Emerging clinical evidence revealed that postoperative adjuvant chemoradiotherapy (CRT) could improve the clinical outcome for resected head and neck squamous cell carcinoma in high-risk patients. The irradiation targets and doses should be determined by the primary tumor site, clinical stage, pathology reports, and the evaluation of postoperative imaging. Adjuvant concurrent CRT with cisplatin is the current standard treatment for high-risk postoperative head and neck squamous cell carcinoma patients. However, the effect of concurrent CRT with other chemotherapeutic agents and (or) epidermal growth factor receptor (EGFR) monoclonal antibody in these patients is inconclusive. Human papillomavirus (HPV)-positive oropharyngeal cancer has the unique biological characteristics, and the indications and treatment models of postoperative adjuvant CRT for these patients are still unclear. Further study is needed.

Microenviroment hypoxia is one of the common phenomenon in cancer,studies have indiacat-ed that hypoxia induces genetic instability via activating many DNA danlage-repair signal pathways,which asso-ciates with tumor invasion and resistance and chemi-radiotherapy resistivity.Here,we overview three main DNA damage-repair pathways:mismatch repair,homologous recombination and non-homologous end joining,and how hypoxia influences their mechanisms.

Patients with ataxia-telangiectasia ( A-T) syndrome were charachaterized by profound hypersensitivity to ionizing radiation in clinic. Many studies have shown that this hypersensitivity possibly attributed to ATM gene whose critical compartment was ATM kinase. So inhibitors of the ATM kinase such as caffeine, pentoxifylline, methyl xanthines and 7-hydroxystaurosporine (UCN-01) were developed and have achieved a few encouraging results in basic and clinical stuides.

Objective To investigate whether chromosome induced aberrations scored with fluorescence in situ hybridization (FISH) predict the radiosensitivity of human tumor cell lines. Methods Three human cell lines with different radiosensitivities(nasopharyngeal cell line CNE, lung adenocarcinoma cell line SPC, and breast adenocarcinoma cell line MCF 7) were used for clonogenic assay. Cells were irradiated with a dose of 1～8?Gy. Radiation induced aberration in a single chromosome (number 8) was measured at 24?h after irradiation of 2, 4 and 6?Gy.Results Radiation induced aberration in chromosome 8 reflected the radiosensitivity in CNE, SPC and MCF 7 cells 24 h after irradiation. It was associated with survival fraction at 2?Gy (r=0.96). Conclusion These results suggest that the radiation induced chromosome aberrations in interphase measured by FISH be a considerable promise for prediction of radiosensitivity in tumor cells.

Objective To evaluate the prognosis for patients with squamous cell carcinoma of cervical lymph node metastases from an unknown primary site who had different clinical stages and were irradiated to different fields. Methods The clinical date of 60 patients with cervical lymph node metastatic squamous cell carcinoma from an unknown primary site(no including patients with supraclavicular node metastases) were retrospectively analyzed. Results The overall 5-year survival rates(OSR) was 68.5%, the OSR of patients with N 1,N 2 and N 3 stage were 100%, 68.0% and 40.9% respectively(? 2=7.29,P=0.026). The OSR of patients with one lateral neck, whole neck and large fields irradiation were 66.5%, 74.5% and 54.6% respectively(? 2=1.38,P =0.501). The Cox proportional hazard model showed that clinical stages of cervical lymph node had an significant effect in patients survival(P=0.032). The 5-year local control rates(LCR) 65.6%, the LCR of patients with N 1,N 2 and N 3 stage were 100%, 63.2% and 34.6% respectively(? 2=5.51, P=0.064). The LCR of patients with one lateral neck, whole neck and large fields irradiation were 87.6%, 51.0% and 72.7% respectively(? 2=2.55, P =0.279). The 5-year subsequent appearance rates of occult primary cancer(SAR) was 21.2%, the SAR of patients irradiated by small(one lateral neck or whole neck) and large fields were 23.3% and 12.5% respectively(? 2=0.52, P =0.469). Conclusions The clinical stages of cervical lymph node is an important prognostic factor for survival and the local control rates has a decreasing trend as the stage increases. The subsequent appearance rates of occult primary cancer of patients irradiated by small fields has a higher trend than its of patients irradiated by large fields, but the control rates and survival rates have no significant difference in different fields irradiated.

(0.05)). Multivariate analysis revealed that adjuvant radiotherapy and histology of tumor significantly affected the prognosis(P=(0.045) and P=(0.009), respectively). Whereas loco-regional control was only significantly affected by adjuvant radiotherapy(P=(0.000)). CONCLUSION: Adjuvant radiotherapy and histology of tumor are the important prognostic factors in the rectal cancer patients after treatment with multimodality therapy based on surgery.

Objective To compare the agreement among Chinese 1992, 2008 and UICC 2010 staging systems of nasopharyngeal carcinoma (NPC) and evaluate their predictive value of radiotherapeutic prognosis.Methods 347 NPC patients without distant metastasis treated in our hospital from 2000 to 2005 were retrospectively analyzed.Every patient was categorized into T, N, and clinical stage by Chinese 1992, 2008 and UICC 2010 staging systems, respectively.Kappa value was used to evaluate the agreement among three systems.Kaplan-Meier method was used to analyze the 5-year overall survival (OS), local-free survival (LFS) and distant metastasis-free survival (DMFS), the difference between subgroup was tested by Logrank.Results The agreement of clinical stage, T and N stage between Chinese 2008 and UICC 2010 staging system was better than that of them compared to 1992 staging system, Kappa value were 0.700、0.881 and 0.722.The agreement of T stage was better than N and clinical stage among these three staging system.The difference of OS between stageⅢ and stage Ⅳ was significant in Chinese 2008 and UICC 2010 staging system (χ2=4.48,P=0.034;χ2=8.88,P=0.003), and with no different in 1992 staging system (χ2=0.40,P=0.526).There was no significant difference of LFS between T1 and T2,T2 and T3,T3 and T4 in all staging systems (χ2=1.85,0.53,0.50,P=0.174,0.467,0.479;χ2=1.25,2.10,1.99,P=0.264,0.148,0.159;χ2=0.77,0.60,0.87, P=0.381,0.441,0.350).There were no significant differencesin 1992 staging system, while there was significant differences of DMFS between N1 and N2, N2 and N3 in 2008 stage system, N1 and N2 in UICC 2010 stage system.Conclusions The predictive value of Chinese 2008 and UICC 2010 staging system for prognosis were similar, and were better than that of 1992 staging system in NPC.

Objective To study three contouring approaches of the bowel and evaluate the bowel dose volume with cervical cancer patient.Methods Twelve patients were selected,prescribed dose 45 Gy/ 25f.For each patient we contoured the bowel according to three different definitions:bowel loops,bowel bag and peritoneal space.Then we generated three rival plans each considering a different bowel definition and to evaluate dose differences of the HI,CI of PTV and D D V5-V45 of bowel loops with paired t-test.Results Comparison between BL and BB plan,Dmax,HI and CI of PTV,V5-V45 of bowel loops were not significantly different (P =0.171,0.076,0.192,P =0.315-0.855),D of PTV and Dmax of bowel loops had difference (P=0.017,0.038).Comparison between BL and PS plan,Dmax,D HI and CI of PTV and Dmax of bowel loops had differences (P=0.033,0.044,0.046,0.041,0.013),V5-V45 of bowel loops were not significantly different (P=0.416-0.977).If the bowel loops V40 ≤ 15％,and bowel bag and peritoneal space V40≤20％.Conclusions All definitions provided a very similar dose volume of bowel loops.Taking into account HI and CI of PTV and max dose of bowel loops,BB seems better than PS.

Objective To investigate the difference in normal tissue complication probability (NTCP) of lower cranial nerves (LCNs) between target volumes recommended by Radiation Therapy Oncology Group (RTOG) and China in intensity-modulated radiotherapy (IMRT) for T1-2 nasopharyngeal carcinoma (NPC),and to provide the evidence of dose-volume effect for the protection of LCNs in IMRT for NPC.Methods A total of 20 patients with T1-2 NPC who were treated from 2013 to 2015 were enrolled,and LCNs were delineated on CT images.Target volume delineation and treatment plan designing were performed according to the method recommended by RTOG0225 (RTOG target volume delineation method) or the Chinese Working Committee for Clinical Staging of NPC in 2010 (Chinese target volume delineation method),and the differences in the dose to LCNs and NTCP were calculated.Results In the RTOG and Chinese methods for target volume delineation,Dmax to the left and right LCNs was 7 450±273 cGy/7294±309 cGy and 7 361± 160 cGy/7 190±395 cGy,respectively (P=0.018 and 0.042),Dmean was 6735±285 cGy/6 660±333 cGy and 6 446±429 cGy/6 299±467 cGy,respectively (both P=0.000),and the NTCP was 60％±10％/57％±13％ and 51％±15％/45％±17％,respectively (both P=0.000).Conclusions It is feasible to precisely delineate target volume with the LCNs as a routine OAR and predict NTCP in IMRT for T1-2 NPC.The NTCP of the LCNs is closely associated with target volume dose and irradiated volume.The dose to the LCNs and NTCP determined by the Chinese target volume delineation method are significantly lower than those determined by the RTOG method.

Objective To investigate the effect of human lung cancer-associated fibroblasts (CAF) on the radiosensitivity of lung cancer cells when CAF is placed in direct contact co-culture with lung cancer cells.Methods Human lung CAF was obtained from fresh human lung adenocarcinoma tissue specimens by primary culture and subculture and was then identified by immunofluorescence staining.The CAF was placed in direct contact co-culture with lung cancer A549 and H1299 cells,and the effects of CAF on the radiosensitivity of A549 and H1299 cells were evaluated by colony-forming assay.Results The human lung CAF obtained by adherent culture could stably grow and proliferate,and it had specific expression of α-smooth muscle actin,vimentin,and fibroblast activation protein,but without expression of cytokeratin-18.The plating efficiency (PE,％) of A549 cells at 0 Gy irradiation was (20.0 ± 3.9) ％ when cultured alone versus (32.3 ± 5.5) ％ when co-cultured with CAF (t =3.16,P ＜ 0.05),and the PE of H1299 cells at 0 Gy irradiation was (20.6 ± 3.1) ％ when cultured alone versus (35.2 ± 2.3) ％ when co-cultured with CAF (t =6.55,P ＜0.05).The cell survival rate at 2 Gy irradiation (SF2) of A549 cells was 0.727 ±0.061 when cultured alone versus 0.782 ± 0.089 when co-cultured with CAF (t =0.88,P ＞ 0.05),and the SF2 of H1299 cells was 0.692 ±0.065 when cultured alone versus 0.782 ± 0.037 when co-cultured with CAF (t =2.08,P ＞0.05).The protection enhancement ratios of human lung CAF for A549 cells and H1299 cells were 1.29 and 1.25,respectively.Conclusions Human lung CAF reduces the radiosensitivity of lung cancer cells when placed in direct contact co-culture with them,and the radioprotective effect may be attributed to CAF promoting the proliferation of lung cancer cells.