B (P = 0.05), TERT promoter (P = 0.0004) and TP53 (P < 0.0001). GA in genes associated with urothelial carcinoma including FGFR2 and FGFR3 were similar in both HPV+ and HPV- aBSCC groups. MTAP loss (homozygous deletion) which has emerged as a biomarker for PRMT5 inhibitor-based clinical trials was not identified in any of the 11 HPV+ aBSCC cases, which was significantly lower than the 28% positive frequency of MTAP loss in the HPV- aBSCC group (P < 0.0001). MTOR and PIK3CA pathway GA were not significantly different in the 2 groups. Putative biomarkers associated with immunotherapy (IO) response, including MSI and TMB status, were also similar in the 2 groups. PD-L1 expression data was available for a subset of both HPV+ and HPV- cases and showed high frequencies of positive staining which was not different in the 2 groups.

CONCLUSIONS

HPV+ aBSCC tends to occur more often in younger patients. As reported in other HPV-associated squamous cell carcinomas, HPV+ aBSCC demonstrates significantly reduced frequencies of inactivating mutations in cell cycle regulatory genes with similar GA in MTOR and PIK3CA pathways. The implication of HPV in the pathogenesis of bladder cancer remains unknown but warrants further exploration and clinical validation.

[Study on the comparison of postoperative liver injury caused by hepatic arterial perfusion chemotherapy combined with targeted immunotherapy with hepatic arterial chemoembolization combined with targeted immunotherapy for intermediate-and advanced-stage liver cancer]

Objective: To compare the postoperative liver function injury condition in patients with intermediate-and advanced-stage hepatocellular carcinoma (HCC) treated with hepatic artery infusion chemotherapy (HAIC) and hepatic artery chemoembolization (TACE) combined with immune checkpoint inhibitors (ICIs) and multi-target tyrosine kinase inhibitors (TKIs). Methods: Patients with intermediate-and advanced-stage HCC who were admitted and treated with HAIC/TACE+ICIs+TKIs therapy at Nanfang Hospital of Southern Medical University from January 2019 to November 2021, with follow-up up to July 2023, were retrospectively enrolled. The results of liver function tests within one week before interventional surgery and on the first day after surgery were recorded. The degree of postoperative liver injury was graded according to the common terminology criteria for adverse events 5.0 (CTCAE 5.0). The treatment efficacy was evaluated according to RECIST 1.1 criteria. Measurement data were compared between groups using a t-test or a non-parametric rank sum test. Enumeration data were compared between the groups using the χ(2) test or Fisher's exact probability method. The survival condition differences were analyzed by the log-rank method. Results: This study included 82 and 77 cases in the HAIC and TACE groups. There were no statistically significant differences between the two groups of patients in terms of gender, age, physical condition score, number of tumors, presence or absence of liver cirrhosis, Child-Pugh grade, albumin-bilirubin (ALBI) grade, and combined ICIs and TKIs . The HAIC group had later tumor staging, a greater tumor burden, poorer liver reserve function, and a larger proportion of patients in stage C (81.7% vs. 63.6%), χ(2)=6.573, P = 0.01). There were 53 cases (64.6% vs. 32.5%) with a maximum tumor diameter of ≥ 10cm, χ(2)=16.441, P < 0.001), and more patients had a retention rate of ≥ 10% for indocyanine green (ICG) at 15 minutes (68.3% vs. 51.9%, P = 0.035). The postoperative incidence rate of increased levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin was significantly lower in the HAIC group than that in the TACE group (28.0% vs. 63.6%, χ(2)=20.298, P < 0.001, 54.9% vs. 85.7%, χ(2)=17.917, P < 0.001;40.2% vs. 55.8%, χ(2)=3.873, P = 0.049). The number of patients with postoperative ALBI grade 3 was significantly lower in the HAIC group than that in the TACE group (6.1% vs. 16.9%, χ(2)=4.601, P = 0.032). There was no statistically significant difference in the incidence rate of postoperative hypoalbuminemia, activated partial thromboplastin time, or increased international standardized ratio between the two groups of patients. There was no statistically significant difference in median progression-free survival (7.3 months vs. 8.2 months, P = 0.296) or median overall survival (16.5 months vs. 21.9 months, P = 0.678) between the two groups of patients. Conclusion: The incidence rate of postoperative liver injury is higher in patients with intermediate-and advanced-stage HCC treated with TACE combined with ICIs and TKIs than in patients with HAIC combined with ICIs and TKIs.

[Establishment of a patient-derived xenograft humanized mouse model for hepatoblastoma in children]

Objective: To establish a patient-derived xenograft (PDX) humanized mouse model for hepatoblastoma in children. In addition, compare the biological consistency between successfully modeled PDX tumors and primary tumors in children while comparing and analyzing the influence of PDX model modeling success as a key factor. Methods: A PDX tumor model was constructed from fresh tumor tissue samples from 39 children with hepatoblastoma. The tumor growth time and volume size were recorded in detail. Simultaneously, 39 children's data were collected for experimental and clinical analysis. The difference in tumorigenesis rate between different parameters was analyzed by χ (2) test (categorical variable). Continuous variables with a normal distribution were compared using the t-test. Results: After cell passage and pathological diagnosis, 21 cases of hepatoblastoma PDX models were successfully constructed, with a success rate of 53.8% (21/39). Tumor samples from each generation of successfully modeled PDX models had pathology results that were consistent with those of the corresponding primary tumors. The analysis of the key factors affecting the tumor formation rate of PDX revealed that the metastasis rate was more successful in primary tumors than in liver in situ tumors (7/8 vs. 14/31, P = 0.049). However, there was no significant difference between tumor formation rates and pathological subtypes. According to the PDX tumor formation group comparison between the primary tumor and the metastatic tumor, there was no statistically significant difference between the two groups in terms of tumor formation time and tumor volume. Hematoxylin-eosin staining in hepatoblastoma's PDX mouse was consistent with the primary tumor. Immunohistochemistry positivity rates of four proteins, namely hepatocyte antigen (Hepatocyte), phosphatidylinositol glycan 3, β-catenin, and alpha-fetoprotein, in primary tumor tissues and PDX mouse models were 100% vs. 100%, 100% vs. 95.24%, 100% vs. 100%, and 95.24% vs. 85.71%, respectively. Conclusion: A PDX mouse model for hepatoblastoma has been successfully established in children. The tumor formation rate is high, with metastatic tumors having a higher tumor formation rate than primary tumors and transplanted tumors retaining the biological characteristics of primary tumors.

A contemporary analysis of the pre- and intraoperative recognition of multigland parathyroid disease

BACKGROUND

Despite advances in biochemical and radiological identification of parathyroid gland enlargement, primary hyperparathyroidism (PHPT) due to sporadic multigland parathyroid disease (MGPD) remains a perioperative diagnostic dilemma. Failure to recognise MGPD pre- or intraoperatively may negatively impact surgical cure rates and result in persistent PHPT and ongoing patient morbidity.

METHODS

We have conducted a comprehensive review of published literature in attempt to determine factors that could aid in reliably diagnosing sporadic MGPD pre- or intraoperatively. We discuss preoperative clinical features and examine pre- and intraoperative biochemical and imaging findings concentrating on those areas that give practicing surgeons and the wider multi-disciplinary endocrine team indications that a patient has MGDP. This could alter surgical strategy.

CONCLUSION

Biochemistry can provide diagnosis of PHPT but cannot reliably discriminate parathyroid pathology. Histopathology can aid diagnosis between MGPD and adenoma, but histological appearance can overlap. Multiple negative imaging modalities indicate that MGPD may be more likely than a single parathyroid adenoma, but the gold standard for diagnosis is still intraoperative identification during BNE. MGPD remains a difficult disease to both diagnose and treat.

Coherent Subcycle Optical Shock from a Superluminal Plasma Wake

We propose exploiting the superluminal plasma wake for coherent Cherenkov radiation by injecting a relativistic electron beam (REB) into a plasma with a slowly varying density up-ramp. Using three-dimensional particle-in-cell and far-field time-domain radiation simulations, we show that an isolated subcycle pulse is coherently emitted towards the Cherenkov angle by bubble-sheath electrons successively at the rear of the REB-induced superluminal plasma wake. A theoretical model based on a superluminal current dipole has been developed to interpret such coherent radiation, and agrees well with the simulation results. This radiation has ultrashort attosecond-scale duration and high intensity, and exhibits excellent directionality with ultralow angular divergence and stable carrier envelope phase. Its intensity increases with the square of the propagation length and its central frequency can be easily tuned over a wide range, from the far infrared to the ultraviolet.

Granular vortex spin-torque nano oscillator for reservoir computing

In this paper, we investigate the granularity in the free layer of the magnetic tunnel junctions (MTJ) and its potential to function as a reservoir for reservoir computing where grains act as oscillatory neurons while the device is in the vortex state. The input of the reservoir is applied in the form of a magnetic field which can pin the vortex core into different grains of the device in the magnetic vortex state. The oscillation frequency and MTJ resistance vary across different grains in a non-linear fashion making them great candidates to be served as the reservoir's outputs for classification objectives. Hence, we propose an experimentally validated area-efficient single granular vortex spin-torque nano oscillator (GV-STNO) device in which pinning sites work as random reservoirs that can emulate neuronal functions. We harness the nonlinear oscillation frequency and resistance exhibited by the vortex core granular pinning of the GV-STNO reservoir computing system to demonstrate waveform classification.

Dosimetric Advantages of Online Adaptative Radiotherapy for Cervical Cancer on 1.5T MR-Linac

PURPOSE/OBJECTIVE(S)

Online adaptative radiotherapy (ART) strategy can be applied to account for inter-fraction organ motion while limiting organ at risk (OAR) dose. This study aims to evaluate tumor target and OARs inter- and intrafraction motion using online MRI during the full course of MR-Linac radiotherapy fractions. Furthermore, quantify the dosimetric consequences of online adaptative compared with non-adaptative radiotherapy (non-ART) in cervical cancer.

MATERIALS/METHODS

Six cervix cancer patients were treated with 150 fractions on the 1.5 T Unity MR-Linac. Each fraction, pre-treatment MRI scans were obtained at the start of every treatment session, and post-treatment MRI scans were obtained at the end of every treatment session. A total 300 MR images were included in this study and the CTV, bladder and rectum were delineated on each MRI by the same radiation oncologist. The inter-fraction and intrafraction changes of contours were evaluated by dice similarity coefficient (DSC), Hausdorff distance (HD), volume difference (ΔV). The reference treatment plans were generated using step-and-shoot IMRT and utilized 9 beam groups on original CT. Then, the online adaptative treatment plans were obtained by re-optimizing based on the contours on daily pre-treatment MRI by "adapt to shape" workflow using the same beam parameters and optimization objectives from the reference plans. Non-ART plans for each patient were generated by recalculating the dose from the reference plans on daily online MRI by "adapt to position" workflow. CTV coverage and OARs constraints were used to compare ART and non-ART plans.

RESULTS

The results showed that large inter-fraction anatomical changes limited the efficacy of radiation therapy (CTV: DSC: 0.89±0.03, HD: 20.83±5.05mm, ΔV: 1.21%±5.44%; Bladder: DSC: 0.68±0.18, HD: 30.58±15.75mm, ΔV: -10.17%±61.19%; Rectum: DSC: 0.69±0.09, HD: 22.98±12.03mm, ΔV: 21.01%±20.59%).The intrafraction anatomical changes were smaller (CTV: DSC: 0.96±0.01, HD: 8.85±3.54mm, ΔV: -0.64%±1.90%; Bladder: DSC: 0.90±0.07, HD: 14.62±9.56mm, ΔV: 19.83%±21.71%; Rectum: DSC: 0.98±0.04, HD: 2.90±4.27mm, ΔV: 0.13%±5.04%) . Non-ART showed inadequate primary CTV coverage in 30% of the daily fractions. Online adaptative plans improved CTV coverage significantly (p<0.001) to 99%. Compared with non-ART, online ART decreased the fraction dose to bladder and rectum indicated by significant (p<0.001) improvements for daily D50%, D2% and Dmean.

CONCLUSION

In cervical cancer radiotherapy, a non-adaptive strategy led to inadequate target coverage for individual patients. Online adaptative radiotherapy corrected for day-to-day anatomical variations and resulted in adequate target coverage in all fractions. The dose to rectum and bladder was decreased significantly when applying online adaptative radiotherapy.

Effect of Anemia on Tumor Response to Preoperative Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer

PURPOSE/OBJECTIVE(S)

Preoperative neoadjuvant chemoradiotherapy (nCRT) and total rectal mesenteric resection (TME) are the primary treatment options for locally advanced rectal cancer (LARC), but their efficacy varies. This study aimed to investigate the impact of anemia on the tumor response of patients with LARC receiving preoperative neoadjuvant chemoradiotherapy.

MATERIALS/METHODS

This study was a retrospective analysis of clinical and pathological data from patients with LARC who underwent nCRT and TME from January 2019 to May 2022 at a single institution. The tumor response was evaluated based on the tumor regression grade (TRG) and T-stage change of the primary tumor. Hemoglobin concentration was measured and graded to determine the presence of anemia. Anemia was categorized into four groups based on the hemoglobin levels: mild anemia (90-120 g/L), moderate anemia (60-90 g/L), severe anemia (30-60 g/L), and extreme anemia (less than 30 g/L). Finally, tumor response was quantified histologically using the AJCC 8th edition tumor regression grading system for rectal cancer and pre- and post-treatment T-grading.

RESULTS

A total of 88 patients with LARC who received nCRT and TME were included in the study, with 17 females and 71 males. Of these patients, 9 were moderately anemic and 37 were mildly anemic. The radiation therapy regimen was administered at a dose of 1.8-2 Gy per fraction, five times a week, for a total dose of 45-50.4 Gy. Capecitabine chemotherapy was also administered orally (825 mg/m2, twice a day) on the days of radiation therapy. Other chemotherapy regimens included XELOX and mFOLFOX6. The TRG was significantly different in anemic patients compared to non-anemic patients (P = 0.039). Only 2 out of 46 anemic patients (4%) showed an excellent response (TRG0), while 8 out of 42 non-anemic patients (19%) showed an excellent response (p = 0.043). There was also a significant difference in the incidence of anemia between cT3 and cT4 stages (p = 0.048), with 44% of cT3 patients and 67% of cT4 patients being anemic. The number of patients with poor response (TRG2-3) decreased as the degree of anemia decreased, but no significant difference was found. The incidence of TRG3 was 11% in patients with moderate anemia and 7% in non-anemic patients (P = 0.863). There was no significant difference in postoperative pathological T-stage between anemic and non-anemic patients. 89% of anemic patients had a pathological stage of ypT3 or less after chemoradiotherapy, while 95% of non-anemic patients did (P = 0.167). The pre- and post-treatment pathological staging did not significantly differ between anemic and non-anemic patients. 67% of anemic patients had descending tumors, while 59.5% of non-anemic patients had descending tumors (p = 0.509).

CONCLUSION

Patients with LARC who have normal hemoglobin concentrations during nCRT have better tumor regression compared to patients with anemia. Additionally, the incidence of anemia was higher among patients with advanced T-stage prior to treatment.

Inter-fractional Assessment during MR-guided Online Adaptive Radiotherapy for Glioblastoma

PURPOSE/OBJECTIVE(S)

Magnetic resonance image (MRI) guided radiation therapy has the potential to improve outcomes for glioblastoma by adapting to tumor changes during radiation therapy. This study aimed to assess the feasibility and potential benefits of MR-guided online adaptive radiotherapy (MRgOART) for patients with glioblastoma.

MATERIALS/METHODS

Twenty consecutive patients with glioblastoma were treated with MRgOART of 60 Gy in 30 fractions by the 1.5 T MR-Linac. The MRgOART fractions employed daily MR scans and the contours were utilized to create each adapted plan. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated on MRI of pre-treatment simulation (Fx0) and all fractions (Fx1, Fx2, Fx3 ... Fx30) to evaluate the inter-fractional changes. These changes were quantified using absolute/relative volume (∆V), Dice similarity coefficient (DSC) and Hausdorff distance (HD) metrics. The reference treatment plans were generated using step-and-shoot IMRT and utilized 7-9 beam groups on original CT. Before the treatment, a synthetic CT (sCT) quality assurance (QA) process was performed to assess the dose accuracy of bulk relative electron density (rED) assignment for online MRI based treatment plan in terms of gamma analysis, point dose comparison and dose volume histogram (DVH) parameters. Then, the online adaptative treatment plans were obtained by re-optimizing based on the contours on daily pre-treatment MRI by "adapt to shape" workflow. Non-adaptive plans for each patient were generated by recalculating the dose from the reference plans on daily online MRI by "adapt to position" workflow. GTV and CTV coverage and organ at risk (OAR) constraints were used to compare non-adaptive and adaptive plans.

RESULTS

For both criteria, the 1%/1mm (98.58%±0.15%) and 2%/2mm (99.88%±0.18%) gamma passing rate results were always clinically acceptable in sCT QA process. The differences on point dose and DVH parameters between the plans based on sCT and original CT were less than 1%. A total of 20 patients with 600 fractions were evaluated. The results showed that large inter-fractional changes for GTV limited the efficacy of radiation therapy (DSC: 0.78±0.08, HD: 20.94±3.64mm, ∆V: 2.92%±6.36%). The inter-fractional CTV changes were smaller (DSC: 0.91±0.04, HD: 15.31±3.09mm, ∆V: 1.41%±1.29%). GTV coverage of non-adaptive plans was below the prescribed coverage in 228/600 fractions (38%), with 90 (15%) failing by more than 10%. For CTV coverage of non-adaptive plans, the changes were less than 5%. Online adaptative plans improved GTV and CTV coverage significantly (p<0.001) to 99%. The adaptive plans also had lower dose to whole brain than non-adaptive plans (p<0.001).

CONCLUSION

Significant inter-fractional tumor changes could be found during radiotherapy in patients with glioblastoma treated by the 1.5 T MR-Linac. Daily MR-guided re-optimization of treatment plans corrected for day-to-day anatomical variations and resulted in adequate target coverage in all fractions.

Exploring the TRP channel superfamily: research hotspots and development trends from function to disease

OBJECTIVE

Transient receptor potential (TRP) channels are a superfamily of permeable cation channels activated by various mechanisms and play a role in nearly all types of sensory signal transduction. In academia, few have comprehensively discussed the research status of TRP channels. This study aims to summarize the knowledge structure and research hotspots of TRP channels using bibliometrics.

MATERIALS AND METHODS

TRP channel-related publications from 2003 to 2022 were searched in the Web of Science Core Collection (WoSCC) database. VOSviewer was used for the bibliometric analysis of the literature.

RESULTS

We included 12,242 articles from 102 countries, primarily from the United States, China, and Japan. Our research indicates that the number of publications related to TRP channels has increased annually from 2003 to 2022. The leading research institutions are KU Leuven, Harvard University, and the Chinese University of Hong Kong. The Journal of Biological Chemistry is the foremost in this field. The main research topics include the structure and function of TRP channels, their role in pathogenesis, and potential therapeutic strategies for diseases such as pain and respiratory diseases. Among these, "transient receptor potential vanilloid 1 (TRPV1)", "transient receptor potential ankyrin 1 (TRPA1)", "TRPV4", "pain", and "therapy" are emerging research hotspots.

CONCLUSIONS

This study offers a comprehensive summary of the current research status and development trends of TRP channels and pinpoints the research hotspots in this field. It not only aids individuals interested in TRP channel-related research in quickly gauging the trends but may also guide the future research directions of researchers.

Adaptive Auto-Segmentation for MRI-Guided Online Adaptive Radiotherapy of Cervical Carcinoma

PURPOSE/OBJECTIVE(S)

Accurate and efficient delineation of organs and targets on session images is critical in MRI-guided online adaptive radiotherapy (MRgOART). This study proposes a registration-guided deep learning image segmentation framework to assist online delineation of cervical carcinoma.

MATERIALS/METHODS

A total of 300 T2-weighted MR images were acquired for patients with cervical carcinoma treated by a 1.5T Unity MR-Linac. The CTV, bladder, rectum, pelvic bone and femoral joints were delineated on each MRI by the same radiation oncologist. To overcome these obstacles to online MRI segmentation, we propose a registration-guided DL (RgDL) segmentation framework that integrates image registration algorithms and DL segmentation models. Firstly, the DL segmentation model was trained using nnU-net. Then, for each treatment fraction, the deformable image registration (DIR) algorithm generates initial contours from previous treatment fraction, which were used as guidance by DL model to obtain the accurate current segmentation. The segmentation accuracy of alone DIR, DL and RgDL were evaluated by dice similarity coefficients (DSC) and other distance-based metrics.

RESULTS

Compared to the baseline approaches using the DIR and the DL alone, RgDL achieved a DSC of 91.12% on CTV, higher than DIR and DL alone by 15.54% and 10.13%. The DSC of RgDL were improved to 95.58%, 93.65%, 87.8% and 94.84% for bladder, pelvic bone, rectum and femoral joints, higher than DIR and DL alone by 9.61% on average.

CONCLUSION

The proposed adaptive auto-segmentation method can achieve accurate and efficient segmentation and potentially overcome these obstacles to MRgOART.

Priority list of potential endocrine-disrupting chemicals in food chemical contaminants: a docking study and in vitro/epidemiological evidence integration

Diet is an important exposure route of endocrine-disrupting chemicals (EDCs), but many unfiltered potential EDCs remain in food. The in silico prediction of EDCs is a popular method for preliminary screening. Potential EDCs in food were screened using Endocrine Disruptome, an open-source platform for inverse docking, to predict the binding probabilities of 587 food chemical contaminants with 18 human nuclear hormone receptor (NHR) conformations. In total, 25 contaminants were bound to multiple NHRs such as oestrogen receptor α/β and androgen receptor. These 25 compounds mainly include pesticides and per- and polyfluoroalkyl substances (PFASs). The prediction results were validated with the in vitro data. The structural features and the crucial amino acid residues of the four NHRs were also validated based on previous literature. The findings indicate that the screening has good prediction efficiency. In addition, the epidemic evidence about endocrine interference of PFASs in food on children was further validated through this screening. This study provides preliminary screening results for EDCs in food and a priority list for in vitro and in vivo research.

Dosimetric Analysis of CBCT-Based Weekly Online Adaptive Radiotherapy for Locally Advanced Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

Anatomic and geometric changes are common during a radiotherapy course amongst patients receiving conventional fractionated radiotherapy for locally advanced non-small cell lung cancer (LA-NSCLC). These changes may cause significant deviation from initial reference plan resulting in over-treatment of normal tissue or under-coverage of the target. Cone-beam computed tomography (CBCT)-based online adaptive radiotherapy (ART) platforms allow for response to these changes and is being increasingly used in the clinic though less so for intrathoracic disease. We hypothesized weekly CBCT-ART would improve target coverage and decrease dose to organs at risk (OAR) in patients with LA-NSCLC.

MATERIALS/METHODS

Data was collected from a prospective registry of 23 LA-NSCLC patients treated to 60 Gy in 30 fractions with CBCT-ART between June 2021 and December 2022. For weekly ART (Wk-ART), online plan adaptation started on week two. The adapted plan was then used to treat patients with image guidance until the next ART. For comparison, doses were recalculated with the initial reference plan on the SCT with updated contours to derive non-adapted (non-ART) dosimetry for each week. The final dosimetric parameters were obtained by averaging weekly coverage (ITV, PTV) and critical OAR (Lung, esophagus, heart, spinal cord) doses for non-ART and weekly ART treatments respectively for each patient. Paired student t-test was performed to compare the dosimetric parameters between non-ART and Wk-ART.

RESULTS

We observed an average 29% ± 19% (median: 26%) reduction in ITV volume through the radiotherapy course, with 48% (11/23) of patients showing >30% reduction. Most significant volume reductions (16%) were observed between the third and fourth adaptation. Weekly ART showed significant (p<1×10-3) improvements in ITV and PTV coverage, and showed improved clinically relevant lung, esophageal, cardiac, and lung dosimetry (Table 1), especially in the later stages of treatment when the tumor showed significant shrinkage. The average time from contour review to quality assurance completed is 8.5±1.2 min.

CONCLUSION

CBCT-ART provides robust ART plan quality and efficient workflow. There are significant improvements in target coverage and OAR sparing in LA-NSCLC treated with weekly CBCT-ART and these are driven by the significant volume reduction of the ITV throughout treatment course.

The Role of CT-Based Radiomics Nomogram in Differential Diagnosis of Immune Checkpoint Inhibitor-Related Pneumonitis from Radiation Pneumonitis for Patients with ESCC

PURPOSE/OBJECTIVE(S)

The combination of immunotherapy and chemoradiotherapy has widely used for patients with esophageal squamous cell carcinoma (ESCC) and induced treatment-related adverse effects, particularly immune checkpoint inhibitor-related pneumonitis (CIP) and radiation pneumonitis (RP). The aim of this study is to differentiate between CIP and RP by the CT radiomics and clinical or radiological parameters.

MATERIALS/METHODS

A total of 76 ESCC patients with pneumonitis were enrolled in this retrospective study and divided into training dataset (n = 53) and validation dataset (n = 23). A total of 837 radiomics features were extracted from regions of interest (ROIs) based on the lung parenchyma window of CT images. A radiomics signature was constructed on the basis of the predictive features by the least absolute shrinkage and selection operator (LASSO). A logistic regression was applied to develop radiomics nomogram. Receiver operating characteristics (ROC) curve and area under the curve (AUC) were applied to evaluate the performance of pneumonitis etiology identification.

RESULTS

No significant difference was detected between training dataset and validation dataset. The radiomics signature which was made up of four radiomics features shown a favorable performance on differentiating between CIP and RP with the α-binormal-based and empirical AUC = 0.831 and 0.843. Patients with RP had a close relationship with location (p = 0.003) and shape of lesions (p = 0.002). The nomogram that combined with radiomics signature and clinical factors improved the classifying performance on discrimination in the training dataset (AUCαbin = 0.963 and AUCemp = 0.964). The results were verified in the validation dataset with AUC = 0.967 and 0.964.

CONCLUSION

CT-based radiomics features have potential values for differentiating between patients with CIP and RP. Addition of bilateral changes and sharp border produced superior model performance on classifying, which could be a useful method to improve related clinical decision-making.

Influence of Eyes Movement on Lens Dose during MR-Guided Radiotherapy for Brain Tumor

PURPOSE/OBJECTIVE(S)

Modern radiotherapy techniques achieve highly conformal target doses while avoiding organs at risk such as lens. The magnitude of eyes movement and its influence on lens dose is unclear. The lens dose is relevant for cataract formation. This study aims to evaluate the movement-range of lens and its influence on dose distribution during MR-guided radiotherapy for brain cancer patients.

MATERIALS/METHODS

Fifty patients with brain cancer who were treated with MR-guided radiotherapy on 1.5 T MR-Linac were included in this study. All patients underwent a pre-treatment MRI and post-treatment MRI for each fraction. The eyes and lens were delineated on each MR image by a radiation oncologist. The reference treatment plans based original CT were recalculated on each MRI by "adapt to position" workflow. Then, we created planning risk volume (PRV) for lens by adding population margin and reoptimized the reference plans to evaluate the dose changes for lens. Inter-fraction and intrafraction variability for eyes and lens were evaluated with the Dice similarity coefficient (DSC), the Hausdorff distance (HD) and mean distance to agreement (MDA). Differences in daily dose (Dmax and Dmean) for eyes and lens were assessed.

RESULTS

A total of 300 MR images were analyzed in this study. The eyes motion was observed (minimum DSC: 0.57; maximum HD: 10.53; maximum MDA: 3.13). And the obvious lens motion also was found (minimum DSC: 0.01; maximum HD: 10.78; maximum MDA: 5.68). The maximum dose changes for eyes were up to 34.1% and the mean dose changes were up to 18.1%. The maximum dose changes for lens were up to 97.9% and the mean dose changes for eyes were up to 89%. When the reoptimized plans were generated by PRV lens, the dose changes were decreased nearly to 0.

CONCLUSION

Eyes movements in all radiotherapy fractions result in higher lens doses and potentially increase cataract formation rate. Adding margin expansions in treatment planning, to account for eyes motion, is the feasible approach to limit lens dose.

Development and Validation of a Questionnaire to Measure ICU Nurses' Knowledge, Attitudes, and Practices Related to Central Line Bloodstream Infection Practices

BACKGROUND

Currently, there is no instrument available to assess intensive care unit (ICU) nurses' knowledge, attitudes, and practices (KAP) of central line-associated bloodstream infection (CLABSI) prevention practices.

PURPOSE

To develop and validate a CLABSI questionnaire to measure ICU nurses' KAP (CLABSI-KAP-Q).

METHODS

Data were collected from 255 nurses at 4 hospitals in Gansu Province, China. Questions on the CLABSI-KAP-Q were generated through a review of the literature, interviews with nurses, and multiple rounds of content validity evaluation by experts. The validity and reliability of the CLABSI-KAP-Q were assessed with exploratory factor analysis, confirmatory factor analysis, internal consistency, and correlation coefficients.

RESULTS

The final version of the CLABSI-KAP-Q consisted of 32 items. The reliability was represented by a Cronbach α of 0.946, while the test-retest reliability was 0.945. The overall content validity was 0.95.

CONCLUSIONS

The CLABSI-KAP-Q is shown to be valid and reliable and recommended for use in clinical practice.

Incidence of Major Depression, Suicidal Ideation, and Mental Health Treatment Amongst Cancer Survivors

PURPOSE/OBJECTIVE(S)

Receiving a cancer diagnosis and undergoing subsequent treatments can result in a significant psychological burden for cancer patients. However, there is conflicting literature on the incidence of major depression in cancer patients compared to patients without cancer. The purpose of this study was to investigate and further clarify the incidence of major depression, associated treatments, and suicidal ideation in cancer survivors compared to a non-cancer cohort.

MATERIALS/METHODS

This is a retrospective, population-based study using survey responses from the National Survey on Drug Use and Health collected from January 2015 to December 2019. Survey data sets were queried for all respondents aged 18 years or older who provided a cancer history. Patients with a reported history of cancer ("cancer survivors") were further stratified by whether they reported a "recent" cancer diagnosis within the past 12 months. Survey responses were then evaluated for recent diagnoses of and treatments for major depressive disorder and suicidal ideation. Rates were compared between cancer survivors and participants without cancer using the Pearson χ2 test and multivariable logistic regression models, respectively.

RESULTS

Among the 212,411 survey respondents identified, 7,635 (3.6%) reported a cancer history, with 1,486 (0.7%) reporting a recent cancer history. The incidence of major depression was not different between cancer survivors and participants without cancer (9.3% vs. 9.2%; p = 0.762), though the incidence was slightly higher amongst recent cancer survivors (10.0% vs. 9.2%; p = 0.259). Among patients diagnosed with major depression, cancer survivors were significantly more likely to receive treatment for depression (78.6% vs. 60.3%, p<0.001), with 72.6% discussing depressive symptoms with a medical professional and 64.3% receiving prescription medication. Suicidal ideation was significantly lower among cancer survivors (5.1% vs. 6.2%, p<0.001) including recent survivors (5.0% vs. 6.2%, p<0.001). Suicidal ideation was higher in patients with underlying major depression in both cancer survivors and participants without cancer (30.6% vs. 35.6%, p = 0.015). On logistic regression, respondents with underlying depression receiving treatment were more likely to have suicidal ideation (OR: 1.49; p<0.001) while having a cancer diagnosis did not correlate with suicidal ideation (OR: 0.87; p = 0.869).

CONCLUSION

There was no significant overall difference in the incidences of major depression between cancer survivors and patients without cancer. However, one consideration is the under-diagnosis depression among cancer survivors. Symptoms of depression may be overlooked and mistakenly attributed to appropriate grief from a cancer diagnosis. Among patients diagnosed with major depression, cancer survivors were more likely to receive treatment for depression. These results highlight the importance of early depression assessment and treatment for cancer survivors.

An Analysis of Patients Treated with Stereotactic Body Radiotherapy for Metastatic Urinary Tract Tumors to Identify Predictors of Response

PURPOSE/OBJECTIVE(S)

To identify selection criteria linked to outcomes in patients treated with stereotactic body radiotherapy (SBRT) for metastatic tumors of the urinary tract (UT).

MATERIALS/METHODS

Single institution retrospective analysis of SBRT treated patients for oligometastatic/progressive UT tumors from 2006-2022. Charts were queried for M1 status at diagnosis or during disease course, treatment details (surgery, SBRT, systemic therapy), metabolic status (diabetes [DM], BMI) and outcomes. A linear quadratic formula was used to calculate the biologically effective dose (BED) using an α/β of 10 for tumor. Descriptive statistics portrayed the cohort, and analyses were done at patient and site level. Time-to-event analyses, including overall survival (OS) and progression-free survival (PFS) from SBRT, were assessed by the Kaplan-Meier method. Cox regression was used for univariable (UVA) and multivariable analyses (MVA) to identify predictors of outcomes.

RESULTS

A total of 35 patients were treated at 44 metastatic sites, including: bone (25%), node (36.4%), lung (20.5%), soft tissue (13.6%) and liver (4.5%). Most were male (74.3%) with a median age of 70 (range: 51-89), without DM (60%) having a median BMI of 29.8, and ECOG <2 (97.1%) at time of SBRT. Six (17.1%) patients were M1 at diagnosis. Of the 29 non-M1 patients, 86.2% received definitive local therapy (LT), 58.6% had at least T3/N+ disease, 75.8% received systemic therapy with a median of 2 agents (range: 1-6) prior to SBRT. Sixteen (45.7%) received immunotherapy (IO) with most receiving this before (75%) and after (56.2%) SBRT. Six patients had positive PD-L1 status (n = 10). The median RT dose, fractionation and BED was 40 Gy (range: 14-46), 5 fractions, and 72 (range: 28-132), respectively. At a median follow-up of 34.8, the median OS was 18.4 m (range: 9.3-27.4) with a 2-year OS of 35.9%. At patient level, 62.8% recurred after SBRT. The median PFS after SBRT was 5.3 m (range: 1.8-8.7) with a 2-yr PFS of 29.3%. Patient-level PFS was improved with LT (6.7 vs 1.4 m; p = 0.001) and DM (NR vs 2.9 m; p = 0.015), whereas improved OS was related with LT (18.9 vs 6.6 m; p = 0.03), DM (p = 0.04), ECOG (p = 0.004), and no relapse after SBRT (NR vs 9.8 m; p <0.001). Exposure to < 3 systemic agents prior to SBRT portended better PFS (6.7 vs 2.6 m; p = 0.04) without any impact by IO. At site level, 20.4% of sites had local relapse with 4 being the first event. Site was related with PFS (p = 0.009) with order of increased relapse risk being liver > bone > soft tissue > node > lung. No dosimetric feature was related with recurrence risk. On MVA, both DM (p = 0.02) and LT (p = 0.002) were predictive for PFS. Only recurrence after SBRT predicted for OS on MVA (HR: 6.7, 95% CI: 1.4-31; p = 0.014). In the IO subset, median PFS was 5.3 m and OS was 9.4 m, with no difference seen with IO-SBRT sequence or PDL1 status.

CONCLUSION

Optimized selection criteria for metastasis-directed therapy in patients with UT tumors is unclear, notably with IO. Future studies may benefit by assessing circulating tumor markers prior to SBRT.

Machine Learning and Explainable Artificial Intelligence to Predict Occult Pelvic Nodal Metastases in Prostate Cancer

PURPOSE/OBJECTIVE(S)

Determination of risk of occult pelvic lymph node involvement (LNI) in patients with cN0 prostate cancer is critical for determination of optimal treatment options. Though several nomograms exist, machine learning (ML) approaches might enable physicians to better assess individual risk by incorporating multiple clinical risk factors. Herein, we developed a ML model to predict occult LNI, and explained its composition using an explainable artificial intelligence (XAI) framework.

MATERIALS/METHODS

Patients with cN0 prostate adenocarcinoma diagnosed from 2018-2020 were identified in the National Cancer Database. The query was limited to patients with known clinical staging and biopsy results who did not receive neoadjuvant therapy prior to pelvic nodal examination. Occult LNI was defined as pN1 disease based on surgical evaluation, with a minimum of 10 nodes examined. Five ML models were trained to predict LNI. Variables incorporated into the model were age, core biopsy results, Gleason scores, preoperative prostate specific antigen (PSA), and clinical T-stage. Model performance, measured using area under the receiver operator characteristic curve (AUC) on a holdout testing dataset, was compared to multivariable logistic regression. The best-performing model was explained using SHapley Additive exPlanation (SHAP) values. To permit more clinically-meaningful statistical interpretation, using a novel approach SHAP values were converted into odds ratios (OR), confidence intervals (CI), and p-values.

RESULTS

A total of 23,131 patients met inclusion criteria; 2,676 (11.6%) had occult LNI. The Extreme Gradient Boosting model outperformed all other models with an AUC of 0.82 (95% CI: 0.78-0.86) compared to 0.80 (95% CI: 0.76-0.84) for logistic regression. Increasing PSA (OR: 1.031; p<0.001), number of positive biopsy cores (OR: 1.055; p<0.001), and percent positive biopsy cores (OR: 1.01; p<0.001) were all associated with increased risk of LNI. Based on observation of SHAP dependence plots, risk of LNI plateaued at PSA>20 ng/dL and >11 positive cores, while no plateau was observed for percent positive biopsy cores. Relative to T1c disease, patients with T3b were at highest risk of LNI (OR: 1.461; p = 0.003). Gleason score of 9 was associated with significant risk of LNI (Ref: Gleason 6; OR: 1.891; p<0.001). This was primarily driven by the primary Gleason score; primary Gleason 5 disease was associated with significant risk of LNI (Ref: Gleason 3; OR: 1.915; p<0.001) while a secondary Gleason score of 5 was the only grade with significant increased risk of LNI (Ref: Gleason 3; OR: 1.185; p = 0.004). Age and number of cores examined were not significant predictors of LNI.

CONCLUSION

Our ML achieved improved performance relative to logistic regression at predicting occult LNI. XAI provided insight into the inner-working of the ML model. ML can be used to identify patients at risk for occult LNI and therefore inform clinical decision-making.

Multidisciplinary Management of Primary Urethral Cancer with Radiotherapy

PURPOSE/OBJECTIVE(S)

Primary urethral cancer (PUC) is a rare form of genitourinary malignancy with a paucity of data to guide management. We analyzed PUC patients for clinicopathologic characteristics and treatment approach (radiotherapy [RT] with/without consolidative surgery) to identify predictors of outcome and RT response.

MATERIALS/METHODS

We conducted a single-institution retrospective review of patients treated with RT for PUC between 2002 to 2020. Each patient underwent multidisciplinary evaluation (including cystoscopy) as well as imaging to confirm tumor origin in the urethra. The linear quadratic formula was used to calculate the biologically effective dose (BED) using an α/β of 10 for tumor. Descriptive statistics were used to characterize the cohort. Fisher's Exact test was used to compare groups. Time-to-event analyses was conducted with the Kaplan-Meier method; outcomes included overall survival (OS) and time to recurrence (TTR) from diagnosis. Cox regression analysis assessed predictors of outcomes.

RESULTS

A total of 17 patients were identified for analysis. Median age was 63 years (range: 34-86); the majority were female (76.5%) and white (82.4%). Tumors were localized in the proximal (n = 6) or distal (n = 11) urethra. Histology included urothelial (11.8%), squamous (35.3%), adenocarcinoma (29.4%) and mixed (23.5%). Ten patients (58.8%) had cT3 or higher disease with 10 being cN0 (58.8%), 1 cN1 (5.9%), 5 cN2 (29.4%) and 1 cNx (5.9%). Median tumor size was 4.8 cm (range: 0.5-12 cm). The majority (88.2%) were treated with definitive chemoRT with 70.5% receiving platinum therapy. Median RT dose was 59.4 Gy (range: 39.6-70.2) with a median of 30 fractions. One patient underwent upfront cystourethrectomy and 6 (35.3%) underwent consolidative surgery at a median of 2.3 months after RT. Five patients (29.4%) had a complete response (CR) and 70.6% had a partial response (PR) to RT. Of the 7 patients who underwent surgical resection the final pathology was ypTis (28.5%), ypT1 (14.2%), ypT2 (14.2%), ypT4 (28.5%) and pT2 (14.2%). A median of 16 lymph nodes were removed with 1 patient having pN2 and all others pN0. Four patients (66.6%) were downstaged by chemoRT prior to surgery. At a median follow-up time of 8.4 years, the median OS was 37.9 months (range: 23.2-52.7), which was associated with a 5-year OS of 37.2%. Twelve (70.5%) patients recurred with a median TTR of 6.3 months (range 4.8-7.7). No demographics, staging methods, or tumor characteristics were associated with OS or TTR. Urothelial histology was associated with CR following chemoRT (p = 0.02). RT dose (continuous) was associated with OS (p = 0.018) as well as a BED (HR: 0.90, 95% CI: 0.84-0.97; p = 0.01). A BED > 55 Gy was associated with improved median OS (56.4 vs 9.13 months, p = 0.006).

CONCLUSION

Analysis of PUC patients treated with multimodal therapy found higher rates of CR in patients with urothelial histology and increased OS in patients treated with a BED > 55 Gy. Neoadjuvant chemoRT may downstage disease prior to surgical extirpation.

The Feasibility of Level Ib Sparing Intensity Modulated Radiation Therapy in Nasopharyngeal Carcinoma Patients with High-Risk Factors: Based on International Guideline

PURPOSE/OBJECTIVE(S)

In spite of the rarity of level Ib recurrence after intensity-modulated radiation therapy, the International Guideline (IG) provides the risk factors for prophylactic coverage. In practice, however, there are significant differences between institutions. The purpose of this study is to examine the feasibility of sparing level Ib IMRT in NPC patients with high-risk factors based on IG.

MATERIALS/METHODS

From January 2014 to October 2017, newly-diagnostic, non-metastatic NPC patients in our center were retrospectively reviewed. According to the risk factors of prophylactic level Ib coverage in patients with negative level Ib recommended by IG, the characteristics of pre-treatment MRI were analyzed. Four high-risk factors were identified: a. involvement of the structures that drain to level Ib as first echelon (FES), including anterior half of nasal cavity, oral cavity, b. involvement of submandibular gland (SMG), c. with radiologic extranodal extension (rENE) in level II LNs, or d. maximal axial diameter (MAD)≧2 cm in level II LNs. Patients with risk factors were divided into Cohort A (with risk factors a), Cohort B (with risk factor b, but without a), and Cohort C (only with risk factors c and/or d). Recurrence rates of level Ib and regional relapse-free survival (RRFS) rates were evaluated in different cohorts.

RESULTS

A total of 961 patients were finally included. Thirty-six cases (3.7%) presented with radiologically positive level Ib metastasis. For the other patients with negative Ib LNs, there were 18, 65, 421, and 444 cases classified as FES involvement, SMG involvement, level II LNs with rENE, and level II nodal with MAD ≧2 cm. Excluding overlap, a total of 571 patients with risk factors were divided into three groups: Cohort A (n = 18), Cohort B (n = 49) and Cohort C (n = 504). Nine patients (9/961, 0.94%) developed level Ib recurrence. Except for 1 patient with positive Ib LNs at diagnosis, 2 did not meet any of the risk factors, while the other six (6/9, 66.7%) met at least one risk factor. The rate of recurrence at neck level Ib was highest in Cohort A (11.1%, 2/18; Ib-sparing group: 0/10, 0.0% vs Ib-covering group: 2/8, 25.0%; P = 0.183). In Cohort B, no cases were found with level Ib recurrence (0.0%, 0/49). In Cohort C, the rates were rare (0.8%, 4/504) in both groups (0.7%, 2/276 vs 0.9%, 2/228; P > 0.999). Among the three Cohorts, there were no significant differences in 5-year RRFS between two groups, which were 90.0% vs 62.5% (p = 0.248), 90.9% vs 92.0% (p = 0.905), and 92.6% vs 90.1% (p = 0.445), respectively. Among patients with high-risk factors, the incidence of grade 3-4 late dry mouth symptom was higher in the level Ib-covering group (3.1% vs 7.5%, P = 0.033).

CONCLUSION

Level Ib sparing appears safe and feasible for NPC patients with negative level Ib LNs, even if combined with risk factors: SMG involvement, and/or level II with rENE, and/or level II MAD ≧2 cm. Level Ib-sparing irradiation reduces dry mouth symptoms compared with level Ib-irradiation.