Integrative Single-Cell RNA-Seq and ATAC-Seq Analysis of Mouse Corneal Epithelial Cells.

Purpose: Corneal epithelial homeostasis is maintained by coordinated gene expression across distinct cell populations, but the gene regulatory programs underlying this cellular diversity remain to be characterized. Here we applied single-cell multi-omics analysis to delineate the gene regulatory profile of mouse corneal epithelial cells under normal homeostasis. Methods: Single cells isolated from the cornea epithelium (with marginal conjunctiva) of adult mice were subjected to scRNA-seq and scATAC-seq using the 10×Genomics platform. Cell types were clustered by the graph-based visualization method uniform manifold approximation and projection and unbiased computational informatics analysis. The scRNA-seq and scATAC-seq datasets were integrated following the integration pipeline described in ArchR and Seurat. Results: We characterized diverse corneal epithelial cell types based on gene expression signatures and chromatin accessibility. We found that cell type-specific accessibility regions were mainly located at distal regions, suggesting essential roles of distal regulatory elements in determining corneal epithelial cell diversity. Trajectory analyses revealed a continuum of cell state transition and higher coordination between transcription factor (TF) motif accessibility and gene expression during corneal epithelial cell differentiation. By integrating transcriptomic and chromatin accessibility analysis, we identified cell type-specific and shared gene regulation programs. We also uncovered critical TFs driving corneal epithelial cell differentiation, such as nuclear factor I (NFI) family members, Rarg, Elf3. We found that nuclear factor-κB (NF-κB) family members were positive TFs in limbal cells and some superficial cells, but they were involved in regulating distinct biological processes. Conclusions: Our study presents a comprehensive gene regulatory landscape of mouse cornea epithelial cells, and provides valuable foundations for future investigation of corneal epithelial homeostasis in the context of cornea pathologies and regenerative medicine.

Is pre-oxygenation with high-flow nasal oxygen safe? randomized control trial of 56 cases of elderly patients during induction of general anesthesia with endotracheal intubation / 南方医科大学学报

OBJECTIVE@#To evaluate the safety of preoxygenation with high-flow nasal oxygenation in elderly patients during induction of general anesthesia with endotracheal intubation.@*METHODS@#Fifty-six elderly patients without difficult airway were randomized equally into high-flow nasal oxygen group (HF group) and conventional mask oxygen group (M group). Preoxygenation was performed for 5 min before induction of general anesthesia and endotracheal intubation. Oxygenation was maintained during laryngoscopy in HF group, and ventilation lasted until laryngoscopy in M group. For all the patients, the general data, cross-sectional area (CSA) of the gastric antrum measured by ultrasonography, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2) and arterial oxygen saturation (cSO2) were recorded before preoxygenation (T1), at 5 min of preoxygenation (T2) and immediately after intubation (T3). The safety time of asphyxia, intubation time, times of mask ventilation and postoperative complications were compared between the two groups.@*RESULTS@#The general data were comparable between the two groups. After 5 min of preoxygenation, PaO2 and cSO2 were significantly increased in both groups, and PaO2 was significantly higher in HF group than in M group (F=118.108 vs 9.511, P < 0.05). Both PaO2 and cSO2 decreased after intubation, but PaO2 decreased more slowly in HF group and still remained higher than that at T1; cSO2 decreased significantly in M group to a lower level than that at T1. Compared with those in M group, the patients in HF group showed a significantly longer safety time of asphyxia (t=5.305, P < 0.05) with fewer times of mask ventilation (χ2= 6.720, P < 0.05). PaCO2 increased after intubation in both groups but was comparable between the two groups (F=3.138, P > 0.05).@*CONCLUSION@#High-flow nasal oxygen is safe, simple and effective for pre-oxygenation, which, as compared with the conventional oxygen mask, improves arterial oxygen partial pressure and prolongs the safety time of asphyxia to ensure the safety of airway management during induction of general anesthesia in elderly patients with endotracheal intubation.

A single-dose of stellate ganglion block for the prevention of postoperative dysrhythmias in patients undergoing thoracoscopic surgery for cancer: A randomised controlled double-blind trial.

BACKGROUND: New-onset arrhythmias and sleep disturbances are frequently observed during the postoperative period in patients undergoing thoracic surgery. OBJECTIVE: We evaluated the effectiveness of a single-dose stellate ganglion block (SGB) to prevent the occurrence of arrhythmias in patients undergoing thoracic surgery for cancer. DESIGN: Randomised controlled double-blind study. SETTING: Single university hospital. PATIENTS: Ninety patients with lung cancer or oesophagal cancer scheduled for elective video-assisted thoracoscopic surgery were randomly randomised into one of two equal groups (the SGB group and control group, n = 40 each). INTERVENTIONS: Patients received a single dose of 5 ml of 0.5% ropivacaine during ultrasound-guided SGB before induction of general anaesthesia in the SGB group. MAIN OUTCOME MEASURES: Holter ECG was continuously monitored during the first 48 postoperative hours, and sleep state was monitored during the first two postoperative nights. RESULTS: The incidences of postoperative supraventricular tachycardias were lower in the SGB group compared with the control group during the first 48 postoperative hours; 11.6 (5/43) vs. 31.8% (14/44), respectively, P = 0.023 (odds ratio 0.28, 95% confidence interval 0.09 to 0.87). The SGB also prolonged the total sleep time and increased the sleep efficiency during the first two postoperative nights. The duration of stage N2 sleep was longer in the SGB group compared with the control group [28 (interquartile range, 14 to 58) to 94 (interquartile range, 69 to 113) min, P = 0.016] on the first postoperative night. There were no differences in the duration of stage N1 and N3 sleep (P = 0.180, 0.086, respectively) on the first postoperative night, and the duration of stage N1, N2 and N3 sleep (P = 0.194, 0.057, 0.405, respectively) on the second postoperative night between the groups. CONCLUSION: A pre-operative SGB effectively prevented the occurrence of postoperative supraventricular tachycardias and improves the objective sleep quality in patients undergoing thoracic surgery for cancer. TRIAL REGISTRATION NUMBER: ChiCTR-1900023064.

Exploring the Molecular Mechanism underlying the Stable Purple-Red Leaf Phenotype in Lagerstroemia indica cv. Ebony Embers.

Lagerstroemia indica is an important ornamental tree worldwide. The development of cultivars with colorful leaves and increased ornamental value represents one of the current main research topics. We investigated the anthocyanin profiles in two contrasting cultivars for leaf color phenotypes and explored the underlying molecular basis. Both cultivars display purple-red young leaves (Stage 1), and when the leaves mature (Stage 2), they turn green in HD (Lagerstroemia Dynamite) but remain unchanged in ZD (Lagerstroemia Ebony Embers). Seven different anthocyanins were detected, and globally, the leaves of ZD contained higher levels of anthocyanins than those of HD at the two stages with the most pronounced difference observed at Stage 2. Transcriptome sequencing revealed that in contrast to HD, ZD tends to keep a higher activity level of key genes involved in the flavonoid-anthocyanin biosynthesis pathways throughout the leaf developmental stages in order to maintain the synthesis, accumulation, and modification of anthocyanins. By applying gene co-expression analysis, we detected 19 key MYB regulators were co-expressed with the flavonoid-anthocyanin biosynthetic genes and were found strongly down-regulated in HD. This study lays the foundation for the artificial manipulation of the anthocyanin biosynthesis in order to create new L. indica cultivars with colorful leaves and increased ornamental value.

Analysis of codon usage patterns in "Lonicerae Flos" (Lonicera macranthoides Hand. -Mazz.) based on transcriptome data.

Lonicera macranthoides Hand. -Mazz. is an important medicinal and economical plant in China, however, the codon usage bias (CUB) in L. macranthoides genes is still unknown. In this study, L. macranthoides transcriptome sequencing has been completed, and codon usage patterns in 36,090 reconstructed genes from the L. macranthoides transcriptome were examined. The mean GC content and GC3 value is 44.9% and 43.1%, respectively, which indicates that nucleotide contents of L. macranthoides genome is somewhat AT rich, and its codon bias pattern tends to use A/T-ending codons. According to neutrality plot, ENC plot, PR2-Bias plot and correspondence analysis, we know that both compositional constraint under selection and mutation could affect the CUB in L. macranthoides, and the mutation is the most determinant factor. Meanwhile, gene expression levels can influence its codon usage pattern. Furthermore, we identified 29 optimal codons and most of them ended with A/U. The study will lay a foundation for future research on gene prediction, genetic engineering and molecular evolution in L. macranthoides.

Neoadjuvant chemotherapy with different dose regimens of docetaxel, cisplatin and fluorouracil (TPF) for locoregionally advanced nasopharyngeal carcinoma: a retrospective study.

OBJECTIVE: Compare high- vs. low-dose TPF neoadjuvant chemotherapy with chemoradiotherapy in Chinese patients with locoregionally advanced nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Retrospective analysis of 210 stage III/IV NPC patients treated between April 1, 2012 and April 1, 2014; 138 received three cycles of high-dose TPF (H-TPF) every 3 weeks at Zhejiang Cancer Hospital and 72, three cycles of low-dose TPF (L-TPF) every 3 weeks at Sun Yat-Sen University Cancer Center. H-TPF was docetaxel (75 mg/m2; 1 h infusion), cisplatin (75 mg/m2; 0.5-3 h), then 5-fluorouracil (600 mg/m2/day; 4 days). L-TPF was docetaxel (60 mg/m2), cisplatin (65 mg/m2), then 5-fluorouracil (550 mg/m2/day; 5 days). All patients received chemoradiotherapy. RESULTS: During neoadjuvant chemotherapy, treatment delays were more frequent for H-TPF than L-TPF (33.3% vs. 19.4%; P = 0.034). During chemoradiotherapy, grade III-IV anemia, thrombocytopenia and neutropenia were more common for H-TPF than L-TPF (P < 0.001, P < 0.001, P = 0.048). Fewer patients in the H-TPF group finished two cycles of concurrent chemotherapy (81.2% vs. 100%, P < 0.001). Three-year PFS (84.5% vs. 80.6%, P = 0.484) and OS (91.1% vs. 93.5%, P = 0.542) were not significantly different between H-TPF and L-TPF. CONCLUSIONS: L-TPF neoadjuvant chemotherapy has substantially better tolerance and compliance rates and similar treatment efficacy to H-TPF neoadjuvant chemotherapy in locoregionally-advanced NPC.

[Research on Identification of Organic Gunshot Residue with Micro-Raman Spectroscopy].

A rapid approach for the nondestructive, accurate detection of organic gunshot residue was investigated. Raman microscopy was used to identify organic gunshot residue and the propellant in ammunition. The optimal excitation wavelength for the detection of organic particles using Raman spectroscopy was 473 nm. The Raman spectra of organic gunshot residue obtained using 473 nm laser excitation can effectively avoid the interference of fluorescence. The results demonstrated that the organic particles were mainly from the partially burned propellant particles. Meanwhile it was proved that the main component was basically consistent with the propellant except somehow damage in chemical structure or degree of crystallization with Raman spectra. The surface color of organic particles was mainly brassiness, dark gray. A lot of craters were distributed on the surface of organic particles. Spherical inorganic particles with metallic luster attached to the surface of organic particles can be regarded as the typical characteristics of gunshot residue.

Application of artificial intelligence in diagnosis of diabetes / 中国医学装备

To analyze the application and research direction of artificial intelligence in the diagnosis field of diabetes through summarized the methods and principle of artificial intelligence, artificial neural network, expert system and data mining. The diagnosis of diabetes need be supported by large medical resource. The artificial intelligence is applied in the diagnosis of diabetes not only can save medical resource but also can help patients with diabetes and high risk group of diabetes to grasp their state of illness in time, and reduce the sickening risk of diabetic complication.

High-risk factors of parotid lymph node metastasis in nasopharyngeal carcinoma: a case-control study.

BACKGROUND: Although parotid-sparing IMRT decreased the dose distribution of parotid, parotid region recurrence has been reported. Prophylactic irradiation in parotid area would be necessary in patients with high risk of parotid lymph node metastasis (PLNM). This study was to detect the high-risk factors of PLNM in nasopharyngeal carcinoma. METHODS: This was a 1:2 case-control study. All patients in this study were newly diagnosed NPC with N2-3 classification from January 2005 to December 2012. Cases were 22 sides with ipsilateral PLNM. Controls were 44 patients who were randomly selected from N2-3 disease in database. RESULTS: 20/1096 (1.82 %) NPC patients were found PLNM. Sum of the longest diameter for multiple lymph nodes (SLD) in level II was larger in case group than that in control group (6.0 cm vs. 3.6 cm, p = 0.003). Level II lymph node necrosis, level Va/b involvement, and rare neck areas involvement were more common in case group (p = 0.016, p = 0.034, and p < 0.001, respectively). RPN, level III, and level IV metastases showed no significant difference between the two groups. Multivariate analysis in logistic regression showed that only SLD ≥5 cm in II area (OR = 4.11, p = 0.030) and rare neck areas involvement (OR = 3.95, p = 0.045) were associated with PLNM in NPC patients. CONCLUSIONS: PLNM was an uncommon event in NPC patients. SLD ≥5 cm in level II and involvement in rare-neck areas may be potentially high-risk factors for PLNM. Sparing parotid in IMRT was not recommended for NPC patients with high risks of PLNM.

miR-625 suppresses cell proliferation and migration by targeting HMGA1 in breast cancer.

Dysregulation of microRNA contributes to the high incidence and mortality of breast cancer. Here, we show that miR-625 was frequently down-regulated in breast cancer. Decrease of miR-625 was closely associated with estrogen receptor (P = 0.004), human epidermal growth factor receptor 2 (P = 0.003) and clinical stage (P = 0.001). Kaplan-Meier and multivariate analyses indicated miR-625 as an independent factor for unfavorable prognosis (hazard ratio = 2.654, 95% confident interval: 1.300-5.382, P = 0.007). Re-expression of miR-625 impeded, whereas knockdown of miR-625 enhanced cell viabilities and migration abilities in breast cancer cells. HMGA1 was confirmed as a direct target of miR-625. The expressions of HMGA1 mRNA and protein were induced by miR-625 mimics, but reduced by miR-625 inhibitor. Re-introduction of HMGA1 in cells expressing miR-625 distinctly abrogated miR-625-mediated inhibition of cell growth. Taken together, our data demonstrate that miR-625 suppresses cell proliferation and migration by targeting HMGA1 and suggest miR-625 as a promising prognostic biomarker and a potential therapeutic target for breast cancer.

Nasopharyngeal carcinoma with intracranial extension in the era of intensity-modulated radiotherapy: case-control study using propensity score matching method.

The objective of the study was to evaluate long-term survival outcomes and toxicity of T4 classification nasopharyngeal carcinoma (NPC) with intracranial extension (IE group) or without intracranial extension (non-IE group) after intensity-modulated radiotherapy (IMRT) using the propensity score matching method. After generating propensity scores given the covariates of age, sex, N classification, and concurrent chemotherapy, 132 patients in each group were matched. The 5-year local failure-free survival rate and the 5-year overall survival rate in the IE group were lower than the patients in the non-IE group (74.6 vs. 88.9 %, p = .008; 51.1 vs. 71.9 %, p = .005). Grade 2 hypothyroidism was more common in the IE group (13.2 vs. 3.4 %, p = .029). For patients with T4 classification NPC after IMRT, patients with intracranial extension need more attention to the thyroid gland function and are more likely to experience local failure and death than patients without intracranial extension.

Intensity-modulated radiotherapy for cervical esophageal squamous cell carcinoma: clinical outcomes and patterns of failure.

The objective of the study was to report clinical outcomes and patterns of failure for these patients with cervical esophageal squamous cell carcinoma (CESCC) treated with intensity-modulated radiotherapy (IMRT). A total of 64 patients with CESCC treated with definitive IMRT from May 2005 to March 2012 in our center were analyzed. Forty-two patients received radiotherapy alone and 22 patients received concurrent chemoradiotherapy. The location and extent of locoregional failures were transferred to the pretreatment planning computed tomography for dosimetry analysis. For all patients, the overall 2-year local failure-free survival, regional failure-free survival, distant failure-free survival, and overall survival rate was 74.5, 88.0, 66.6 and 42.5 %, respectively. Twenty-eight patients had developed treatment failure. Of the 28 patients, 14, 5, and 18 had developed local failure, regional failure, and distant metastasis, respectively. All of the 14 local failures were considered in-field failures. Of the five regional failures, three were considered in-field failures and two were marginal failures. The most frequently observed acute toxicity was mainly Grade 1 or 2. The incidence of acute Grade 3 mucositis (including pharyngitis), skin reaction, and leukopenia was 4.7, 12.5 and 10.9 %, respectively. IMRT provides satisfactory locoregional control for CESCC. Distant metastasis remains the predominate pattern of failure and the predominate pattern of locoregional failures is in-field failure.

Laryngoscope and a new tracheal tube assist lightwand intubation in difficult airways due to unstable cervical spine.

PURPOSE: The WEI Jet Endotracheal Tube (WEI JET) is a new tracheal tube that facilitates both oxygenation and ventilation during the process of intubation and assists tracheal intubation in patients with difficult airway. We evaluated the effectiveness and usefulness of the WEI JET in combination with lightwand under direct laryngoscopy in difficult tracheal intubation due to unstable cervical spine. METHODS: Ninety patients with unstable cervical spine disorders (ASA I-III) with general anaesthesia were included and randomly assigned to three groups, based on the device used for intubation: lightwand only, lightwand under direct laryngoscopy, lightwand with WEI JET under direct laryngoscopy. RESULTS: No statistically significant differences were detected among three groups with respect to demographic characteristics and C/L grade. There were statistically significant differences between three groups for overall intubation success rate (p = 0.015) and first attempt success rate (p = 0.000). The intubation time was significantly longer in the WEI group (110.8±18.3 s) than in the LW group (63.3±27.5 s, p = 0.000) and DL group (66.7±29.4 s, p = 0.000), but the lowest SpO2 in WEI group was significantly higher than other two groups (p<0.01). The WEI JET significantly reduced successful tracheal intubation attempts compared to the LW group (p = 0.043). The severity of sore throat was similar in three groups (p = 0.185). CONCLUSIONS: The combined use of WEI JET under direct laryngoscopy helps to assist tracheal intubation and improves oxygenation during intubation in patients with difficult airway secondary to unstable spine disorders. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-TRC-14005141.

Concurrent chemotherapy for T4 classification nasopharyngeal carcinoma in the era of intensity-modulated radiotherapy.

OBJECTIVE: To evaluate concurrent chemotherapy for T4 classification nasopharyngeal carcinoma (NPC) treated by intensity-modulated radiotherapy (IMRT). METHODS: From July 2004 to June 2011, 180 non-metastatic T4 classification NPC patients were retrospectively analyzed. Of these patients, 117 patients were treated by concurrent chemoradiotherapy (CCRT) using IMRT and 63 cases were treated by IMRT alone. RESULTS: The median follow-up time was 58.97 months (range, 2.79-114.92) months. For all the patients, the 1, 3 and 5-year local failure-free survival (LFFS) rates were 97.7%, 89.2% and 85.9%, regional failure free survival (RFFS) rates were 98.9%, 94.4% and 94.4%, distant failure-free survival (DFFS) rates were 89.7%, 79.9% and 76.2%, and overall survival (OS) rates were 92.7%, 78.9% and 65.3%, respectively. No statistically significant difference was observed in LFFS, RFFS, DFFS and OS between the CCRT group and the IMRT alone group. No statistically significant difference was observed in acute toxicity except leukopenia (p = 0.000) during IMRT between the CCRT group and the IMRT alone group. CONCLUSION: IMRT alone for T4 classification NPC achieved similar treatment outcomes in terms of disease local control and overall survival as compared to concurrent chemotherapy plus IMRT. However, this is a retrospective study with a limited number of patients, such results need further investigation in a prospective randomized clinical trial.

Update report of T4 classification nasopharyngeal carcinoma after intensity-modulated radiotherapy: an analysis of survival and treatment toxicities.

OBJECTIVE: To evaluate the long-term survival outcomes and toxicity of a larger series of patients with non-metastatic T4 classification nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT). MATERIALS AND METHODS: From March 2004 to June 2011, 335 non-metastatic T4 classification NPC patients treated by IMRT were analyzed retrospectively. Treatment induced toxicities were scored according to the Common Terminology Criteria for Adverse Events version 3.0. RESULTS: With a median follow-up time of 53.6 months (range, 2.8-114.9 months), the 5-year local failure-free survival (LFFS), regional failure free survival (RFFS), distant failure-free survival (DFFS), and overall survival (OS) were 84.1%, 92.2%, 74.1%, and 63.0%, respectively. At their last follow-up visit, 118 patients (35.2%) had developed treatment failure. Distant metastasis was the major failure pattern after treatment. The most common toxicities were mainly in grade 1 or 2. Concurrent chemotherapy failed to improve survival rates for patients with T4 classification NPC. CONCLUSION: The results of T4 classification NPC treated by IMRT were excellent, and distant metastasis was the most commonly failure pattern. Treatment-related toxicities were well tolerable. The role of concurrent chemotherapy for T4 classification NPC needs to be further investigated in the era of IMRT.

Primary radiotherapy compared with primary surgery in cervical esophageal cancer.

IMPORTANCE: The management of cervical esophageal cancer (CEC) is controversial. The advantages of radiotherapy (RT) for CEC are lower rates of acute morbidity and mortality compared with surgery and potential for larynx preservation. The advantage of surgery is that the transposed stomach may function better over the long term than an irradiated esophagus, which tends to become stenotic over time. Which one is the primary treatment of CEC? OBJECTIVE: To evaluate treatment outcomes of primary RT and primary surgery in patients with CEC. DESIGN, SETTING, AND PARTICIPANTS: This retrospective study conducted in a university hospital included 224 patients treated for CEC between 2001 and 2012. INTERVENTIONS: One hundred and sixty-one patients who received primary RT with or without subsequent surgery were assigned to the RT group, including 133 patients who received RT alone or RT with concurrent chemotherapy and 28 patients who received preoperative RT plus surgery. Sixty-three patients who received primary surgery with or without subsequent RT were assigned to the primary surgery group, including 27 patients who received surgery alone and 36 patients who received surgery plus postoperative RT. MAIN OUTCOMES AND MEASURES: The rates of overall 2-year local failure-free survival (FFS), regional FFS, distant FFS, and overall survival for patients undergoing primary RT and primary surgery were compared. A separate analysis using matched cases between the primary RT group and primary surgery group was conducted. RESULTS: The median follow-up time was 15.1 months. The rates of overall 2-year local FFS, regional FFS, distant FFS, and overall survival for patients undergoing primary RT and primary surgery were 69.9% and 68.6%, 79.5% and 69.8%, 74.3% and 62.5%, 49.3% and 50.7%, respectively (P > .05 for all). Matched-case analyses did not show any significant differences in measured survival rates between the treatment groups. CONCLUSIONS AND RELEVANCE: Given the similarities in rates of local FFS, regional FFS, distant FFS, and overall survival between the primary RT and primary surgery CEC treatment groups, we recommend primary RT for larynx preservation, with surgery offered subsequently for patients who do not respond to RT.

Pattern of Failure in Surgically Treated Patients with Cervical Esophageal Squamous Cell Carcinoma.

OBJECTIVE: The aim of this study was to analyze the pattern of failure in patients who have undergone surgical resection for cervical esophageal squamous cell carcinoma. STUDY DESIGN: Case series with chart review. SETTING: University hospital. SUBJECTS AND METHODS: Sixty-two patients who had undergone surgical resection of cervical esophageal squamous cell carcinoma from January 2001 through April 2012. Sites of failure were documented. RESULTS: Twenty-nine patients had developed treatment failure. Of the 29 patients, 14, 13, and 14 had developed local failure, regional failure, and distant metastasis, respectively. Of the 13 regional failures, the images of 2 patients were lost. The other 11 regional failures included left lateral nodal disease at level II (n = 2), level III (n = 4), and level IV (n = 7); right lateral nodal disease at level II (n = 2), level III (n = 3), and level IV (n = 3); and level VI (n = 4). The overall 2-year local failure-free survival rate and regional failure-free survival rates were 79.6% and 58.6% (P = .04) for patients with stage II disease and 79.6% and 59.6% (P = .054) for patients with stage III disease, respectively. CONCLUSIONS: The pattern of failure of cervical esophageal squamous cell carcinoma is characterized by early locoregional failure, especially in patients with stage III disease.

Recurrence of nasopharyngeal carcinoma in the parotid region after definitive intensity-modulated radiotherapy.

PURPOSE: To discuss the clinical characteristics and management of periparotid recurrence of nasopharyngeal carcinoma after definitive intensity-modulated radiotherapy. PATIENTS AND METHODS: The authors retrospectively reviewed the charts of 716 patients with nasopharyngeal carcinoma who underwent intensity-modulated radiotherapy at their center from January 2005 through December 2010. Disease recurred in a spared parotid gland in 10 patients (1.4%). After periparotid recurrence, 4 patients received surgery alone, 1 patient received radiotherapy alone, 2 patients received chemotherapy alone, 2 patients received surgery plus chemotherapy, and 1 patient received surgery plus radiotherapy. RESULTS: After a median follow-up of 42.6 months (19.8 to 86.0 months), 4 patients died of tumor progression. The median survival time after periparotid recurrence was 25.1 months (5.0 to 74.5 months). CONCLUSIONS: Periparotid recurrence is an uncommon pattern of failure after definitive intensity-modulated radiotherapy for nasopharyngeal carcinoma, and there were some long-term survivors in this patient population after salvage treatment.

Clinical characteristics and patterns of failure in the parotid region after intensity-modulated radiotherapy for nasopharyngeal carcinoma.

OBJECTIVE: To discuss the clinical characteristics and patterns of failure in the parotid region after intensity-modulated radiotherapy for nasopharygeal carcinoma. MATERIALS AND METHODS: We retrospectively reviewed the charts of 716 patients with nasopharygeal carcinoma who underwent intensity-modulated radiotherapy in our centre from January 2005 to December 2010. Disease recurred in a spared parotid gland in 10 patients (1.4%). There were 2 females and 8 males with a median age of 38.5 (34-53) years. The most common presenting symptom was a swelling in pre-auricular region (7/10). Parotid glands were spared bilaterally in these patients. None of these patients had undergone previous radiotherapy or surgical treatment of the head and neck. The location of periparotid failures were transferred to the pretreatment planning computed tomography for dosimetry analysis. RESULTS: The median time from day 1 of radiotherapy to periparoid recurrence was 17.4 (4.4-40.5) months. The median survivial after periparoid recurrence was 25.1 (5.0-74.5) months. There were 9 (90%) patients with lateral retropharyngeal lymphadenopathy. Seven of the periparotid failures were marginal. Of the 7 marginal failures, 6 occurred at the ipslateral parotid of the primary tumor centre. The average mean dose of the ipslateral parotid was 38.1 (32.3-44.1) Gy. CONCLUSION: Periparotid recurrence is an uncommon pattern of failure after definitive intensity-modulated radiotherapy for nasopharygeal carcinoma. To reduce the risk of periparotid recurrence,one possible strategy is to lessen the dose constraint criteria to ipslateral parotid of the primary tumor centre especially for nasopharygeal carcinoma with lateral retropharyngeal lymphadenopathy.