ABSTRACT
Objective To study the efficacy of late course accelerated fractionation(LCAF) radio- therapy in the treatment of nasopharyngeal carcinoma(NPC).The end-po s were local control,radiation-in- duced complications,factors influencing survival.Methods From December 1995 to April 1998,178 NPC patients were admitted for radiation treatment.The radiation beam used was ~(60)Co?or 6 MV X-ray.For the first two-thirds of the treatment,two daily fractions of 1.2 Gy were given to the primary lesion ,with an interval of≥6 hours,5 days per week to a total dose of 48 Gy/40 fractions,over a period of 4 weeks.For the last one third of the treatment,i.e.beginning from the 5th week,an accelerated hyperfractionation schedule was carried out.The dose per fraction was increased to 1.5 Gy,2 fractions per day with an interval of≥6 hours,the total dose for this part of the protocol was 30 Gy/20 fractions over 2 weeks.Thus the total dose was 78 Gy in 60 fractions in 6 weeks.Results All patients completed the treatment.Acute mucosi- tis:none in 2 patients,Grade 1 in 43,Grade 2 in 78,Grade 3 in 52,and Grade 4 in 3 patients.Local control rate:the 5-year nasopharyngeal local control rate was 87.7%,and the cervical lymph node local control rate was 85.7%.The 5-year distant metastasis rate was 26.1%,and 5-year survivals was 67.9%. Sixteen patients had radiation-induced cranial nerve palsy.Conclusions With this treatment schedule, patient's tolerance is good,local control and 5 year survivals are better than control groups of conventional fractionation and hyperfractionation radiotherapy.Radiation-related late complication does not increase.Ran- domized clinical trials are being carried out to further confirm the efficacy of LCAF for nasopharyngeal carci- noma.
ABSTRACT
Objective To evaluate whether Ly294002,suppressing phosphatidylinositol 3 kinase (PI3K)/AKT survival signaling pathway,can change the sensitivity of breast cancer cells to radiotherapy. Methods Breast cancer cultured MCF7 cells treated with:radiation alone;Ly294002;or the combination of radiation and Ly294002.The inhibition of PI3K/AKT by Ly294002 was confirmed by Western blot.Clo- nogenic assay was used quantitatively to measure the mitotic cell death,and caspase-3 assay was used to e- valuate apoptosis.Results 1.Ly29400 could partially inhibit phosphorylated AKT but not radiation,the combination of both could enhance the inhibition of phosphorylated AKT,2.Timing of exposing cells to Ly294002 had some impact on clonogenic survival by radiation,one hour pre-radiation and 10 days post-ra- diation exposing to Ly294002 could maximally sensitize the cells to irradiation,3.Ly29400 combined with radiation could synergistically enhance mitotic death and apoptosis of MCF7 cells,with SER of SF_4 and D_0, being equal to 1.25 and 1.42.Conclusions PI3K/AKT pathway may be a potential target for enhancing the response of breast cancer cells to radiotherapy.