Radiotherapy For Nasopharyngeal Carcinoma Research Articles

Segmentation of organs at risk in nasopharyngeal cancer for radiotherapy using a self-adaptive Unet network

To investigate the accuracy of automatic segmentation of organs at risk (OARs) in radiotherapy for nasopharyngeal carcinoma (NPC). The CT image data of 147 NPC patients with manual segmentation of the OARs were randomized into the training set (115 cases), validation set (12 cases), and the test set (20 cases). An improved network based on three-dimensional (3D) Unet was established (named as AUnet) and its efficiency was improved through end-to-end training. Organ size was introduced as a priori knowledge to improve the performance of the model in convolution kernel size design, which enabled the network to better extract the features of different organs of different sizes. The adaptive histogram equalization algorithm was used to preprocess the input CT images to facilitate contour recognition. The similarity evaluation indexes, including Dice Similarity Coefficient (DSC) and Hausdorff Distance (HD), were calculated to verify the validity of segmentation. DSC and HD of the test dataset were 0.86±0.02 and 4.0±2.0 mm, respectively. No significant difference was found between the results of AUnet and manual segmentation of the OARs (P > 0.05) except for the optic nerves and the optic chiasm. AUnet, an improved deep learning neural network, is capable of automatic segmentation of the OARs in radiotherapy for NPC based on CT images, and for most organs, the results are comparable to those of manual segmentation.

Comparative evaluation of treatment plan quality for a prototype biology-guided radiotherapy system in the treatment of nasopharyngeal carcinoma

We aimed to compare prototype treatment plans for a new biology-guided radiotherapy (BgRT) machine in its intensity-modulated radiation therapy (IMRT) mode with those using existing IMRT delivery techniques in treatment of nasopharyngeal carcinoma (NPC). We retrospectively selected ten previous NPC patients treated in 33 fractions according to the NRG-HN001 treatment protocol. Three treatment plans were generated for each patient: a helical tomotherapy (HT) plan with a 2.5-cm jaw, a volumetric modulated arc therapy (VMAT) plan using 2 to 4 6-MV arc fields, and a prototype IMRT plan for a new BgRT system which uses a 6-MV photon beam on a ring gantry that rotates at 60 rotations per minute with a couch that moves in small incremental steps. Treatment plans were compared using dosimetric parameters to planning target volumes (PTVs) and organs at risk (OARs) as specified by the NRG-HN001 protocol. Plans for the three modalities had comparable dose coverage, mean dose, and dose heterogeneity to the primary PTV, while the prototype IMRT plans had greater dose heterogeneity to the non-primary PTVs, with the average homogeneity index ranging from 1.28 to 1.50 in the prototype plans. Six of all the 7 OAR mean dose parameters were lower with statistical significance in the prototype plans compared to the HT and VMAT plans with the other mean dose parameter being comparable, and all the 18 OAR maximum dose parameters were comparable or lower with statistical significance in the prototype plans. The average left and right parotid mean doses in the prototype plans were 10.5 Gy and 10.4 Gy lower than those in the HT plans, respectively, and were 5.1 Gy and 5.2 Gy lower than those in the VMAT plans, respectively. Compared to that with the HT and VMAT plans, the treatment time was longer with statistical significance with the prototype IMRT plans. Based on dosimetric comparison of ten NPC cases, the prototype IMRT plans achieved comparable or better critical organ sparing compared to the HT and VMAT plans for definitive NPC radiotherapy. However, there was higher dose heterogeneity to non-primary targets and longer estimated treatment time with the prototype plans.

Endovascular Management of Intractable Nasopharyngeal Hemorrhage in Patients Irradiated for Nasopharyngeal Carcinoma: A Twelve-Year Experience.

PurposeTo evaluate the efficacy of endovascular treatment of intractable nasopharyngeal hemorrhage after radiotherapy for nasopharyngeal carcinoma (NPC) and report the relevant endovascular therapeutic experience.Patients and MethodsRecords of patients who underwent endovascular treatment for intractable nasopharyngeal hemorrhage after irradiation for NPC from January 2007 to December 2019 were reviewed. The demographics, endovascular therapeutic details, and clinical outcomes were analyzed.ResultsTwenty-four consecutive patients were included in this study. Nineteen patients underwent embolization of the bilateral internal maxillary arteries; one patient underwent embolization of the right internal maxillary artery and the left external carotid artery; one patient underwent embolization of the left internal maxillary artery and the right internal carotid artery, and the other three patients underwent embolization of the unilateral internal carotid artery. During a mean follow-up of 600.9 days (range, 2–1658 days), twenty patients showed no recurrence of bleeding; one patient died of hemorrhagic shock; one patient had recurrent bleeding, and angiography revealed a pseudoaneurysm in the right internal carotid artery, which was then embolized with spring coil after a 30-min occlusion test. Two patients had recurrent bleeding on 2.5 months and 29.9 months respectively after the endovascular treatment, and angiography showed hypervascularity supplied by the bilateral internal maxillary arteries and then was embolized with polyvinyl alcohol particles. The three patients who received re-interventions showed no re-bleeding until the last follow-up.ConclusionPseudoaneurysm and hypervascularity are the main angiographic characteristics of patients with intractable nasopharyngeal hemorrhage after radiotherapy for NPC, and endovascular treatment provides a safe and effective management approach.

PO-0834: Tumor regression during intensity-modulated radiotherapy of nasopharyngeal carcinoma

PO-0834: Tumor regression during intensity-modulated radiotherapy of nasopharyngeal carcinoma

Endostar Combined with Intensity-Modulated Radiotherapy in Low-Risk Local Advanced Nasopharyngeal Carcinoma: A Phase II, Randomized, Multicentric Clinical Trial

Background: A Phase II, randomized, prospective, multicentric trial (NCT02237924) was conducted to evaluate the efficacy and safety of Endostar plus radiotherapy in patients with low-risk local advanced nasopharyngeal carcinoma (NPC). Methods: From 09/2014 to 08/2016, patients with low-risk local advanced NPC were randomly treated with Endostar plus radiotherapy (ERT group, n=60) and concurrent chemoradiotherapy (CCRT group, n=60). Primary endpoint was the 5-year overall survival (OS) rate. The secondary endpoints were 3-year progression free survival (PFS) rate, OS rate, loco-regional recurrence free survival (LRRFS) rates and distance metastasis free survival (DMFS) rates. Findings: After a median follow-up of 47 months, 3-year OS rates were 93.2% and 79.3%, 3-year PFS rates were 89.8% and 70.6%, 3-year DMFS rates were 93.2% and 80.7%, in two groups, respectively (P 0.05). Moreover, the incidences of complications were significantly lower in ERT group. For short-term curative effects, CR rates were 70.0% and 60.0% for primary tumor, 73.3%and 65.0% for cervical lymph nodes, in two groups, respectively (P 0.05). Interpretation: OS, PFS, and DMFS rates can be improved, adverse events be reduced, with better tolerability, by Endostar plus radiotherapy, when compared to concurrent chemoradiotherapy for local advanced low-risk NPC. Trial Registration: (NCT02237924). Funding Statement: This work was supported by National Natural Science Foundation of China (No. 81760542), the Projects for Research and Development of Medical and Health Appropriate Technology of Guangxi Zhuang Autonomous Region (No. S2018087), the Key Research and Development Program of Guangxi (No. Guike AB18281003), Guangxi Medical University Training Program for Distinguished Young Scholars, and Medical Excellence Award Funded by the Creative Research Development Grant from the First Affiliated Hospital of Guangxi Medical University, “139” Program for high-level medical talents in Guangxi, Innovation Team of the First Affiliated Hospital of Guangxi Medical University. Guangxi Science and Technology Program Project (GK AD17129013), Simcere. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: This study was approved by the Ethics Committee of Guangxi Medical University. All procedures performed in the study involving human participants were in accordance with the ethical standards of the 1964 Helsinki declaration and its later amendments. Written informed consent was obtained from the patient and his/her immediate families.

Early Prediction of Parotid Glands Secretory Function Based on MRI-ADC Acquired during Radiotherapy for Nasopharyngeal Carcinoma: A Phase II Prospective Study

Radiation-induced xerostomia remains one of common side effects for radiotherapy (RT) of nasopharyngeal carcinoma (NPC) and severely affects the quality of life for the NPC patients. We aim to investigate the feasibility of predicting parotid glands secretory function based on the changes of apparent diffusion coefficient (ADC) map from diffusion weighted MRI (DWI) of bilateral parotid glands during RT for NPC patients and to analyze the correlations between the delivered radiation dose, volume reduction of parotid glands and the salivary secretary function. Seventy-five NPC patients treated with IMRT were enrolled in the study. DWI data were acquired on a 3.0T MRI system at pre-RT, the 5th and 15th fractions and immediately post-RT. The ADC maps were created in the ipsilateral (IP) and contralateral parotid gland (CP). Chewing stimulating tests were used to evaluate the saliva secretion. Pearson analysis was used to assess the correlation between ADC, delivered dose, volume reduction, and saliva secretion. Mean ADC increases and volume reductions in both parotid glands were observed during RT. These changes generally occurred in two stages. At the 5th fraction, with the average (± standard deviation) delivered doses of 5.11 ± 6.73Gy (IP) and 4.84±4.01Gy (CP), the average saliva secretions reduced from 2.35 ± 0.18g (pre-RT) to 2.25 ± 0.18g (5th fraction). During this first stage, the mean ADC increased significantly by 16.51 ± 14.82% (IP), 13.44 ± 10.87% (CP), while the volumes of parotid glands had minimal changes (IP: 23.42 ± 8.33cm3 vs 23.12 ± 8.11cm3, CP: 24.37 ± 9.13 cm3 vs 23.81 ± 9.07 cm3). The increased mean ADC had a positive correlation with the delivered dose (r1 = 0.57, r2 = 0.58) and negative correlation with the decreased saliva secretion (r1 = -0.57, r2 = -0.65). In the second stage (from the 5th fraction to post-RT), with the total mean delivered doses to the parotid glands of 27.64 ± 3.63 Gy (IP) and 26.13 ± 2.16 Gy (CP), the average saliva secretion decreased to 1.70 ± 0.14 g (15th fraction) and 1.34 ± 0.15 g (post-RT). The mean ADC increased by 40.38 ± 21.91% (IP), 40.06 ± 23.91% (CP) in this stage, while the volumes of parotid glands decreased by 41.20 ± 10.77% (IP), 39.18 ± 11.88% (CP). The radiation dose positively correlated to increased ADC, and negatively correlated to the volume reduction and decreased salivary secretion. During radiotherapy for NPC, the ADC values of parotid glands increase dramatically. The increase positively correlates to radiation dose, and negatively correlates to the volume reduction and salivary secretion decrease. The mean ADC increases at the 5th fraction even no volume change is observed, indicating that the ADC is more sensitive biomarker that may be used to predict xerostomia in an early stage during RT for NPC, leaving enough time to adapt the remaining treatment if necessary.

The Circadian Clock Gene BMAL1 Increases Nasopharyngeal Carcinoma Radiosensitivity Through Promoting ATM Pathway-mediated G2/M Phase Cell Cycle Arrest And Apoptosis

To investigate the role and mechanism of the circadian clock gene BMAL1 in regulating nasopharyngeal carcinoma (NPC) radiosensitivity The regulatory role of BMAL1 in NPC radiotherapy was investigated using 44 NPC patients and the NPC cell line CNE2 which was genetically engineered to overexpress or silence BMAL1 gene. Its correlation with NPC survival outcome was determined using immunohistochemistry and Kaplan-Meier survival curves. Infected CNE2 cells were divided into four groups: BMAL1 overexpression and control groups; and BMAL1 RNA interference (RNAi) and control groups; and their responses to different doses of radiotherapy were examined. In addition, the association between BMAL1 and the ATM/ATR pathway was determined using western blot and co-immunoprecipitation assays. The 5-year survival rates of the BMAL1 high expression group were significantly higher than that of the low expression groups (p<0.05). Moreover, the BMAL1 overexpression group showed higher tumor growth inhibition rate (p<0.001) and apoptotic rate (p = 0.004) after radiotherapy; a lower proportion of S phase cells (p<0.001) but higher proportion of G2/M phase cells (p = 0.001) after 24 h of 8Gy irradiation; reduced number of colonies (p = 0.042), and lower survival score (p = 0.037); and upregulation of ATM/ATR pathway proteins (p<0.05). The reverse results were observed for the RNAi group. Of note, co-immunoprecipitation revealed the interaction between BMAL1 and ATM. Our findings demonstrated the positive correlation between BMAL1 expression and NPC survival and suggest that BMAL1 promotes NPC radiosensitivity by controlling cell cycle distribution of NPC cells through the ATM pathway.

Hypothyroidism In Nasopharyngeal Carcinoma Patients After IMRT: Update Results Of A 5- Year Longitudinal Study

Hypothyroidism (HT) is a common long-term complication after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). The aim of this study is to investigate the incidence and risk factors for predicting HT among NPC patients. February 2012 to December 2014, 178 consecutive NPC patients (median 47 years; range 18-72 years) were included in the present study. All patients were treated with IMRT with or without chemotherapy. Serum thyroid function by measuring TSH (thyroid stimulating hormone) and FT4 (free thyroxine) was evaluated before and after IMRT regularly. The cumulative probability of thyroid dysfunction was estimated using Kaplan-Meier method. Cox proportional hazard models with univariate and multivariate analyses were carried out to examine which clinical and dosimetric parameters were associated with the development of HT. The median follow-up was 61.6 months (range: 29.9-89.5 months). Of the 178 patients, 82 (46.1%) developed radiation-induced HT. Of the 82 patients, 76 were diagnosed with primary HT, 4 with central HT and 2 with a mixture of both primary and central HT. The 3- and 5- year actuarial risks of HT were 42.1% and 52.4%, respectively. The cumulative incidence of HT found in our study is generally compatible with a time-dependent effect, but it reached a plateau at 5 years following treatment. The median clinical latency for central HT was much longer than that for primary HT (15.8months vs 26.8months), but it didn’t reach statistical significance (p = 0.096). Smaller thyroid volume was identified to be an independent predictive factor for HT in both univariate and multivariate analyses (p = 0.000). A clear dose-dependent risk of HT was established in all the four multivariate models: Dtmean (p = 0.001), V40 (p = 0.014), V45 (p = 0.000) and V50 (p = 0.002) of the thyroid were all significant variables. The V50 multivariate model revealed that patients with thyroid V50 above 0.3 had a relative risk of HT that was 4.2 times the risk in those with V50 below 0.3. None of the dosimetric parameters related to pituitary gland reach statistical significance. Primary HT occurs fairly commonly after irradiation to the neck, whereas central HT is considered less common following IMRT for NPC. Dtmean and V50 were most predictive of the development of HT. Dtmean<45Gy and V50 < 0.3 should be recommended as the useful dose constraints during plan optimization.

MR-based Synthetic CT Images Generated Using Generative Adversarial Networks for Nasopharyngeal Carcinoma Radiotherapy Treatment Planning

MR-based Synthetic CT Images Generated Using Generative Adversarial Networks for Nasopharyngeal Carcinoma Radiotherapy Treatment Planning

Narrative review: temporal lobe necrosis after radiotherapy for nasopharyngeal carcinoma

Narrative review: temporal lobe necrosis after radiotherapy for nasopharyngeal carcinoma

A New Model for Predicting Hypothyroidism After Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma.

ObjectivesTo develop a model that can predict the risk of hypothyroidism (HT) after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC), and to accordingly recommend dose constraints.Materials and MethodsNPC patients treated between 2011 and 2015 were retrospectively reviewed. HT was defined by an abnormally high level of thyrotropin. The dosimetry parameters Vx (percentage of thyroid volume receiving more than x Gy of radiation) and Va,b (percentage of thyroid volume receiving >a Gy, while ≤b Gy radiation) were calculated. The primary endpoint was the development of HT within the first 2 years after IMRT. The least absolute shrinkage and selection operator and multivariate logistic regression were used to identify predictors of HT.ResultsA total of 545 patients were included in the analyses, with a median follow-up of 36 months. Of the 545 patients, 138 developed HT within 2 years, and the 2-year incidence of HT was 25.3%. In patients with thyroid volume >20 cm3, the 2-year incidence of HT was 11.7% (16/137); in patients with thyroid volume ≤20 cm3 and V30,60 ≤ 80%, the 2-year HT incidence was 19.9% (33/166); in patients with thyroid volume ≤20 cm3 and V30,60 > 80%, the 2-year incidence of HT was 36.8% (89/242).ConclusionThyroid volume and V30,60 could be reliable predictors of HT after IMRT for NPC. For patients with thyroid volume ≤20 cm3, thyroid V30,60 ≤ 80% might be a useful dose constraint to adopt during IMRT planning.

Second primary cancer after intensity-modulated radiotherapy for nasopharyngeal carcinoma: A territory-wide study by HKNPCSG.

Long-term risk of second primary cancer (SPC) after definitive intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) remains unclear. This study aims to evaluate the risk, predictive factors and survival impact of SPC in a large territory-wide cohort of NPC survivors in an endemic region. In this multicenter study, consecutive NPC patients (n = 3166) who underwent definitive IMRT in all six public oncology centers in Hong Kong between 2001 and 2010 were included. SPC risks were quantified by standardized incidence ratios (SIRs) and absolute excess risks (AERs) estimated from corresponding age-, sex-, and calendar year-specific population cancer incidence data from the Hong Kong Cancer Registry. Predictive factors and SPC-specific mortality were analyzed. Over a median follow-up period of 10.8 years, 290 cases of SPC were observed with a crude incidence of 9.2%. Cancer risk in NPC survivors was 90% higher than that in general population [SIR, 1.9; 95% confidence interval (CI), 1.7-2.2], with an AER of 52.1 (95% CI, 36.8-67.3) per 10,000 person-years at risk. Significant excess cancer risks were observed for oral cavity, sarcoma, oropharynx, paranasal sinus, salivary gland, thyroid, skin and lung. Advanced age, smoking, hepatitis B status, and re-irradiation were independent predictive factors. SPC accounted for 9.4% of all deaths among NPC survivors during the study period, and 10-year SPC-specific mortality was 3.4%. Second cancer risk after IMRT was substantial among NPC patients. SPC impairs long-term survival, and close surveillance is warranted as part of survivorship care.

FANCD2 knockdown with shRNA interference enhances the ionizing radiation sensitivity of nasopharyngeal carcinoma CNE-2 cells.

Fanconi anemia complementation group D2 (FANCD2) has been associated with the sensitivity of tumor cells to DNA crosslinking damaging agents in certain solid tumors. However, its role in nasopharyngeal carcinoma (NPC) is still unclear. In the present study, the role of FANCD2 in the response of NPC CNE-2 cells to radiation was investigated. A CNE-2 cell model with stable FANCD2 silencing was constructed by lentiviral transfection. Fluorescence quantitative PCR and western blotting were used to evaluate FANCD2 expression in CNE-2 cells. The biological impact of FANCD2 silencing on the response of CNE-2 cells to radiation was investigated in vitro and in vivo. The microarray technology, western blotting, and immunohistochemistry were used to analyze the proteins involved in related pathways after irradiation to investigate the underlying mechanism. Lentivirus-mediated shRNA interference stably silenced the FANCD2 gene in CNE-2 cells. In vitro, in the FANCD2-silenced group, cell proliferation was significantly inhibited, apoptosis was increased, and the cell cycle was arrested at the G2/M phase after irradiation. In vivo, FANCD2 silencing slowed tumor growth, as the volume and weight of the xenograft tumors were significantly decreased. Both in vitro and in vivo, the differentially expressed genes NUPR1, FLI1, and FGF21 were downregulated in the FANCD2-silenced group. Our results show that FANCD2 silencing affected the sensitivity of CNE-2 cells to ionizing radiation by regulating cell proliferation, apoptosis, and cell cycle distribution. The mechanism might be associated with changes in NUPR1, FLI1, and FGF21 protein expression due to the FANCD2 silencing. This study provides a promising target for NPC radiotherapy.

Efficacy of balloon dilatation of the eustachian tube in patients with refractory otitis media with effusion after radiotherapy for nasopharyngeal carcinoma.

To investigate the efficacy of balloon dilatation of the eustachian tube (BDET) in patients with refractory otitis media with effusion (OME) after radiotherapy for nasopharyngeal carcinoma. A total of 58 patients (74 ears) who had received BDET for treatment of refractory OME after radiotherapy for nasopharyngeal carcinoma were enrolled. The efficacy was evaluated by seven-item eustachian tube scores (ETS-7), tympanogram type and air-bone gap, and the total effective rate was also calculated. All patients were followed up for 2years. ETS-7 scores at every postoperative visit were significantly higher than preoperative scores (all P<0.05). ETS-7 score 6months after surgery was the highest, which declined sharply from the 6th to the 24th month after surgery. Air-bone gap from the 1st to the 18th month after surgery was significantly smaller than preoperative one (all P<0.05). Air-bone gap 6months after surgery was the smallest, followed by that 12months after surgery. The improvement in tympanogram type 6months after surgery was the highest. The improvement of tympanogram type declined sharply from 12 to 24months after surgery. According to evaluation of efficacy, only one patient completely recovered, and five patients partially recovered during the 2-year follow-up. BDET can only significantly improve efficacy of refractory OME after radiotherapy for nasopharyngeal carcinoma for a certain period of time during the 2-year follow-up.

Echo-Tracking Technique in Ultrasonography Can Monitor Changes in Carotid Artery Elastic Function at Early Stage of Intensity-Modulated Radiation Therapy for Nasopharyngeal Carcinoma.

BackgroundWe used echo-tracking (ET) technique to observe short-term dynamic changes of the carotid artery in nasopharyngeal carcinoma (NPC) patients after intensity-modulated radiation therapy (IMRT).Material/MethodsSixty-one NPC patients received IMRT. In the irradiation group, the carotid artery was examined by ultrasonography before radiotherapy, at 2, 4, and 6 weeks after the start of radiotherapy, and at 3 and 6 months after the end of radiotherapy. In the control group, the carotid artery was examined by ultrasonography before radiotherapy of patients in the irradiation group, and at 3 and 6 months after the end of radiotherapy of patients in the irradiation group.ResultsDuring radiotherapy for the 61 patients, the maximum dose on the carotid artery was 65.14±4.35 Gy, the average dose was 57.46±4.12 Gy, and the 50% volume dose was 51.80±5.32 Gy. At the end of irradiation, Ep (kPa) and β values were significantly different from those before treatment.ConclusionsThe present study demonstrates that the elastic function of the carotid artery can be significantly affected when the irradiation dose exceeds 45 Gy.

A longitudinal study on parotid and submandibular gland changes assessed by magnetic resonance imaging and ultrasonography in post-radiotherapy nasopharyngeal cancer patients.

Objectives:With regard to the intensity modulated radiotherapy (IMRT) of nasopharyngeal carcinoma (NPC) patients, this longitudinal study evaluated the radiation-induced changes in the parotid and submandibular glands in terms of gland size, echogenicity and haemodynamic parameters.Methods:21 NPC patients treated by IMRT underwent MRI and ultrasound scans before radiotherapy, and at 6, 12, 18 and 24 months after treatment. Parotid and submandibular gland volumes were measured from the MRI images, whereas the parotid echogenicity and haemodynamic parameters including the resistive index, pulsatility index, peak systolic velocity and end diastolic velocity were evaluated by ultrasonography. Trend lines were plotted to show the pattern of changes. The correlations of gland doses and the post-RT changes were also studied.Results:The volume of the parotid and submandibular glands demonstrated a significant drop from pre-RT to 6 months post-RT. The parotid gland changed from hyperechoic before RT to either isoechoic or hypoechoic after treatment. The resistive index and pulsatility index decreased from pre-RT to 6 month post-RT, then started to increase at 12 month time interval. Both peak systolic velocity and end diastolic velocity increased after 6 months post-RT then followed a decreasing trend up to 24 months post-RT. There was mild correlation between post-RT gland dose and gland volume, but not with haemodynamic changes.Conclusions:Radiation from IMRT caused shrinkage of parotid and submandibular glands in NPC patients. It also changed the echogenicity and vascular condition of the parotid gland. The most significant changes were observed at 6 months after radiotherapy.Advances in knowledge:It is the first paper that reports on the longitudinal changes of salivary gland volume, echogenicity and haemodynamic parameters altogether in NPC patients after radiotherapy. The results are useful for the prediction of glandular changes that is associated with xerostomia, which help to provide timely management of the complication when the patients attend follow-up visits.

Cervical spine osteoradionecrosis or bone metastasis after radiotherapy for nasopharyngeal carcinoma? The MRI-based radiomics for characterization

BackgroundTo develop and validate an MRI-based radiomics nomogram for differentiation of cervical spine ORN from metastasis after radiotherapy (RT) in nasopharyngeal carcinoma (NPC).MethodsA radiomics nomogram was developed in a training set that comprised 46 NPC patients after RT with 95 cervical spine lesions (ORN, n = 51; metastasis, n = 44), and data were gathered from January 2008 to December 2012. 279 radiomics features were extracted from the axial contrast-enhanced T1-weighted image (CE-T1WI). A radiomics signature was created by using the least absolute shrinkage and selection operator (LASSO) algorithm. A nomogram model was developed based on the radiomics scores. The performance of the nomogram was determined in terms of its discrimination, calibration, and clinical utility. An independent validation set contained 25 consecutive patients with 47 lesions (ORN, n = 25; metastasis, n = 22) from January 2013 to December 2015.ResultsThe radiomics signature that comprised eight selected features was significantly associated with the differentiation of cervical spine ORN and metastasis. The nomogram model demonstrated good calibration and discrimination in the training set [AUC, 0.725; 95% confidence interval (CI), 0.622–0.828] and the validation set (AUC, 0.720; 95% CI, 0.573–0.867). The decision curve analysis indicated that the radiomics nomogram was clinically useful.ConclusionsMRI-based radiomics nomogram shows potential value to differentiate cervical spine ORN from metastasis after RT in NPC.

913MO Second primary cancer after intensity-modulated radiotherapy for nasopharyngeal carcinoma in Hong Kong (2001-2010): A territory-wide study by HKNPCSG

913MO Second primary cancer after intensity-modulated radiotherapy for nasopharyngeal carcinoma in Hong Kong (2001-2010): A territory-wide study by HKNPCSG

Clinical Characteristics and Prognostic Factors of Early and Late Recurrence After Definitive Radiotherapy for Nasopharyngeal Carcinoma.

We investigated the clinical characteristics, prognostic factors, and post-recurrence prognostic factors of early- and late-recurrence patients for nasopharyngeal carcinoma (NPC) after definitive intensity-modulated radiation therapy (IMRT). This was a single-center retrospective analysis of patients in China from January 2010 to December 2015. The prognostic factors for overall survival (OS) and post-recurrence OS of early- and late-recurrence patients were identified using univariate and multivariate Cox regression analyses. Of the 9,468 patients included, 409 (4.3%), 325 (3.4%), and 182(1.9%) developed purely local recurrence, purely regional recurrence, and locoregional recurrence during follow-up, respectively. In the purely local recurrence group, 192 patients (46.9%) developed early local recurrence (ETR), and 217 patients (53.1%) developed late local recurrence (LTR). Of the 192 ETR patients, multivariate Cox regression analysis revealed that age and gender were independent risk factors of OS, and post-recurrence best supportive treatment (PRBST) was associated with poorer post-recurrence OS. Of the 217 LTR patients, the results revealed that baseline value of EBV-DNA was an independent risk factor for OS, while PRBST was associated with poorer post-recurrence OS. In the purely regional recurrence group, 183 patients (56.3%) developed early regional recurrence (ENR), and 142 patients (43.7%) developed late regional recurrence (LNR). Of the 183 ENR patients, multivariate Cox regression analysis revealed that alcohol abuse and TNM stage were independent risk factors of OS, while alcohol drinkers and PRBST were associated with poorer post-recurrence OS. Of the 142 LNR patients, PRBST was associated with poorer post-recurrence OS. In the locoregional recurrence group, 87 patients (47.8%) developed early locoregional recurrence (ELR), and 95 patients (52.2%) developed late locoregional recurrence (LLR). Of the 87 ELR patients, multivariate Cox regression analysis revealed that N stage and TNM stage were independent risk factors of OS, and N2/3 stage and PRBST were associated with poorer post-recurrence OS. Of the 95 LLR patients, the results revealed that T stage was an independent risk factor for OS, while T3/4 stage and PRBST were associated with poorer post-recurrence OS. Patients with LTR/LNR/LLR demonstrate significantly better OS compared with patients with ETR/ENR/ELR, Nevertheless, post-recurrence OS between patients with ETR/ENR/ELR and LTR/LNR/LLR was not significantly different.

Application of hypoglossal nerve constraint in definitive radiotherapy for nasopharyngeal carcinoma: A dosimetric feasibility study

Purpose: Radiation-induced hypoglossal nerve palsy is an infrequent but debilitating late complication after definitive radiotherapy for head and neck cancers. D1cc < 74 Gy (equivalent dose in 2 Gy fractions, EQD2) has been proposed as a potential dose constraint that limits 8-year palsy risk to < 5%. This study sets to perform detailed dosimetric assessments on the applicability of this novel dose constraint in advanced nasopharyngeal carcinoma (NPC). Materials and methods: This is a retrospective single-institution dosimetry study. NPC radiotherapy plans were identified from an institutional database, with an aim to select 10 eligible cases. Bilateral hypoglossal nerves were retrospectively contoured following a standard atlas. Cases with either one, or both, hypoglossal nerves D1cc exceeded 74 Gy EQD2 were included. Dosimetry of hypoglossal nerves, planning target volumes (PTV) and normal structures before and after application of the new hypoglossal nerve constraint were compared and analyzed. Results: Ten NPC cases were replanned. All hypoglossal nerve contours overlapped with high-dose PTV, predominantly at regions of gross nodal diseases. D1cc in 15 out of 20 hypoglossal nerves exceeded 74G y EQD2 at initial plans. All nerves fulfilled the pre-specified constraint of 74Gy EQD2 after re-plan. Median hypoglossal nerve D1cc reduced from 74.8Gy (range, 74.1 to 77.4Gy) to 73.5Gy (range, 72.4 to 74.0Gy) (p < 0.001), corresponded to a projected reduction in 8-year palsy risk from 5%-14% to 3%-5%. PTV V100 was maintained above 95% in all cases. Dose increments in near-maximum (D2) and decrements in near-minimum (D98) were < 1 Gy. Safety dosimetric parameters of standard head and neck organs-at-risk showed no significant changes. Conclusions: Hypoglossal nerve D1cc < 74 Gy EQD2 is a dosimetrically feasible constraint in definitive radiotherapy for NPC. Tumor target coverage and normal organ dosimetry were not compromised with its usage. Its routine application should be considered in definitive radiotherapy for head and neck cancers.