4DCT and CBCT based PTV margin in Stereotactic Body Radiotherapy(SBRT) of non-small cell lung tumor adhered to chest wall or diaphragm.

BACKGROUND: Large tumor motion often leads to larger treatment volumes, especially the lung tumor located in lower lobe and adhered to chest wall or diaphragm. The purpose of this work is to investigate the impacts of planning target volume (PTV) margin on Stereotactic Body Radiotherapy (SBRT) in non-small cell lung cancer (NSCLC). METHODS: Subjects include 20 patients with the lung tumor located in lower lobe and adhered to chest wall or diaphragm who underwent SBRT. Four-dimensional computed tomography (4DCT) were acquired at simulation to evaluate the tumor intra-fractional centroid and boundary changes, and Cone-beam Computer Tomography (CBCT) were acquired during each treatment to evaluate the tumor inter-fractional set-up displacement. The margin to compensate for tumor variations uncertainties was calculated with various margin calculated recipes published in the exiting literatures. RESULTS: The means (±standard deviation) of tumor centroid changes were 0.16 (±0.13) cm, 0.22 (±0.15) cm, and 1.37 (±0.81) cm in RL, AP, and SI directions, respectively. The means (±standard deviation) of tumor edge changes were 0.21 (±0.18) cm, 0.50 (±0.23) cm, and 0.19 (±0.44) cm in RL, AP, and SI directions, respectively. The means (±standard deviation) of tumor set-up displacement were 0.03 (±0.24) cm, 0.02 (±0.26) cm, and 0.02 (±0.43) cm in RL, AP, and SI directions, respectively. The PTV margin to compensate for lung cancer tumor variations uncertainties were 0.88, 0.98 and 2.68 cm in RL, AP and SI directions, which were maximal among all margin recipes. CONCLUSIONS: 4DCT and CBCT imaging are appropriate to account for the tumor intra-fractional centroid, boundary variations and inter-fractional set-up displacement. The PTV margin to compensate for lung cancer tumor variations uncertainties can be obtained. Our results show that a conventional 1.0 cm margin in the SI plane dose not suffice to compensate the geometrical variety of the tumor located in lower lobe and adhered to chest wall and diaphragm.

Analysis of the characteristics and prognosis of advanced non-small-cell lung cancer in older patients.

OBJECTIVE: Lung cancer is still the leading cause of cancer-related deaths worldwide. However, most elderly patients with advanced non-small-cell lung cancer (NSCLC) have been undertreated and the outcome related to age is controversial. A retrospective analysis was conducted for advanced NSCLC in order to investigate the characteristics and prognosis of older patients. METHODS: Medical records were collected from 165 patients with NSCLC (stages IIIA-IIIB) who had been treated with concurrent chemoradiotherapy (CRT) or radiotherapy from January 2009 to January 2011. The cases were divided into two age groups 1) patients ≥70 years old; 2) patients <70 years old. There were 73 patients in group I, 92 in group II. Patient characteristics, treatment toxicities, and prognosis were evaluated. RESULTS: Of the 165 patients analyzed, 34 patients (34/73) in group I received concurrent CRT while 47 (47/92) in group II completed that treatment. No significant difference was observed in the reason for patients who discontinued CRT in two groups (P>0.05). In the patients with adenocarcinoma, more cases were found in group II than that in group I; the more squamous cell carcinoma and the more smokers with squamous cell carcinoma were seen in older group (P<0.05). With a median follow-up of 20.5 months, the 1-year survival for group I and II were 49.3% and 40.2% respectively (P=0.243). Two-year survival for the two groups was 20.5% and 16.3% (P=0.483); 3-year survival was 9.6% and 9.8% (P=0.967). There was no significant difference between two groups statistically in survival by univariate analysis (P>0.05). The therapy-related toxicities in group I seem to be similar to the group II (P>0.05). CONCLUSION: More adenocarcinoma patients were found in youthful lung cancer and the more smokers with squamous cell carcinoma were seen in older group. Age is not the important factor for the selection and allocation of treatment in advanced NSCLC. The same prognosis and toxicities had been shown in older and young. Age may not be an independent increased risk of death in advanced NSCLC.

MiR-210 expression reverses radioresistance of stem-like cells of oesophageal squamous cell carcinoma.

AIM: To investigate the expression of miR-210 and the role it plays in the cell cycle to regulate radioresistance in oesophageal squamous cell carcinoma (ESCC). METHODS: MiR-210 expression was evaluated in 37 pairs of ESCC tissues and matched para-tumorous normal oesophageal tissues from surgical patients who had not received neoadjuvant therapy, and in the cells of two novel radioresistant cell lines, TE-1R and Eca-109R, using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The transient up-regulation of miR-210 expression in TE-1R and Eca-109R cells was studied using liposomes and was confirmed using qRT-PCR. The rate of cell survival after a series of radio-treatment doses was evaluated using the clone formation assay. Flow cytometry was used to detect the changes to the cell cycle patterns due to radiation treatment. RT-PCR and Western blot were used to detect the expression of ataxia telangiectasia mutated (ATM) and DNA dependent protein kinase (DNA-PKcs) after irradiation, and the cell sphere formation assay was used to evaluate the proliferative ability of the cancer stem-like cells. RESULTS: The level of miR-210 expression was significantly decreased, by 21.3% to 97.2%, with the average being 39.2% ± 16.1%, in the ESCC tissues of most patients (81.1%, 30 of 37 vs patients with high miR-210 expression, P < 0.05). A low level of expression of miR-210 was correlated with a poorly differentiated pathological type (P < 0.01) but was not correlated with the T-stage or lymph node infiltration (both P > 0.05). Early local recurrences (< 18 mo, n = 19) after radiotherapy were significantly related with low miR-210 expression (n = 13, P < 0.05). The level of miR-210 was decreased by approximately 73% (vs TE-1, 0.27 ± 0.10, P < 0.01) in the established radioresistant TE-IR cell line and by 52% (vs Eca-109, 0.48 ± 0.17, P < 0.05) in the corresponding Eca-109R line. Transient transfection with a miR-210 precursor increased the level of miR-210 expression, leading to a significant increase in cell survival after radiotherapy (P < 0.05). Twenty-four hours after radiation, the proportion of pmiR-210 cells in S phase was increased (vs control cells, 30.4% ± 0.4%, and vs untreated TE-1R cells, 23.3% ± 0.7%, P < 0.05 for both). The levels of DNA-PKcs (0.21 ± 0.07) and ATM (0.12 ± 0.03, P < 0.05) proteins were significantly lower in the PmiR-210 cells than in control cells, but no differences were found in the levels of the corresponding mRNAs in the two cell types (P > 0.05 for all). Exogenous miR-210 expression decreased the diameter of pmiR-210 cell spheres (vs control cells, 0.60 ± 0.14, P < 0.05). CONCLUSION: MiR-210 expression is negatively correlated with the pathological type and the local survival rate after radiotherapy, and high expression of miR-210 may reverse the radioresistance of ESCC stem-like cells.

Cyclooxygenase-2 inhibitor NS398 enhances radiosensitivity of radioresistant esophageal cancer cells by inhibiting AKT activation and inducing apoptosis.

This study aimed to evaluate the radiosensitizing effect of a COX-2 inhibitor, NS398, and its mechanism in radioresistant esophageal cancer Eca109R50Gy cells. NS398 enhanced radiosensitivity of Eca109R50Gy cells, characterized by redistribution of cell cycle, inhibition of DNA-dependent protein kinase catalytic subunit expression and induction of apoptosis. NS398 also reduced phospho-AKT level, upregulated expression of Bax and both procaspase-3 and active caspase-3, and downregulated Bcl-2 expression. Finally, NS398-induced radiosensitization was partly reversed by insulin-like growth factor-1, but not by prostaglandin E2. Our results suggest that NS398 may enhance radiosensitivity of Eca109R50Gy cells through blocking AKT activation and inducing apoptosis.

[Quality control of clinical-grade recombinant adenovirus used in gene therapy].

OBJECTIVE: To establish the quality control methods and reference standards for clinical-grade recombinant adenovirus products for human gene therapy. METHODS: The Infectivity of clinical grade recombinant adenoviral vectors is determined by a TCID(50) assay. The purity is determined by a high-performance liquid chromatography (HPLC) assay. A549 cells were used in replication competent adenovirus (RCA) assay of samples by observation of the cytopathic effect. Other quality control assays were performed in accordance with the SFDA Regulations for Biological Products. RESULTS: The recombinant adenovirus encoding human p53 gene produced at SiBiono (Lot 20010701) has the following quality attributes: viral particle concentration: 1.03 (10(12) VP/ml, infectivity titer: 5.01 (10(10) IU/ml, specific infectivity (IU/VP): 4.86%, higher than the 3.3% required by the Food and Drug Administration (FDA), USA; Purity by HPLC analysis: 98.62%, higher than the 95% purity specified by SFDA; and level of RCA: less than 1 RCA/3 (10(10) VP, meeting the standards established by SFDA. CONCLUSIONS: A whole set of quality standards of clinical-grade recombinant adenovirus vectors has been established so as to ensure the clinical safety and efficacy of recombinant adenoviral vectors for human gene therapy.