Prognostic value of lymph node-to-primary tumor ratio of PET standardized uptake value for nasopharyngeal carcinoma: a recursive partitioning risk stratification analysis.

Background: Induction chemotherapy (IC) combined with concurrent chemoradiotherapy has become the standard treatment for locoregionally advanced nasopharyngeal carcinoma (LA-NPC). Data on the prognostic value of the lymph node-to-primary tumor ratio (NTR) of positron emission tomography (PET) standardized uptake value (SUV) for patients treated with IC were limited. Objectives: To evaluate the prognostic value of the SUV NTR for patients with LA-NPC treated with IC. Design: In all, 467 patients with pretreatment 18F-fluorodeoxyglucose PET/computed tomography (CT) scans between September 2017 and November 2020 were retrospectively reviewed. Methods: The receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off value of SUV NTR. Kaplan-Meier method was used to evaluate survival rates. The recursive partitioning analysis (RPA) was performed to construct a risk stratification model. Results: The optimal cutoff value of SUV NTR was 0.74. Multivariate analyses showed that SUV NTR and overall stage were independent predictors for distant metastasis-free survival (DMFS) and regional recurrent-free survival (RRFS). Therefore, an RPA model based on the endpoint of DMFS was generated and categorized the patients into three distinct risk groups: RPA I (low risk: SUV NTR < 0.74 and stage III), RPA II (medium risk: SUV NTR < 0.74 and stage IVa, or SUV NTR ⩾ 0.74 and stage III), and RPA III (high risk: SUV NTR ⩾ 0.74 and stage IVa), with a 3-year DMFS of 98.9%, 93.4%, and 84.2%, respectively. ROC analysis showed that the RPA model had superior predictive efficacy than the SUV NTR or overall stage alone. Conclusion: SUV NTR was an independent prognosticator for distant metastasis and regional recurrence in locoregionally advanced NPC. The RPA risk stratification model based on SUV NTR provides improved DMFS and RRFS prediction over the eighth edition of the TNM (Tumor Node Metastasis) staging system.

Radiation-induced nasopharyngeal ulcers after re-irradiation with intensity-modulated radiotherapy in locoregional recurrent nasopharyngeal carcinoma patients: a dose-volume-outcome analysis.

OBJECTIVE: To analyze the interrelation between radiation dose and radiation-induced nasopharyngeal ulcer (RINU) in locoregional recurrent nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). METHODS: Clinical data were collected from 363 patients with locoregional recurrent NPC who received re-irradiated with definitive IMRT from 2009 to 2017. Twenty-nine patients were diagnosed with RINU. Univariate and multivariate analyses were used to re-evaluate the first and second radiotherapy plans and to identify predictive dosimetric factors. RESULTS: All dosimetric parameters were notably associated with the progression to RINU (p < 0.01) using paired samples Wilcoxon signed rank tests. Multivariate analysis showed that EQD2_ [Formula: see text]D80 (dose for 80 percent volume of the unilateral nasopharynx lesion) was an independent prognostic factor for RINU (p = 0.001). The area under the ROC curve for EQD2_ [Formula: see text]D80 was 0.846 (p < 0.001), and the cutoff point of 137.035 Gy could potentially be the dose tolerance of the nasopharyngeal mucosa. CONCLUSIONS: The sum of equivalent dose in 2 Gy fractions (EQD2) in the overlapping volumes between initial and re-irradiated nasopharyngeal mucosal tissue can be effective in predicting the hazard of developing RINU in NPC patients undergoing radical re­irradiation with IMRT and we propose a EQD2_ [Formula: see text]D80 threshold of 137.035 Gy for the nasopharynx.

Prognostic value of circulating Epstein-Barr virus DNA level post-induction chemotherapy for patients with nasopharyngeal carcinoma: A recursive partitioning risk stratification analysis.

BACKGROUND: To evaluate the prognostic value of plasma Epstein-Barr virus (EBV) DNA level post-induction chemotherapy (IC) for patients with nasopharyngeal carcinoma (NPC). METHODS: A total of 893 newly diagnosed NPC patients treated with IC were retrospectively reviewed. The recursive partitioning analysis (RPA) was performed to construct a risk stratification model. The receiver operating characteristic (ROC) analysis was applied to determine the optimal cut-off value of post-IC EBV DNA. RESULTS: Post-IC EBV DNA levels and overall stage were independent predictors for distant metastasis-free survival (DMFS), overall survival (OS), and progression-free survival (PFS). The RPA model base on post-IC EBV DNA and overall stage categorized the patients into three distinct risk groups: RPA I (low-risk: stage II-III and post-IC EBV DNA < 200 copies/mL), RPA II (median-risk: stage II-III and post-IC EBV DNA ≥ 200 copies/mL, or stage IVA and post-IC EBV DNA < 200 copies/mL), and RPA III (high-risk: stage IVA and post-IC EBV DNA ≥ 200 copies/mL), with 3-year PFS of 91.1%, 82.6%, and 60.2%, respectively (p < 0.001). The DMFS and OS rates in different RPA groups were also distinct. The RPA model showed better risk discrimination than either the overall stage or post-RT EBV DNA alone. CONCLUSIONS: Plasma EBV DNA level post-IC was a robust prognostic biomarker for NPC. We developed an RPA model that provides improved risk discrimination over the 8th edition of the TNM staging system by integrating the post-IC EBV DNA level and the overall stage.

Failure pattern and suggestions for target volume delineation of carcinoma showing thymus-like differentiation treated with intensity-modulated radiotherapy.

BACKGROUND: To review our long-term clinical experience, analyze the failure patterns, and give suggestions for target volume delineation of carcinoma showing thymus-like differentiation (CASTLE) treated with intensity-modulated radiotherapy (IMRT). METHODS: From April 2008 to May 2019, 30 patients with CASTLE treated by postoperative or radical IMRT in our center were retrospectively reviewed. A total dose of 56-60 Gy in 28-30 fractions was prescribed to patients without residual disease and 66 Gy in 33 fractions for patients with residual or unresectable disease. Survival rates were calculated using the Kaplan-Meier method. Treatment-related toxicities were graded by National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 4.0. RESULTS: Among the 30 patients, 12 (40%) received partial resection or biopsy. Lateral lymph node metastasis was observed in 7 (23.3%) patients. During follow-up, regional lymph node recurrence occurred in 2 patients and distant metastasis in 5 patients. With a median follow-up time of 63.5 months, the 5-year local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS), overall survival (OS) and progression-free survival (PFS) rates were 100, 88.9, 78.9, 93.1 and 78.9%, respectively. For patients with no lateral neck node metastasis, prophylactic radiotherapy for lateral neck nodal regions failed to improve RRFS (p = 0.381) and OS (p = 0.153). CONCLUSION: Distant metastasis was the major failure pattern for CASTLE after surgery and IMRT. For patients with no lateral neck node metastasis, the omission of irradiation for lateral neck nodal regions seems to be safe and feasible.

Dissecting the heterogeneity of the microenvironment in primary and recurrent nasopharyngeal carcinomas using single-cell RNA sequencing.

Nasopharyngeal carcinoma (NPC) has a 10-15% recurrence rate, while no long term or durable treatment options are currently available. Single-cell profiling in recurrent NPC (rNPC) may aid in designing effective anticancer therapies, including immunotherapies. For the first time, we profiled the transcriptomes of ∼60,000 cells from four primary NPC and two rNPC cases to provide deeper insights into the dynamic changes in rNPC within radiation fields. Heterogeneity of both immune cells (T, natural killer, B, and myeloid cells) and tumor cells was characterized. Recurrent samples showed increased infiltration of regulatory T cells in a highly immunosuppressive state and CD8+ T cells in a highly cytotoxic and dysfunctional state. Enrichment of M2-polarized macrophages and LAMP3+ dendritic cells conferred enhanced immune suppression to rNPC. Furthermore, malignant cells showed enhanced immune-related features, such as antigen presentation. Elevated regulatory T cell levels were associated with a worse prognosis, with certain receptor-ligand communication pairs identified in rNPC. Even with relatively limited samples, our study provides important clues to complement the exploitation of rNPC immune environment and will help advance targeted immunotherapy of rNPC.

Local control and failure patterns after intensity modulated radiotherapy with reduced target volume delineation after induction chemotherapy for patients with T4 nasopharyngeal carcinoma.

BACKGROUND: The delineation of target volume after induction chemotherapy(IC) for nasopharyngeal carcinoma(NPC) is currently controversial. In this study, we aimed to analyze the long-term local control(LC) and failure patterns of T4 NPC treated with reduced target volume radiotherapy after IC. METHODS: From September 2007 to January 2013, 145 patients with T4 NPC were retrospectively reviewed. All patients received at least 1 cycle of IC followed by intensity modulated radiotherapy(IMRT). The gross tumor volume(GTV) was delineated according to the post-IC images for intracavity tumors and lymph nodes. The LC and overall survival (OS) rates were calculated using the Kaplan-Meier method. The location and extent of local failures were transferred to the pretreatment planning computed tomography (CT) for dosimetric analysis. RESULTS: With a median follow-up time of 95 months (range, 16-142 months), 23 local failures were found. The estimated 10-year LC and OS rates were 81.1%and 54.8% respectively. Among the 20 local failures with available diagnostic images, 18(90%) occurred within the 95% isodose lines and were considered in-field failures and 2(10%) were marginal. There was no outside-field failure. CONCLUSIONS: In-field failure was the major pattern of local failure for T4 NPC. IMRT with reduced target volume after IC seems to be feasible. Further researches exploring optimal volume and radiation dose for local advanced NPC in the era of IC are warranted.

Dosimetry of the brain and hypothalamus predicting acute lymphopenia and the survival of glioma patients with postoperative radiotherapy.

BACKGROUND: The aim of this study was to investigate dosimetric factors for predicting acute lymphopenia and the survival of glioma patients with postoperative intensity-modulated radiotherapy (IMRT). METHODS: A total of 148 glioma patients were reviewed. Acute lymphopenia was defined as a peripheral lymphocyte count (PLC) lower than 1.0 × 109 /L during radiotherapy with a normal level at pretreatment. PLCs with the corresponding dates and dose volume histogram parameters were collected. Univariate and multivariate Cox regression analyses were constructed to assess the significance of risk factors associated with lymphopenia and overall survival (OS). RESULTS: Sixty-nine (46.6%) patients developed lymphopenia during radiotherapy. Multivariate analyses revealed that the risk increased with the maximal dose of the hypothalamus (HT Dmax) ≥56 Gy (58.9% vs 28.5%, P = 0.002), minimal dose of the whole brain (WB Dmin) ≥2 Gy (54.3% vs 33.9%, P = 0.006), or mean dose of the WB (WB Dmean) ≥34 Gy (56.0% vs 37.0%, P = 0.022). Patients with older age, high-grade glioma, development of lymphopenia, high HT Dmax, WB Dmin, and WB Dmean had significantly inferior OS in the multivariate analyses. CONCLUSIONS: HT Dmax, WB Dmin, and WB Dmean are promising indicators of lymphopenia and the survival of glioma patients undergoing postoperative IMRT. The necessity and feasibility of dosimetric constraints for HT and WB is warranted with further investigation.

Dosimetric predictors of temporal lobe injury after intensity-modulated radiotherapy for T4 nasopharyngeal carcinoma: a competing risk study.

BACKGROUND: In patients with T4 nasopharyngeal carcinoma (NPC), death may occur prior to the occurrence of temporal lobe injury (TLI). Because such competing risk death precludes the occurrence of TLI and thus the competing risk analysis should be applied to TLI research. The aim was to investigate the incidence and predictive factors of TLI after intensity-modulated radiotherapy (IMRT) among T4 NPC patients. METHODS: From March 2008 to December 2014, T4 NPC patients treated with full-course radical IMRT at our center were reviewed retrospectively. A nested case-control study was designed for this cohort of patients. The cases were patients with TLI diagnosed by MRI during the follow-up period, and the controls were patients without TLI after IMRT matched 1:1 to each case by gender, age at diagnosis, intercranial involvement, and follow-up time. The end point was time to TLI or death without prior TLI. We analyzed the cumulative incidence function (CIF) and performed a competing risk regression model to identify the predictors of TLI. RESULTS: With a median follow-up of 40.1 months, 63 patients (63/506, 12.5%) developed TLI as diagnosed by MRI, and 136 deaths occurred during the period. The cumulative incidence of TLI at 5 years was 13.2%, while 26.7% died without prior TLI. The univariate analysis showed that all selected dosimetric parameters were associated with the occurrence of TLI. On multivariate analysis, D1cc and V20 remained statistically significant. Based on the area-under-the-curve (AUC) values, D1cc was considered the most predictive. The patients with D1cc > 71.14 Gy had a 7.920-fold increased risk of TLI compared with those with D1cc ≤71.14 Gy (P < 0.05). Similarly, V20 > 42.22 cc was found to result in a statistically significant higher risk of TLI (subdistribution hazard ratio [sHR] =3.123, P < 0.05). CONCLUSIONS: TL D1cc and V20 were predictive of TLI after IMRT for T4 NPC. They should be considered as first and second priorities of dose constraints of the TL. D1cc ≤71.14 Gy and V20 ≤ 42.22 cc could be useful dose-volume constraints for reducing the occurrence of TLI during IMRT treatment planning without obviously compromising the tumor coverage.

The prognostic value of tumor depth for cervical lymph node metastasis in hypopharyngeal and supraglottic carcinomas.

BACKGROUND: To analyze the prognostic value of the clinicopathological parameters of primary lesions for predicting cervical lymph node metastasis in patients with hypopharyngeal and/or supraglottic carcinoma. METHODS: We enrolled 127 patients with squamous cell carcinomas originating in the hypopharyngeal and/or supraglottic regions. RESULTS: Multivariate analysis identified the tumor depth as an independent predictive factor for lymph node metastasis (odds ratio, 4.959; 95% confidence interval, 2.290-10.739; P < 0.0001) with a predictive value of 0.966. A cutoff value of 4.5 mm was determined. CONCLUSION: The tumor depth of the primary lesion is a potent predictor of cervical lymph node metastasis in hypopharyngeal and supraglottic carcinomas. In cases with clinically negative nodal status, elective neck dissection should be adopted for patients with a tumor depth reaching 4.5 mm. Regular outpatient follow-up is recommended for patients with a tumor depth less than 1.0 mm. Close follow-up or preventative therapy should be considered between 1.0 and 4.5 mm.

Impact of tumor dimensions and lymph node density on the survival of patients with hypopharyngeal squamous cell carcinoma.

PURPOSE: To analyze the potential variables affecting the survival of patients undergoing primary surgery for hypopharyngeal squamous cell carcinoma. PATIENTS AND METHODS: Between August 2007 and December 2016, 93 patients with primary hypopharyngeal squamous cell carcinomas undergoing radical surgery at Fudan University Shanghai Cancer Center were reviewed. The clinicopathological features were analyzed retrospectively. The optimal cutoff values were determined based on the receiver operating characteristic curve analysis. Pearson correlation coefficients were used to assess the correlations between variables. The Kaplan-Meier and Cox proportional hazard methods were used to evaluate the impact of variables on overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS). RESULTS: Cox multivariate analysis revealed that a depth of invasion (DOI) ≥ 4.3 mm was correlated with inferior OS (P=0.045), DSS (P=0.046), and DFS (P=0.046). A primary tumor volume (PTV) ≥0.36 mL was related to poor OS (P=0.018), DSS (P=0.026), and DFS (P=0.036). A lymph node density (LND) ≥0.07 was also associated with worse OS (P=0.014) and DSS (P=0.045). Moreover, additional prognostic value was observed in the combined use of PTV and LND. CONCLUSION: The DOI, PTV, and LND obtained from the surgical specimens could provide additional valuable information for prognostic stratification and allowed the more appropriate selection of suitable candidates for more aggressive adjuvant therapy.

The prognostic value of preoperative prognostic nutritional index in patients with hypopharyngeal squamous cell carcinoma: a retrospective study.

BACKGROUND: To analyze the prognostic value of preoperative prognostic nutritional index (PNI) in predicting the survival outcome of hypopharyngeal squamous cell carcinoma (HPSCC) patients receiving radical surgery. METHODS: From March 2006 to August 2016, 123 eligible HPSCC patients were reviewed. The preoperative PNI was calculated as serum albumin (g/dL) × 10 + total lymphocyte count (mm-3) × 0.005. These biomarkers were measured within 2 weeks prior to surgery. The impact of preoperative PNI on overall survival (OS), progression-free survival (PFS), locoregional recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) were analyzed using Kaplan-Meier method and Cox proportional hazards model. RESULTS: Median value of 52.0 for the PNI was selected as the cutoff point. PNI value was then classified into two groups: high PNI (> 52.0) versus low PNI (≤ 52.0). Multivariate analysis showed that high preoperative PNI was an independent prognostic factor for better OS (P = 0.000), PFS (P = 0.001), LRFS (P = 0.005) and DMFS (P = 0.016). CONCLUSIONS: High PNI predicts superior survival in HPSCC patients treated with radical surgery. As easily accessible biomarkers, preoperative PNI together with the conventional TNM staging system can be utilized to enhance the accuracy in predicting survival and determining therapy strategies in these patients.

Radiation-induced hypothyroidism after IMRT for nasopharyngeal carcinoma: Clinical and dosimetric predictors in a prospective cohort study.

OBJECTIVES: To investigate the rate and risk factors for developing hypothyroidism (HT) in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: A total of 135 consecutive patients treated with IMRT for NPC were prospectively evaluated during a median follow up of 34.1months. Serum thyroid function assessments before and after IMRT were periodically monitored. To identify risk factors for HT occurrence, univariate and multivariate Cox regression analyses were performed. RESULTS: Thirty-nine patients (28.9%) developed primary HT. The 2- and 3-year incidences of primary HT were 29.6% and 43.9%, respectively. The median clinical latency for primary HT was 15.1months (3.2-33.8months). No cases of central HT were observed. Univariate and multivariate analyses revealed that the risk increased with younger age and decreased with higher pretreatment thyroid volume. Patients with thyroid mean dose ≥45Gy had a 4.9 times increased risk of HT than those receiving lower mean dose. Alternatively, the thyroid V45 below 0.5 and V50 below 0.35 were found to significantly lower the incidence rate of HT. CONCLUSION: The incidence of primary HT after IMRT for NPC continued to increase with time. The thyroid mean dose constraint was approximately 45Gy. We recommended plan optimization objectives to reduce thyroid V45 to 0.5 and V50 to 0.35.

Treatment of cerebral radiation necrosis with nerve growth factor: A prospective, randomized, controlled phase II study.

PURPOSE: A prospective, placebo controlled phase II trial was conducted to test the efficacy of Nerve Growth Factor (NGF) for the treatment of symptomatic temporal lobe necrosis (TLN). MATERIALS AND METHODS: Patients with progressive TLN were randomly assigned to either the control or the study group in a 1:1 ratio. The control group received corticosteroids with gradually reduced dosage. The study group received NGF with corticosteroids. NGF was dissolved in 2mL normal saline and injected intramuscularly at 18µg/time, once a day for 2months. The efficacy was evaluated by both the objective and subjective methods every 3-4months after treatment. The objective method compared volumes of the necrotic masses on MRI before and after treatment. The subjective method compared the neurocognitive score as evaluated by the mini-mental status examination (MMSE). RESULTS: Twenty-eight cases were enrolled into this study. The objective evaluation showed that the response rate (RR) in the study group was higher than the control group. The ratio was 10 versus 2 (p=0.006), and 12 versus 3 (p=0.002) at 3-4months and 6-8months after intervention, respectively. The subjective evaluation demonstrated both groups were effective in controlling the necrosis related symptoms in the first 6months after treatment. But NGF was more effective than corticosteroids at 9months (13 versus 4, p=0.001). The only observed side effect was mild pain at the injection site in 3 patients in the study group. CONCLUSIONS: Our results demonstrated that the process of TLN is not irreversible. NGF is more effective in recovering TLN than corticosteroids with little side effect. NGF has a longer duration in controlling the necrosis related symptoms than corticosteroids.

Experience with combination of nimotuzumab and intensity-modulated radiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma.

AIM: To evaluate the efficacy and safety of using nimotuzumab in combination with intensity-modulated radiotherapy (IMRT) in the primary treatment of locoregionally advanced nasopharyngeal carcinoma. METHODS: Between December 2009 and December 2013, 38 newly diagnosed patients with stage III-IV nasopharyngeal carcinoma were treated with IMRT and nimotuzumab concomitantly. The distribution of disease was stage III in 20 (52.6%), stage IV A in 9 (23.7%), and stage IV B in 9 (23.7%). All the patients received at least two cycles of cisplatin-based neoadjuvant chemotherapy followed by nimotuzumab 200 mg/week concurrently with IMRT. Acute and late radiation-related toxicities were graded according to the Acute and Late Radiation Morbidity Scoring Criteria of Radiation Therapy Oncology Group. RESULTS: With a median follow-up of 39.7 months (range, 13.3-66.5 months), the estimated 3-year local recurrence-free survival, regional recurrence-free survival, distant metastasis-free survival, progression failure-free survival, and overall survival rates were 92.8%, 92.9%, 89.5%, 78.7%, and 87.5%, respectively. The median cycle for nimotuzumab addition was 6 weeks. Grade 3 radiation-induced mucositis accounted for 36.8% of treated people. No skin rash and infusion reaction were observed, distinctly from what is reported in cetuximab-treated patients. CONCLUSION: Nimotuzumab plus IMRT showed promising outcomes in terms of locoregional control and survival, without increasing the incidence of radiation-related toxicities for patients.

Concurrent chemoradiotherapy was associated with a higher severe late toxicity rate in nasopharyngeal carcinoma patients compared with radiotherapy alone: a meta-analysis based on randomized controlled trials.

BACKGROUND: To investigate the incidence and risk of severe late toxicity with concurrent chemoradiotherapy (CCRT) in nasopharyngeal carcinoma patients. METHODS: Eligible studies included prospective randomized controlled trials (RCTs) evaluating CCRT versus radiotherapy alone in patients with nasopharyngeal carcinoma and in which data on severe late toxicities were available. Random effects or fixed effect models were applied to obtain the summary incidence, relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: Five RCTs with 1102 patients with NPC were included in this analysis. The summary incidence of overall severe late toxicities in patients receiving CCRT was 30.7% (95% CI, 18-47.2%) and the incidence of radiotherapy alone group was 21.7% (95% CI, 13.3-33.4%). The use of concurrent chemotherapy was associated with an increased risk of severe late toxicities, with a RR of 1.349 (95% CI, 1.108-1.643; P = 0.005). As for specific late toxicity, CCRT significantly increased the risk of ear deafness/otitis (RR = 1.567; 95% CI, 1.192-2.052), but other late toxicities were not significantly different. Patients receiving concurrent chemotherapy regimens with 3-week high-dose cisplatin (HC) have a higher risk of ear deafness/otitis (RR = 1.672; 95% CI, 1.174-2.382; P = 0.026). However, there was no significant increase in the RR of severe ear complication with the addition of non-3-week high-dose cisplatin (nonHC) regimens (RR = 1.433; 95% CI, 0.946-2.171; P = 0.095). CONCLUSION: With the present evidence, the addition of concurrent chemotherapy seems to increase the risk of severe late toxicities in patients with NPC, especially when using HC regimen for the occurrence of severe ototoxicity.

[Seasonal and Spatial Variations of Carbon Fractions in PM2.5 in Ningbo and the Estimation of Secondary Organic Carbon].

To investigate the seasonal and spatial variations of carbon fractions in PM2.5 in Ningbo, PM2.5 samples were collected at 5 sites in typical periods of 4 seasons from December 2012 to October 2013. The concentrations of organic carbon (OC) and elemental carbon (EC) were determined and the contribution of secondary organic carbon (SOC) was estimated. The result shows that: (1)the annual average of PM2.5 in Ningbo is 51. 6 µm.m-3. OC and EC account for 17% and 6% respectively. According to the result of the backward trajectory model, the concentrations of PM2.5 in winter and spring are higher mainly because of regional transport from inland China. (2) the OC/EC ratio and the correlation between OC and EC indicate that in summer a large sum of SOC is generated while in winter the influence of coal burning emission for heating in North China may be the main reason for high OC/EC ratio. (3) the contribution of SOC was estimated using an EC tracer method. The result shows that this method is not suitable for both winter and spring because of significant regional transport. The average concentrations of SOC in summer and autumn are 2. 5 µg.m-3 and 2. 3 µg.m-3, accounting for 42% and 28% of total OC respectively.

Study of the medial group retropharyngeal node metastasis from nasopharyngeal carcinoma based on 3100 newly diagnosed cases.

PURPOSE: Patterns of metastases to the medial retropharyngeal lymph nodes (RPLN) from nasopharyngeal carcinoma (NPC) have gain little attention. Since the incidence of dysphagia was closely related to whether the medial RPLN was irradiated, we carried out a prospective study to explore the patterns of the medial RPLN involvement. METHODS AND MATERIALS: Previously untreated NPC patients were required to receive MRI scan. MRI scanning sequences included pre-contrast T1WI, T2WI, and post-contrast T1WI with fat suppression. All images were evaluated by the multi-disciplinary treatment group of NPC. RESULTS: 3100 cases of NPC entered this study. 2679 (86.4%) cases had involved lymph nodes. The detailed distribution were: 2341 (87.4%) in level IIb, 1798 (67.1%) in level IIa, 1184 (44.2%) in level III, 350 (14.1%) in level IV, 995 (37.1%) in level V, 115(4.3%) in level Ib, 2012 (75.1%) in the retropharyngeal area. But only 6 (0.2%) were located at the medial group, accompanied with the lateral RPLN and other node metastasis. Only one medial RPLN can be identified in a patient, whereas the number of the lateral RPLNs per affected side varied between one and four. The average size of the medial and lateral RPLNs was 8±4 mm (range, 4-17 mm) and 16±9 mm (range, 5-53 mm), respectively. CONCLUSIONS: ① Involvement of the retropharyngeal nodes were mainly located at the lateral group, the medial RPLN was rarely seen. ② Metastasis to the medial RPLN was always accompanied with other node metastasis. ③ Only one medial RPLN can be identified in a patient, whereas the enlarged lateral RPLNs per affected side could be multiple. ④ The average size of the medial RPLN was smaller than the lateral RPLNs.

In vitro and in vivo studies on radiobiological effects of prolonged fraction delivery time in A549 cells.

Intensity-modulated radiation therapy, when used in the clinic, prolongs fraction delivery time. Here we investigated both the in vivoand in vitroradiobiological effects on the A549 cell line, including the effect of different delivery times with the same dose on A549 tumor growth in nude mice. The in vitroeffects were studied with clonogenic assays, using linear-quadratic and incomplete repair models to fit the dose-survival curves. Fractionated irradiation of different doses was given at one fraction per day, simulating a clinical dose-time-fractionation pattern. The longer the interval between the exposures, the more cells survived. To investigate the in vivoeffect, we used sixty-four nude mice implanted with A549 cells in the back legs, randomly assigned into eight groups. A 15 Gy radiation dose was divided into different subfractions. The maximum and minimum tumor diameters were recorded to determine tumor growth. Tumor growth was delayed for groups with prolonged delivery time (40 min) compared to the group receiving a single dose of 15 Gy (P< 0.05), and tumors with a 20 min delivery time had delayed growth compared to those with a 40 min delivery time [20' (7.5 Gy × 2 F) vs 40' (7.5 Gy × 2 F), P= 0.035; 20' (3 Gy × 5 F) vs 40' (3 Gy × 5 F); P= 0.054; 20' (1.67 Gy × 9 F) vs 40' (1.67 Gy × 9 F), P= 0.028]. A prolonged delivery time decreased the radiobiological effects, so we strongly recommend keeping the delivery time as short as possible.

The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer.

BACKGROUND: High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. METHODS: 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were randomized into 6 groups: the normal control group, the single fraction with 18 Gy group, the two subfractions with 30 min interval group, the seven subfractions with 5 min interval group, the two subfractions with 60 min interval group and the seven subfractions with 10 min interval group. The tumor growth tendency, the tumor growth delay and the mice survival time were analyzed. RESULTS: The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P < 0.05). The tumor grow delay of groups with prolonged delivery time 30 min was longer than that of groups with prolonged delivery time 60 min P < 0.05). There was no significant difference between groups with same delivery time (P > 0.05). Compared to the group with single fraction of 18 Gy, the groups with prolonged delivery time shorten the mice survival time while there was no significant difference between the groups with prolonged delivery time 30 min and the groups with prolonged delivery time 60 min. CONCLUSIONS: The prolonged delivery time with same radiation dose shorten the tumor growth delay and survival time in the mice implanted with Lewis lung cancer. The anti-tumor effect decreased with elongation of the total interfractional time.

Paclitaxel with cisplatin in concurrent chemoradiotherapy for locally advanced nasopharyngeal carcinoma.

The aim of this study was to evaluate the efficacy and the toxicity of paclitaxel and cisplatin in patients in concurrent radiotherapy for locally advanced nasopharyngeal carcinoma, and to see whether such a regime would be better tolerated than high dose cisplatin plus fluoracil in Chinese patients. Thirty-one patients with locally advanced nasopharyngeal carcinoma were enrolled. Patients were scheduled to receive two courses of concomitant chemotherapy, starting on day 1 and then day 28 during radiotherapy (70-76 Gy in 35-38 fractions in 7-7.5 weeks). Chemotherapy was given by intravenous infusion, paclitaxel 120 mg/m(2) in 3 h, cisplatin 75 mg/m(2) (25 mg/m(2) days 1-3). Adjuvant therapy was paclitaxel 135 mg/m(2) in 3 h, cisplatin 75 mg/m(2) (25 mg/m(2) days 1-3) on weeks 3, 6, 9 after radiotherapy. All patients completed radiotherapy, but for concomitant chemoradiotherapy, 20 of the 31 patients completed the 2 cycles of chemotherapy, while the other 11 could only receive 1 cycle due to various reasons. The median follow-up was 40 months, 2 patients developed locoregional recurrences, one of whom in the cervical lymph nodes, the other in the nasopharynx. The 3-year overall survival rate was 83.9% and the distant metastasis rate at 3 years was 13.6%. Grade 3-4 toxicities were neutropenia 12.9%, anaemia 6.45%, thrombocytopenia 3.22%, severe arrhythmia 3.2%, and hypersensitivity reaction 3.2%. In conclusion, paclitaxel with cisplatin as concurrent chemoradiotherapy for locoregionally advanced nasopharyngeal carcinoma is feasible, safe, and might improve regional control and survival rates in Chinese patients.