| Background and ObjectiveEsophageal cancer is one of the common malignant tumors in the world.The most common pathological type in China is squamous cell carcinoma.Due to the insidious onset,about 70%of patients have reached the middle and advanced stages at the time of diagnosis,losing the chance of radical surgery,and the prognosis is poor.Radiation therapy is one of the most important treatment methods for advanced esophageal cancer.For patients with inoperable locally advanced esophageal cancer,the currently commonly used radiotherapy mode is sequential boost of intensity-modulated radiotherapy,which needs a reformulation treatment plan during the radiotherapy.The treatment plan makes it difficult to guarantee the homogeneity of the dose in the target area.At the same time,the increase in the number of treatments increases the positioning error and the workload of the physician,and prolongs the length of patient stay and increases the cost of hospitalization.There are many limitations in the implementation process.Simultaneous integrated boost intensity-modulated radiotherapy(SIB-IMRT)is an unconventional radiotherapy mode that is increasingly used in clinical practice in recent years.It can set different irradiation doses to different areas in the same target area.By increasing the single dose of GTV,increasing the dose rate of it.The accelerated repopulation of tumor cells can be effectively overcome.Do not increase the dose of organs at risk,so improve the safety of treatment theoretically.Because it does not need to shrink the irradiation field to formulate a radiotherapy plan again,it can achieve a better homogeneity of the dose distribution in the target area,and at the same time reduce the length of hospitalization of the patient,thereby reducing the treatment cost.This prospective study was performed on patients with locally advanced esophageal squamous cell carcinoma.Each patient was given SIB-IMRT.By counting the completion of each patient’s treatment and the target area’s dosimetric parameters,observing the short-term efficacy,acute side effects,long-term effects and health economic indicators,assess the feasibility and safety of this treatment mode and provide a reliable reference for clinical treatment.Material and MethodAccording to the inclusion and exclusion criteria,72 patients with locally advanced esophageal squamous cell carcinoma who participated in our clinical trial(ChiCTR1900021001)from April 2018 to December 2019 were enrolled.All people were treated with SIB-IMRT.The doses were 59.92Gy/28F,2.14Gy/F of GTVnx/GTVnd and 50.4Gy/28F,1.8Gy/F of CTV/PTV,and irradiation was performed 5 days a week,once a day.Individualized chemotherapy regimens are used based on the patient’s physical condition.Dose parameters are calculated according to the dose volume histogram(DVH),and the characteristics of dose distribution are evaluated.Record short-term efficacy,acute toxic and side effects and economic indicators.Survival was followed up for 1 year.SPSS 25.0 software was used for statistical analysis.Continuous variables were summarized using descriptive statistical methods such as mean,median,and standard deviation,and categorical variables were summarized using frequency and their percentages.The correlation between the ordered and continuous variables are analyzed using the Kendall’s tau-b correlation coefficient method.Kaplan-Meier drawing survival curve method and COX regression method were used to analyze the influencing factors of curative effect.Statistical significance exists when P<0.05.Result1.One patient discontinued radiotherapy due to esophageal-mediastinal fistula.The remaining 71 completed radiation therapy as planned,and the radiotherapy completion rate was 98.6%.2.Dose statistics show that the average dose of GTV was 62.3±1.6Gy and the average dose of CTV was 51.3± 1.8Gy.The former increased by 21%compared with the latter.The radiation dose of lungs,heart,and spinal cord were within the limits.3.The short-term effect evaluation showed that 9 cases(12.7%)with complete response(CR),55 cases(77.5%)with partial response(PR),7 cases(9.9%)with stable disease(SD),no disease progression(PD),and effective rate(CR+PR)of 90.1%.4.The acute adverse reactions were mainly radiation pneumonia,radiation pharyngitis.esophagitis,radiation skin damage.radiation upper gastrointestinal damage and hematological toxicity.The first three were all grade two or less.Three patients(4.2%)had grade 3 acute radiation upper gastrointestinal injury.Twelve(16.9%)patients had grade Ⅲ myelosuppression and 2(2.8%)patients had Ⅳdegree myelosuppression.No acute cardiac or spinal cord injury.Correlation analysis between lung dosimetry parameters and the grade of radiation pneumonitis showed that the V20 and V30 of right lung were positively correlation with radiation pneumonitis(both P values were 0.019).5.Follow-up as of January 2020.Patients who had completed treatment before January 2019 were included in the follow-up(a total of 31 cases).Five patients(16.1%)had local progress,7 patients(22.6%)had distant metastasis,1 patient(3.2%)had both local progress and distant metastasis,and the remaining 18 patients(58.1%)were in stable condition.10 patients died and 21 patients survived.The local control rate,PFS rate and OS rate of 1-year was 80.6%,58.1%and 67.7%,respectively.Multivariate Cox regression analysis showed that higher mean dose of GTV and concurrent chemotherapy could reduce the risk of local tumor recurrence(P=0.026 and 0.028).6.Health economics statistics show that the average length of hospitalization of 71 patients was 55 ± 9 days,and the average hospitalization cost was 65,520 ±18,700 yuan.ConclusionSIB-IMRT can effectively increase the GTV dose for patients with locally advanced esophageal squamous cell carcinoma,with well homogeneity and conformity of target area.Short-term efficacy of this treatment was high.And it could be well tolerated for toxic and side effects and could obtain better survival benefits.Besides,it can reduce the risk of local recurrence tumor by increasing the GTV dose or concurrent chemotherapy.It has certain health economics value. |
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