Analysis Of Prognostic Factors Of Cervical Cancer After Hysterectomy And Dosimetric Study Of Intracaviary Brachytherapy Radiotherapy

Part one Analysis of Prognostic Factors of Cervical Cancer after HysterectomyObjective: The efficacy,adverse reactions and prognostic factors of patients with cervical cancer underwentradical hysterectomy at the oncology department of Affiliated Hospital of Northern Sichuan Medical College were analyzed retrospectively.To explore the prognostic factors of adverse reactions and curative effect of patients with cervical cancer after radical operation.Methods: Data of patients with cervical cancer treated by radical surgery at the oncology department of Affiliated Hospital of North Sichuan Medical College from January 2013 to October 2016 were collected.The efficacy and late adverse reactions of patients were followed up by telephone and outpatient reexamination.The deadline of follow-up was 31 December 2018.According to inclusion and exclusion criteria,143 cases were included in this study.The factors influencing recurrence and overall survival of patients after radical surgery of cervical cancer were analyzed retrospectively.Results: A total of 143 patients were collected,among them,109 patients received post-operative adjuvant radiotherapy and 34 patients did not receive post-operative adjuvant radiotherapy,and the median follow-up time was 38.0（26.0-55.0）months.During the follow-up period,43 patients relapsed and 24 died.Disease-free survival was 90.21%,72.45% and 59.76% in 1,3 and 5 years,and the overall survival was 100.00%,89.23% and 74.17% in 1,3 and 5 years.In patients who received adjuvant radiotherapy after radical surgery,the incidence of late radiation proctitis,cystitis,vaginitis were 12.84%（14/109）,14.68%（16/109）and 46.79%（51/109）respectively.In all of the 143 patients,the incidence of lymphedema of lower limbs was 20.98%（30/143）.In patients who received adjuvant radiotherapy after radical surgery,there was no difference in the incidence of radiation proctitis,cystitis and lymphedema of lower limbs between the external irradiation group and the intracavitary brachytherapy combined with external irradiation group,but the incidence of radiation vaginitis in the latter group was significantly higher than that in the former group（P=0.002）.The incidence of lymphedema of lower limbs in the adjuvant radiotherapy group was significantly higher than that in the surgery alone group（P=0.019 in the external irradiation group and P=0.026 in the intracavitary brachytherapy combined with external irradiation group）.Multivariate analysis of tumor recurrence showed that clinical stage,vaginal margin,lymph node metastasis,lymphovascular space invasion and choice of adjuvant therapy were independent risk factors.The higher the clinical stage,the greater the risk of recurrence,HR = 1.450（1.029～2.044）;the risk of recurrence of positive vaginal margin was higher than that of negative,HR = 3.025（1.072～8.536）;the risk of recurrence of positive lymph node metastasis was higher than that of negative,HR=3.072（1.455～6.484）;the risk of recurrence in patients with positive lymphovascular space invasion was higher than that in patients with negative ones,HR = 2.295（1.084～4.860）;adjvant external irradiation and adjvant intracavitary brachytherapy combined with external irradiation were the protective factors of recurrence,HR was 0.082（0.037～0.180）and 0.056（0.007～0.435）respectively.Multivariate analysis of overall survival showed that clinical stage,vaginal margin,parauterine invasion,lymph node metastasis and lymphovascular space invasion were the independent factors affecting overall survival.The higher the clinical stage,the lower the overall survival,HR = 0.402（0.210～0.768）;the higher the risk of death of positive vaginal margin,HR = 0.188（0.042～0.838）;the higher the risk of death of patients with parametrial invasion,HR = 0.122（0.034～0.436）;the higher the risk of death of patients with lymph node metastasis,HR = 0.125（0.039～0.395）;the risk of death in patients with positive lymphovascular space invasion is higher than that in patients with negativeones,HR = 0.174（0.057～0.536）.Adjuvant radiotherapy within 6 weeks after surgery may bring less recurrence rate and survival benefits.Conclusion: The survival rate and the incidence of late adverse reactions of patients with cervical cancer after radical hysterectomy in our cancer center are almost the same as those reported in the current reports.Further improvement of work will bring more benefits to patients.Clinical stage,vaginal margin,lymph node metastasis and lymphovascular space invasion are independent factors affecting recurrence of tumor and overall survival of patients.Postoperative adjuvant radiotherapy can significantly reduce the recurrence of tumors,the impact on long-term survival needs further observation;patients who begin radiotherapy within 6 weeks after surgery have greater benefits,which need study to confirm.Part two Dosimetric study of different applicaors of intracavitary brachytherapy with cervical cancer after hysterectomyObjective: Comparing the dosimetric differences between single-channel cylinder and ovoids in the three-dimensional intracavitary brachytherapy for cervical cancer after hysterectomy.To initially explore the optimal scheme of postoperative brachytherapy to decrease the adverse effects and to provide reference for the selection of different applicators in clinic work.Methods: Collecting 20 patients with cervical cancer who underwent three-dimensional intracavitary brachytherapy from June to December 2018 at the oncology department of Affiliated Hospital of North Sichuan Medical College.Each patient was treated with single-channel cylinder and ovoids respectively.Based on the actual CT data sets of each patient during radiotherapy,a total of 40 CT data sets were used to delineate the clinical target volume and organs at risk according to the unified target area delineation criteria,and then the brachytherapy plan was conducted.The volume of clinical target volume,D₉₀,D₁₀₀,the volume of bladder and rectum and the D2 cc of bladder and rectum in two kinds of applicators brachytherapy plans were collected.Independent sample t-test was used to compare the doses of clinic target volume and doses of organs at risk of the two applicarors in adjvant three-dimensional intracavitary brachytherapy.Results: There was no significant difference in target volume between single-channel cylinder group and ovoids group（29.56 ±4.51）cm³ and（31.68 ±3.16）cm³,（P=0.095）.D₉₀ and D₁₀₀ of the single-channel cylinder were（611.60±8.70）c Gy,（414.38±47.16）c Gy,D₉₀ and D₁₀₀ of ovoids were（608.19±7.30）c Gy,and（359.54±38.13）c Gy,P=0.18,P=0.003 respectively. D₉₀ of the two groups was approximately about 6 Gy,D₁₀₀ between the two groups had significant difference.The rectal volumes of single-channel applicator group and ovoids applicator group were（53.03±10.70）cm³,（52.37 ±8.87）cm³,P = 0.213,with no significant difference;rectal D2 cc were（375.77 ±62.10）c Gy,（341.57 ±38.43）c Gy,P = 0.043,with significant difference;bladder volumes were（129.31±18.90）cm³,（123.14 ±13.15）cm³,P = 0.239,with no significant difference;bladder D2 cc was（391.13 ±62.94）c Gy,（356.42 ±27.12）c Gy,P=0.032,with significant difference.Conclusion: In the three dimensional intracavitary brachytherapy for cervical cancer who underwent radical surgery,compared with ovoids,single-channel cylinder applicator has better target dose distribution,but higher dose for bladder and rectum.It is necessary to select appropriate source types and reasonable combination according to specific conditions in order to improve the therapeutic gain ratio.