The application of precision medicine in cancer treatment is becoming increasingly common as a result of the continuous advancement in basic research and physical techniques.The revolution of radiotherapy techniques, development of multimodal imaging technology, application of biological target dose carving and adaptive radiotherapy, availability of big data-based radiotherapy planning systems, and selection of chemotherapy regimen have all made the treatment of nasopharyngeal carcinoma increasingly precise.The growing interaction between laboratory research and clinical practice not only underscores the importance of translational medicine, but also prompts the development of biological immunotherapy and screening of prognostic factors.As a result, these changes mark the beginning of a new era for the diagnosis and treatment of nasopharyngeal carcinoma.This review provides a summary from 61 articles on the current progress in translational study and clinical application of precision medicine in nasopharyngeal carcinoma.

ObjectiveTo study of the impact on dose distribution by electron width of energy spectrum and angular distribution using Monte Carlo simulation.MethodsThe simulated electron energy spectrum and angular distributions was as the input parameters and percentage depth dose (PDD) and offaxis curves were simulated by a modified PENELOPE code package. Results PDD and off-axis dose distribution curves are almost the same and are not sensitive to energy spectrum width and angular distribution with the exception of energy spectrum width of 2.5 MeV with obviously different curves.ConclusionsIn the situation of clinical treatment,spectrum and angular distributions can be ignored when their width are not very large.It is helpful to save about 9％ time by using monoenergy beams in treatment planning system development.

Objective To calculate the effects of thermoplastic mask on X-ray surface dose.Methods The BEAMnrc Monte Carlo Code system, designed especially for computer simulation of radioactive sources, was performed to evaluate the effects of thermoplastic mask on X-ray surface dose.Thermoplastic mask came from our center with a material density of 1.12 g/cm2. The masks without holes,with holes size of 0. 1 cm× 0. 1 cm, and with holes size of 0. 1 cm × 0. 2 cm, and masks with different depth (0.12 cm and 0.24 cm) were evaluated separately. For those with holes, the material width between adjacent holes was 0. 1 cm. Virtual masks with a material density of 1.38 g/cm3 without holes with two different depths were also evaluated. Results Thermoplastic mask affected X-rays surface dose. When using a thermoplastic mask with the depth of 0. 24 cm without holes, the surface dose was 74. 9% and 57.0% for those with the density of 1.38 g/cm3 and 1.12 g/cm3 respectively. When focusing on the masks with the density of 1.12 g/cm3, the surface dose was 41.2% for those with 0.12 cm depth without holes;57.0% for those with 0. 24 cm depth without holes;44. 5% for those with 0. 24 cm depth with holes size of 0.1 cm ×0.2 cm;and 54.1% for those with 0.24 cm depths with holes size of 0.1 cm ×0.1 cm.Conclusions Using thermoplastic mask during the radiation increases patient surface dose. The severity is relative to the hole size and the depth of thermoplastic mask. The surface dose change should be considered in radiation planning to avoid severe skin reaction.

ObjectiveTo study the using of cerrobase as the compensation material in the intensitymodulated radiation therapy (IMRT) implementation and impact factors.MethodsWith therapy planning system (TPS) exported the radiation field intensity file (Dicom RT),through measuring the attenuation coefficient of cerrobase,to calculate the processing depth of AUTIMO 3D CNC corresponding for Dicom RT files at each pixel,then using the processed foam casting of Cerrobase,produced the required IMRT compensator.Through the MATRIXX testing the IMRT compensator in clinical implementation.At the same time we compared the MU of using multi-leaf collimator (MLC) and Cerrobase IMRT compensator for 10patients.ResultsWith cerrobase compensation IMRT can get similar dose or dose distribution to dose produced by TPS for point or plane dose,error is within 5％.To comparison with MLC,using cerrobase compensator has fewer treatment times ( (4.44±0.39) min:(5.71±0.57) min (t =10.82,P =0.000) )and fewer MU (462.5 ± 65.8) MU:(524.5±99.6) MU(t=3.14,P=0.012) ).Conclusions Comparison with MLC IMRT,the cerrobase compensation technique has an important application value with its unique advantages.This research provides an implemented method of IMRT radiotherapy for the primaryhospital.

ObjectiveTo analyze the role of postmastectomy radiotherapy in different molecular subtypes of breast cancer patients with Stage T1 -T2 and one to three positive axillary nodes. MethodsA total of 436 breast cancer patients with T1 -T2 and one to three positive axillary lymph nodes treated with mastectomy and axillary dissection were retrospectively analyzed. Patients were grouped as the following four subtypes:Luminal A, Luminal B, Her2+ and triple-negative. The local recurrence (LR), distant metastasis ( DM ), disease free survival (DFS) and overall survival (OS) rates were compared between paitents with or without radiotherapy in univariate analyses. Multivariate analyses for LR were performed. Results The follow-up rate was 86. 0％. In patients with Luminal A subtype, radiotherapy decreased the 5-year LR rate (4.6％ vs 15.8％ ,x2 =5.74,P=0.017) but had no influences on DM, DFS or OS rates (17.2％ vs 19.7％,x2 =0. 17,P=0.682;77.0％ vs 67. 1％ ,x2 =1.99,P=0. 158 or87.4％:85. 5％ ,x2 =0. 12,P=0. 733 ). In patients with Luminal B subtype, radiotherapy decreased the 5-year LR rate (3.7％ vs 12. 1％,x2 =4. 13, P =0. 042), increased DFS and OS ( 84. 0％ vs 57.6％ ( x2 =14.61, P =0. 000) and 91.4％ vs 70. 7％ ( x2 =11.87, P =0. 001 ), but had no influence on DM ( 12. 3％ vs 22. 2％, x2 =2. 97, P =0. 085).In patients with Her2+ subtype, radiotherapy decreased the 5-year LR rate (5. 6％ vs 31.0％ ,x2 =4. 31,P=0. 035) , increased DFS (61. 1％ vs 13. 8％ ,x2 =11.44,P=0.001 ) ,but had no influence on DM and OS (27.8％ vs 41.4％, x2 =0. 89, P =0. 345 and 66. 7％ vs 48. 3％, x2 =1.52,P =0. 218 ). In patients with triple-negative subtype, radiotherapy had no influence in LR, DM, DFS or OS (8. 7％ vs 26. 1％ ,x2 =2.42,P=0.120;39.1％ vs47.8％,x2=0.35,P=0.552;52.2％ vs 26.1％ , x2 =3. 29, P =0. 070 or 65.2％ vs 56. 5％ ,x2 =0. 37 ,P =0. 546). Tumor size and radiotherapy were independent prognostic factors for LR rate in multivariate analyses ( x2 =4. 76, P =0. 029 and x2 =8.06, P =0. 005 ). ConclusionsFor patients with stage T1 -T2 and one to three positive axillary nodes, patients with all molecular subtypes except triple-negative can benefit from postmasteetomy radiotherapy.

Objective To compare the local control and survival rates of hyperfractionated radiotherapy plus concurrent chemotherapy with hyperfractionated radiotherapy alone in the treatment of stage Ⅲ-Ⅳ nasopharyngeal carcinoma (NPC).Methods Between December 1992 and December 1995, 150 NPC patients were randomized into hyperfractionated radiotherapy plus concurrent chemotherapy (R+C) and hyperfractionated radiotherapy alone (R alone) groups. Radiotherapy were similar in the two groups: 1.2 Gy/f, twice a day. Chemotherapy was given to R+C patients before and during the course of radiotherapy. Results The overall 5-year survival (OS), disease-free survival and distant metastasis-free survival rates were 57.3%, 55.9% and 55.9% . The 5-year survival rates of the R+C and R alone groups were 64.0% and 50.7%, with the difference statistically significant (P=0.037). One patient in the R+C group and 5 patients in the R alone group developed nasopharyngeal recurrence and the corresponding 5-year local control rates were 98.7% and 93.4%. The acute mucosal reaction in the R+C patients was severer than that of the R alone, but well tolerated and did not develop any severe complications. Conclusions Hyperfractionated radiotherapy plus concurrent chemotherapy can improve the local control and survival in patients with stage Ⅲ-Ⅳ nasopharyngeal carcinoma with well tolerated mucosal reactions. Chemotherapy gives greater benefit on the survival of stage Ⅳ patients.

The purpose of tumor staging is to guide treatment, and the treatment for a certain stage should be adjusted based on the changes in disease condition, in order to facilitate better control of tumor. Therefore, the treatment of liver cancer requires follow-up and re-staging to develop better treatment regimens for patients, especially the opportunity for cure. Surgical resection is not suitable for large hepatocellular carcinoma confined to the liver, and after embolization chemotherapy combined with radiotherapy for tumor regression and downstaging, some patients may undergo surgical resection, and the incurable tumor can thus be cured. For liver cancer patients with portal vein tumor thrombus, surgical resection can be performed after tumor thrombus is reduced by neoadjuvant radiotherapy, and the patients undergoing neoadjuvant radiotherapy have a significant increase in survival time than those not undergoing neoadjuvant radiotherapy. Large hepatocellular carcinoma can be downstaged to small hepatocellular carcinoma after multimodality therapy, and then stereotactic radiotherapy or radiofrequency ablation can help to achieve radical treatment. There is an increasing number of clinical reports of radiotherapy for liver cancer downstaging, with a gradual increase in evidence-based level, and thus it holds promise for clinical application.

Objective To investigate the possibility of chloroquine radiosensitization of esophageal cancer cell line TE-1 and its further mechanism.Methods Effect of chloroquine on cell viability of TE-1 cells was determined by MTT method.Expression of LC3,Beclin-1 and formation of acidic vesicular organelles (AVOs) were determined by Western blot,and fluorescence staining with Lyso-Tracker Red DND-99,respectively.Clonogenic survival of TE-1 cells was examined by clonogenic forming assay.Results Chloroquine showed dose-dependent inhibition of TE-1 cell growth,and its values of IC50 and IC10 were (72.33 ± 5.28) and (15.42 ± 3.33) μmol/L,respectively.The expression of Beclin-1 and LC3-Ⅱ/Ⅰ markedly increased in irradiated TE-1 cells.The addition of chloroquine with IC10concentration significantly reduced the fluorescence and intensity of AVOs accumulation in the cytoplasm of TE-1 cells.Clonogenic survival fraction decreased obviously,in TE-1 cells with addition of chloroquine after radiation and the value of SERD0 was 1.439.Conclusions Chloroquine could radiosensitize esophageal cancer cells by blocking autophagy-lysosomal pathway and be used as a potential radiosensitizing strategy.

OBJECTIVE To study the radiose-nsitization by Topotecan on human nasopharyngeal carcinoma in nude mice. METHODS ①To study the maximum tolerance dose of TPT and detect the effective rate of TPT and RT on nude mice. ② Plan of radiosensitization practice:53 nude mice xenografts were distributed to 5 groups:RT 20 Gy group,RT 40 Gy group,TPT 12.5 mg/kg group,TPT 12.5 mg/kg+RT 20 Gy group and the controlgroup. After treatment,the volume of tumors were measured every 3 days in order to value the effective rate [complete remission(CR) + partial remission(PR) ]and regrowth delay time(TGD) and to fit the growth curve. RESULTS This study showed that the effective rates had significant difference among RT20 Gy+TPT 12.5 mg/kg group,RT20 Gy group and TPT12.5 mg/kg group,while that of RT20 Gy +TPT 12.5 mg/kg group and RT40 Gy group had no statistical difference. SER reached to 1.34. CONCLUSION Topotecan has been shown a radiosensitizing effect on human nasopharyngeal carcinoma in vivo.

Objective To investigate the dose and mechanical properties of medical electron linear accelerators in grass-roots radiotherapy units in Sichuan Province,China via sampling and inspection.Methods A total of eight radiotherapy units in Sichuan Province were selected by sampling,and the tests were performed for the dose and mechanical properties of the medical electron linear accelerators in use.Among these accelerators,there were 5 imported accelerators and 3 domestic accelerators.The test items and methods were determined according to the requirements in GB15213-94.Results Among the 14 test items,the items related to the flatness,symmetry,and overlap of radiation field.The other tests of dose accuracy and mechanical precision achieved good results.Conclusions There is a need to strengthen the daily quality control work for dose and mechanical accuracy of medical electron linear accelerators in grass-roots radiotherapy units in Sichuan Province and perfect the allocation of professional equipment and personnel and training of related personnel.With the support of Sichuan Radiotherapy Quality Control Center,quality control supervision and guidance should cover the whole province.