Effect of dwell time deviation constraint on the three-dimensional brachytherapy plans for cervical cancer / 中华放射肿瘤学杂志

Objective:To investigate the effect of dwell time deviation constraint of inverse optimization on the quality and position error robustness of three-dimensional (3D) brachytherapy plans for cervical cancer.Methods:A total of 20 patients with cervical cancer receiving 3D brachytherapy treatment in Xiangya Hospital Central South University from August 2020 to August 2021 were retrospectively selected. All plans were designed using the Eclipse treatment planning system, and the dwell time deviation constraint parameter smooth value in the system were set to 0.00, 0.25, 0.50, 0.75, and 1.00, respectively. An inverse dose volume optimization algorithm was used to generate plans with various smooth values, and the optimization conditions were the same as the original clinical plans. Key dosimetric metrics and total dwell time differences were comparatively analyzed. The applicators were intentionally subjected to position errors (0.2-1.0 cm) in 6 directions (left-right, anterior-posterior, head-foot), and the effect of various smooth values on plan quality and robustness was assessed. There were 133 plans per case and 2 660 plans for 20 patients. The results were statistically analyzed using the Wilcoxon signed-rank nonparametric test.Results:As the smooth value was increased, the modulation factor was gradually decreased and the D 2 cm3 of the bladder and rectum was increased. Plans with smooth values of 0.25, 0.50, 0.75, 1.00 had modulation factors of 0.72±0.09, 0.63±0.08, 0.55±0.08, 0.51±0.06, respectively, lower than 0.75±0.05 of the plan with the smooth value of 0.00, and all differences were statistically significant ( P=0.004, 0.002, 0.002, 0.002). The bladder D 2 cm3 of plans with smooth values of 0.50, 0.75, 1.00 were (475.4±41.0) cGy, (483.7±46.2) cGy, and (489.0±46.8) cGy, respectively, higher than (469.8±41.8) cGy of the plan with the smooth value of 0.00, with statistically significant differences (all P=0.002). The rectum D 2 cm3 of plans with smooth values of 0.50 and 0.75 plans were (413.2±93.3) cGy and (418.6±96.4) cGy, both higher than (410.2±91.5) cGy of the plan with the smooth value of 0.00, with statistically significant differences ( P=0.006, 0.010). When positional errors were introduced, the high risk clinical target volume (HR-CTV) D 90% was close for different smooth plans at most positional errors, and the differences were not statistically significant. The organs at risk D 2 cm3 of plans with the smooth value of 0.00 was lower than those of plans with other smooth values, and for the bladder and rectum, the differences were statistically significant at most positional errors (all P<0.01). Conclusions:The dwell time deviation constraint parameter exerts significant effect on the plan quality, and the smaller the value of the constraint parameter, the higher quality of the plan. The dwell time deviation constraint parameter has slight impact on the positional error robustness of dosimetric indices of targets and key organs at risk.

Study of the optimal thresholds of gamma passing rate in VMAT plan verification for cervical cancer / 中华放射肿瘤学杂志

Objective To investigate the optimal thresholds of the passing rate with different gamma measurement criteria (percent dose difference/DTA) based on the Delta 4 three-dimensional dosimetric verification system in the verification of volumetric modulated arc-therapy (VMAT) plan for cervical cancer.Methods Thirty clinically-approved dual-arc VMAT plans using the RapidArcTM (Varian Medical Systems Inc.) for cervical cancer were randomly selected.The gamma analysis and dose-volume histogram (DVH) evaluation were performed using Delta 4.All the plans were classified according to the following two criteria:1.If the absolute percentage dose errors of all specific dosimetry indices on the DVH were less than 5％,the plan was regarded as clinically acceptable.2.If the gamma passing rate was 90％ or 95％ under the criteria of 2％/2 mm and 3％/3 mm,the plan was regarded as acceptable.The sensitivity and specificity analyses were conducted based on the classification results and the receiver operating characteristic (ROC) curve was plotted.By calculating the Youden Index,the optimal thresholds under different Gamma criteria (global and local 2％/2 mm and 3％/3 mm) were investigated.Finally,the ability of distinguishing the plan was clinically acceptable or not between the conventional and optimal thresholds was quantitatively compared according to the sensitivity and specificity analyses.Results The optimal thresholds under the global 3％/3 mm and 2％/2 mm criteria were 98.3％ and 87.05％;and 97.55％ 、86.05％ for the local gamma analysis.Compared with the conventional thresholds,the sensitivity of the optimal thresholds was 0.93 by using the global and local gamma analyses under the 3％/3 mm criterion.Under the 2％/2 mm criterion,the sensitivity of the optimal thresholds was 0.65 and the specificity was 0.49 by using the global gamma analysis.The sensitivity was 0.7 and the specificity was 0.46 by using the local gamma analysis,suggesting that the sensitivity and the specificity were more balanced under the 2％/2 mm criterion.Conclusions Application of the optimal thresholds in the verification of VMAT plans can maintain the balance between the sensitivity and specificity,prevent the harm of clinically unacceptable plans to patients to certain extent and reduce the probability of increasing the daily work load for physicists due to the misjudgement of clinically acceptable plans.

The optimal gamma passing rate thresholds of IMRT dosimetric verification in the treatment of esophageal cancer / 中华放射医学与防护杂志

Objective To investigate the optimal gamma passing rate of intensity-modulated radiotherapy (IMRT) dosimetric verification in the treatment of esophageal cancer using a three-dimensional dose verification system EDoseTM.Methods Twenty five esophageal cancer patients treated by 7-field IMRT were retrospectively reviewed.Measured dose distribution were reconstructed on CT image and evaluated by gamma analysis and DVH metrics using the EDoseTM system.Plans with DVH metrics dose difference ＜ 5％ or with gamma passing ＞ 90％ under 3％/3 mm criteria were accepted.The optimal gamma passing rate for criteria of 5％/3 mm,3％/3 mm,2％/2 mm were investigated by drawing the receiver operating characteristic (ROC) curves and calculating the Youden Index.The sensitivity and specificity of the these optimal thresholds in the plan verification were also analyzed.Results The optimal thresholds for global gamma indices with 5％/3 mm,3％/3 mm,2％/2 mm were 98.66％,94.84％,78.56％,respectively.In the 90％ common threshold,The sensitivity and specificity for common 90％ threshold and optimal threshold under 3％/3 mm criteria were 0.17 vs.0.85 and t 0.84 vs.0.27,respectively.The sensitivity and specificity were 0.89,0.65 and 0.23,0.47 for optimal thresholds under 5％/3 mm and 2％/2 mm criteria,respectively.Conclusions The sensitivity of optimal threshold gamma passing rate improved significantly compared with the common threshold (90％) at 3％/3 mm criteria.,The sensitivity and the specificity were more balanced at the 2％/2 mm criteria compared with those at 3％/3 mm criteria.

Sphingosine kinase 1 enhances the proliferation and invasion of human colon cancer LoVo cells through up-regulating FAK pathway and the expression of ICAM-1 and VCAM-1 / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effects of sphingosine kinase 1 (SphK1) on the proliferation, migration and invasion of human colon cancer LoVo cells, and to explore the related mechanisms.</p><p><b>METHODS</b>Human colon cancer LoVo cells were divided into three groups: phorbol 12-myristate 13-acetate (PMA) was used to induce the activation of SphK1 in the PMA group, N,N-dimethylsphingosine (DMS) used to suppress the activity of SphK1 in DMS group, and the cells treated with equal amount of 0.9 % NaCl instead of drugs served as the control group. The activity of SphK1 was assayed by autoradiography, the cell proliferation was assessed by MTT assay, cell migration and invasion were examined by Boyden chamber assay, concentrations of sICAM-1 and sVCAM-1 were assayed by ELISA, and RT-PCR and Western blot were used to evaluate the mRNA and protein expression in the cells.</p><p><b>RESULTS</b>The activity of SphK1 was efficiently induced by PMA and significantly suppressed by DMS. PMA induced cell proliferation in a time- and dose-dependent manner. On the contrast, DMS suppressed cell proliferation in a time- and dose-dependent manner. After treating with PMA, the number of migrating and invasing cells were increased to 143.36 ± 8.73 and 118.46 ± 6.25, significantly higher than those of the control group (75.48 ± 6.12 and 64.19 ± 5.36). After treating with DMS, the number of migrating and invasing cells were decreased to 38.57 ± 3.24 and 32.48 ± 4.27, significantly lower than those of the control group (P < 0.01). The relative expression levels of FAK, ICAM-1 and VCAM-1 mRNA in the PMA group were 0.82 ± 0.06, 0.74 ± 0.05 and 0.89 ± 0.09, and those in the DMS group were 0.23 ± 0.02, 0.26 ± 0.03 and 0.37 ± 0.04, with significant differences between the PMA, DMS and control groups (P < 0.01). Compared with the control group, the relative expression levels of FAK and p-FAK proteins in the PMA group (0.52 ± 0.06 and 0.51 ± 0.06) were significantly elevated, and those of the DMS group (0.20 ± 0.03 and 0.09 ± 0.02) were significantly decreased. In addition, the concentrations of sICAM-1 and sVCAM-1 were significantly elevated with the activation of SphK1. On the contrary, those of the DMS group were significantly reduced with the suppression of SphK1 (Both P < 0.01).</p><p><b>CONCLUSIONS</b>SphK1 may enhance the proliferation, migration and invasion of colon cancer LoVo cells through activating FAK pathway and up-regulating the expression of ICAM-1 and VCAM-1.</p>

Effect of sphingosine kinase 1 on the apoptosis, migration and invasion of colon cancer HT-29 cells and its molecular mechanisms / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of sphingosine kinase 1 (SphK1) on the proliferation, apoptosis, migration and invasion of colon cancer TH-29 cells and to explore its molecular mechanisms.</p><p><b>METHODS</b>Phorbol 12-myristate 13-acetate (PMA) was used to induce the activity of SphK1 and N, N-dimethylsphingosine (DMS) was used to suppress the activity of SphK1. Cell prolieration and apoptosis were detected by MTT assay and flow cytometry, respectively. The migration and invasion capabilities of the cells were assessed in Transwell chambers. The activity of SphK1 was assayed by autoradiography. Western blot was used to evaluate the protein expression of SphK1, p38, phosphorylated p38 (p-p38) and SAPK/JNK.</p><p><b>RESULTS</b>PMA and DMS were able to induce and suppress the activity and protein expression of SphK1 in a time-dependent manner, respectively. PMA enhanced and DMS suppressed the cell viability in a time- and dose-dependent manner. Being treated with 100 nmol/L PMA or 50 µmol/L DMS for 0, 6, 12, 24 h, the cell apoptosis rates of PMA group were (9.35 ± 0.84)%, (7.61 ± 0.48)%, (5.53 ± 0.76)% and (0.56 ± 0.33)%, contrastly, that of DMS group were (9.18 ± 0.94)%, (12.06 ± 1.41)%, (19.80 ± 2.36)% and (31.85 ± 3.60)%, respectively. Compared with the control group, the cell migration and invasion capabilities of the PMA group were significantly enhanced, and that of the DMS group were significantly suppressed. The migration cell number of control, PMA and DMS groups were 68.75 ± 6.15, 109.33 ± 11.63 and 10.83 ± 2.48, the invasion cell number of control, PMA and DMS groups were 55.42 ± 4.50, 90.58 ± 7.06 and 9.58 ± 2.39, respectively. With the elevating activity and expression of SphK1, the protein expressions of p38, p-p38 and SAPK/JNK were strikingly suppressed. On the contrary, after treating with DMS the protein expressions of p38, p-p38 and SAPK/JNK were enhanced.</p><p><b>CONCLUSIONS</b>SphK1 potently enhances the prolieration, migration and invasion of colon cancer HT-29 cells, meanwhile suppresses the cell apoptosis. The suppressing of the p38 and SAPK/JNK signalling pathways may be one of its molecular mechanisms.</p>

Vasoactive intestinal peptide expression and its clinical significance in gastric adenocarcinoma / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the expression of vasoactive intestinal peptide (VIP) in gastric adenocarcinoma, and to evaluate the correlation of VIP level with clinical pathologic parameters.</p><p><b>METHODS</b>The level of VIP in sera from gastric adenocarcinoma patients and healthy people was investigated by ELISA. Moreover, the differential gene expression between gastric adenocarcinoma, gastric dysplasia, and the corresponding normal gastric mucosa were determined by RT-PCR. Western Blot was also used to measure the expression of VIP in the gastric adenocarcinoma and the normal gastric mucosa.</p><p><b>RESULTS</b>The serum level of VIP was (5.794 +/- 0.014) ng/ ml in normal control and was (14.437 +/- 0.825) ng/ml in gastric adenocarcinoma patients, showing significant difference (P < 0.05). Meanwhile,the V/B of gastric adenocarcinoma tissues was greater than that of gastric dysplasia and the corresponding normal gastric mucosa (P <0.01), the values of V/B were 1.5261 +/- 0.3028, 0.9334 +/- 0.2872,and 0.9051 +/- 0.2794, respectively. The values of V/B between normal gastric mucosa and gastric dysplasia were not different significantly (P > 0.05). There were significantly negative correlation between the VIP mRNA expression of the differentiation degree of tumor (P < 0.05). The VIP mRNA expression was higher in gastric adenocarcinoma with lymph node metastasis than that without lymph node matastsis (P < 0.05). The VIP protein expression of the gastric adenocarcinoma tissues was greater than that of normal control.</p><p><b>CONCLUSION</b>This findings provide a direct evidence to support the possibility that VIP play a cofactor role in the pathogenesis of gastric adenocarcinoma.</p>