| Objective:The purpose of this study is to analyze the efficacy,prognostic factors and toxicity of interstitial brachytherapy in the treatment of local recurrent cervical cancer with previously irradiation.Methods:Between October 2016 to August 2020,patients who recurrent with previously irradiated and excluding distant metastasis were included and treated with interstitial brachytherapy.The prescription doses was 6-7Gy per fraction,1-2 fractions per week and total fractions ranged 1-7 times.The tumor equivalent doses in 2 fractions(EQD2)was calculated according to the linear quadratic equation(LQ).The α/β value of tumor was assumed to be 10,and the median EQD2 was 40.93Gy(range :9.92Gy-69.42Gy).13 patients were treated combined with external beam radiotherapy(EBRT)using 1.8-2Gy/fraction,and the EBRT dose range was 20Gy-54 Gy.Combined with the EBRT,the median EQD2 of re-irradiation was 56.94Gy(range:9.92-111.92Gy).Combined with the initial treatment doses,the median cumulative EQD2 was 129.46Gy(range : 90.07-160.15Gy).The information about the initial treatment,recurrence,re-irradiation and follow-up were collected.Overall survival rate(OS)、local control rate(LC)and progression-free survival rate(PFS)were calculated by Kaplan-Meier method,univariate analysis was performed by Log-Rank test and multivariate analysis was performed using Cox proportional hazards regression analysis to determine the prognostic factors for re-irradiation with interstitial brachytherapy.Early and late toxicity was also assessed.Results:The follow-up ended to January 31,2021,and 32 patients were included in this study,13 of whom received EBRT combined with interstitial brachytherapy,with a median follow-up time of 27.40 months,and the median survival time was 24.10 months(95%CI:13.871-34.329).In terms of short-term efficacy,18 patients(56.25%)had complete response after interstitial(CR),12 patients(37.50%)had partial response(PR),and 2 patients(6.25%)were stable disease(SD).The total response rate(CR or PR)was 93.75%.In terms of long-term efficacy,1-year OS,LC,PFS were 71.7%、65.6%、56.1%,2-year OS,LC,PFS were 51.1% 、45.4% 、 32.4%,3-year OS,LC,PFS were 37.2% 、 34.6% 、 23.2%,respectively.In univariate analysis,recurrence interval and re-irradiation doses were the prognostic factors about LC(p=0.045 and 0.001)、PFS(p=0.034 and 0.000)and OS(p=0.004 and 0.0030),and initial surgery was the prognostic factors of PFS(p=0.031)and OS(p=0.030).In multivariate analysis,the re-irradiation doses was related to LC(p=0.013,HR=0.209,95%CI= 0.061-0.720)and PFS(p=0.009,HR=0.240,95%CI= 0.083-0.695),and the prognostic factors associated with OS were the recurrence interval(p=0.035,HR=0.273,95%CI= 0.082-0.915)and re-irradiation doses(p=0.030,HR=0.269,95%CI= 0.082-0.880).In terms of toxicity,no transplantation-related death occurred,and 15 patients(46.88%)developed early toxicity,including myelosuppression,acute radiation proctitis,acute radiation cystitis,and intestinal obstruction.Among them,5 patients developed myelosuppression and 1 of them ≥grade 3,acute radiation proctitis and cystitis were observed in 7 and 4patients respectively,and all of them were below grade 3,Grade 3intestinal obstruction was observed in 1 patients.The incidence of ≥grade3 early toxicity was 6.25%.Late toxicity occurred in 13 patients(40.63%),the intestinal late toxicity occurred in 10 patients,5 of them ≥3 grade, including 3 patients with rectovaginal fistula and 2 patients with grade 3radiation proctitis.5 patients showed advanced urinary toxicity,1 of them developed ≥ 3 grade toxicity,which was vesicovaginal fistula.The incidence of ≥3 grade late toxicity was 18.75%.Conclusion:The interstitial brachytherapy has achieved satisfactory efficacy.Recurrence interval ≥12 months and re-irradiation doses ≥50Gy are positive prognostic factors for it.The early and late toxicity are low in incidence and tolerable.Therefore,it is feasible to treat local recurrent cervical cancer with previously irradiation. |
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