The Effect Of Radiotherapy On Survival In Patients With Breast Carcinoma In Situ:A SEER Based Study

ObjectiveDuctal carcinoma in situ(DCIS)is a non-invasive malignant tumor of the breast.In 2020,it accounted for approximately 17%of the total number of new breast cancers in the United States that year.Breast-conserving surgery is a common surgical method for the treatment of DCIS,but there is still some controversy about whether radiotherapy is required after breast-conserving surgery.This study tried to analyze the influence of various factors on the clinical choice of radiotherapy and patient prognosis and tried to answer whether postoperative radiotherapy can benefit patients with DCIS and whether postoperative chemotherapy can benefit patients in all subgroups.It also tries to suggest a predictive model for the risk of recurrence and death to help doctors and patients make judgments about whether to choose postoperative radiotherapy.MethodThis study selected the records of a total of 50,580 patients whose first primary tumor was breast carcinoma in situ from the SEER data from 1998 to 2015 and used the patient ID to match the information of their second primary tumor on the same side of the breast as Signs of postoperative recurrence.Afterwards,a multivariate Cox risk model was used to determine the effects of covariates on disease-specific survival(DSS),disease-free survival(DFS)and overall survival(OS).Finally established a normogram predictive model and a predictive program.ResultPostoperative radiotherapy for patients undergoing breast-conserving surgery for OS(HR 0.69,95%CI 0.64-0.74,P<0.001),DSS(HR 0.53,95%CI 0.44-0.64,P<0.001)and DFS(HR 0.5,95%CI 0.46-0.55 P<0.001)are all independent protective factors.In the subgroup analysis,postoperative radiotherapy can benefit patients in almost all subgroups.However,in the subgroups of elderly patients(age greater than 80 years)and small tumors(tumor less than or equal to 2mm),there was no statistical difference in DSS between postoperative radiotherapy or not(P=0.783 and P=0.563).In the subgroups of small tumors,there was also no statistical difference in OS between postoperative radiotherapy or not(P=0.606).In group multivariate analysis,diagnosis age,tumor size,nuclear grade and estrogen receptor status are independent predictors of DSS and DFS.Conclusion1.In clinical practice,patients who are younger,poorer nuclear grade,larger tumors,ER negative,and received partial mastectomy rather than subcutaneous mastectomy are more likely to receive radiotherapy,which is the risk of DCIS that is generally believed in the clinic The factors are the same.2.In the overall population,postoperative radiotherapy can benefit DCIS patients in OS,DSS and DFS.3.Patients with advanced age(81 years and older)or small tumors(<0.2mm)may not be able to benefit from DSS after postoperative radiotherapy.And patients with small tumors(<0.2mm)may not be able to benefit from OS after postoperative radiotherapy ether.4.Constructed a predictive model to predict the DSS and DFS corresponding to a certain patient receiving or not receiving radiotherapy after breast-conserving surgery to assist clinical decision-making.