Dermatofibrosarcoma Protuberans:A Retrospective Analysis And Systematic Evaluation Of Radiotherapy Effectiveness

Background and objective: Dermatofibrosarcoma protuberans(DFSP)is a low-grade malignant interstitial tumor that occurs in the dermis and subcutaneous.Its clinical manifestations are non-specific.The diagnosis relies mainly on pathological examination,and the rate of misdiagnosis is high.DFSP is characterized by high recurrence rates and low metastatic rates.The main treatment methods are surgical extened resection,other treatments include radiation therapy and molecular targeted therapy.Firstly,we analyzed the clinical features of primary and non-primary cases and DFSP,fibrosarcomatous DFSP(Fibrosarcomatous Dermatofibrosarcoma protuberans,FS-DFSP).Secondly,we analyzed the factors of tumor recurrence providing clinical diagnosis and treatment ideas,and providing theoretical basis for treatment and prognosis.Finally,we used systematic reviews and meta-analyses to evaluate the efficacy of adjuvant radiotherapy for DFSP,providing a clinical basis for postoperative adjuvant radiotherapy.Methods: The first part of the study included 70 cases of pathologically confirmed DFSP from the First Affiliated Hospital of Zhengzhou University from March 2012 to March 2017.The collected cases included primary cases and non-primary cases.The pathological types included classic DFSP and FS-DFSP.The tumor location,age,sex,and tumor size between DFSP and FS-DFSP,primary and non-primary cases were statistically analyzed.Finally,the tumor recurrence factors were analyzed.For the treatment of DFSP,5 patients received radiation therapy at a dose of 55 Gy-65 Gy.The second part provides a systematic review and meta-analysis of articles published before February 23,2019.This study included all studies of DFSP patients who reported postoperative adjuvant radiotherapy.Data were extracted from these studies,and statistical analysis was performed to compare the recurrence rates of surgery and surgery combined with postoperative radiotherapy and the effectiveness of postoperative radiotherapy in patients with positive margins.Results: 1.7 of the 41 primary patients(2.7 years follow-up)relapsed(17.1%),and 11 of the 29 recurrence patients(37.9%)relapsed(12 years follow-up,P = 0.049).2.12 of 59 patients with DFSP(follow-up 2.6 years)relapsed(20.3%),and 6 of 11 patients(54.6%)with FS-DFSP relapsed(1 year follow-up,P = 0.045).3.There was no significant difference in gender(P = 0.808),tumor location(P = 0.946),age(P = 0.267),and tumor size(P = 0.094)between the primary and non-primary groups.4.There was no significant difference in gender(P = 0.743),tumor location(P = 0.470),age(P = 0.401),and tumor size(P = 0.690)between DFSP and FS-DFSP.5.There was no statistically significant difference in gender(P = 0.584),tumor location(P = 0.820),and age(P = 0.874)in non-primary cases.The difference in tumor size(P = 0.003),case type(P = 0,049),and pathological type(P = 0.045)was statistically significant.6.The recurrence rate of the operation combined with radiotherapy group was 8.0%;the recurrence rate of the surgery alone group was 24.14%.There was a difference in the recurrence rate between the surgery combined with radiotherapy group and the surgery only group(P = 0.014).7.Meta-analysis showed that the recurrence rate of the surgery combined with postoperative adjuvant radiotherapy was lower than that of the surgery alone,and the difference was statistically significant(odds ratio 0.28,P = 0.01).The recurrence rate of positive margin in the surgery alone group was 61.5%.The recurrence rate of the positive margin in the operation combined with postoperative adjuvant radiotherapy was 8.0%.There was a significant difference between the two groups(P = 0.00).Conclusion: 1.The recurrence rate of DFSP non-primary group was significantly higher than that of the primary group.The recurrence rate of FS-DFSP is significantly higher than DFSP.2.There was no significant difference in gender,tumor location,age,and tumor size between the patients in the primary group and the non-primary group.It was same to the DFSP group and the FS-DFSP group.3.Gender,tumor location,and age are not risk factors for recurrence,and tumor size,primary case or not,and pathological type are risk factors for recurrence.4.The recurrence rate of surgery combined with postoperative radiotherapy is lower than that of surgery alone.5.The recurrence rate of patients with DFSP positive margin is higher than that of negative margin.For all postoperative positive margin patients,postoperative adjuvant radiotherapy can reduce the recurrence rate.