| Part Ⅰ:Clinical efficacy and prognosis of adjuvant radiotheray after breast conservative surgery for stage I-II breast cancerObjective:To analyze the clinical efficacy and prognostic factors of radiotherapy with or without chemotherapy after breast conserving surgeryfor stage Ⅰ-Ⅱ breast cancer.Methods:Atotal of 1376 patients with stage Ⅰ and Ⅱ(T1-2N0-1M0/T3N0M0)breast cancer were retrospectively reviewed.All patients were treated with radiotherapy with or without chemotherapy following breast conservative surgery.Of them,446 patients received radiotherapy alone,whereas 930 patients received radiotherapy and chemotherapy.The disease-free survival(DFS)and overall survival(OS)rates were calculated using the Kaplan-Meier method,and differences were compared using the log-rank test.Results:The median follow-up time was 55 months.The 5-year DFS and OS rates for all patients were 94.6%and 98.6%.The 10-year OS rate was 88.0%for radiotherapy alone group and 93.8%for sequential radiotherapy and chemotherapy group(P=0.400),and the corresponding DFS rate was 87.2%and 82.2%(P=0.047),respectively.The mutivatiate analysis revealed that the age(P=0.016),T(P=0.006),N(P=0.004)and time to radiotherapy after surgery(P=0.048)were independent prognostic factors for DFS in patients.Subgroup analysis showed that patients in radiotherapy alone group are more likely to be elder age,better histological grade,less Microvasculari Invasion(MVI),high ER or PR positive ratio,high HER-2 negative ratio,early T stage and N stage(P<0.001).Multivariate analysis showed that N stage(P=0.044,HR=4.708,CI 1.041-21.306)and ER(P=0.026,HR=0.274,95%CI 0.088-0.859)were independent prognostic factors for DFS in radiotherapy alone group.Conclusion:The treatment outcome of radiotherapy after breast conservative surgery for stage Ⅰ-Ⅱ breast cancer is favorable.The prognostic factors for disease-free survival included age,T,N,vascular tumor thrombus,and the time from breast-conserving surgery to radiotherapy.The clinical features of radiotherapy group were better than those of radiotherapy and chemotherapy group.The N stage and ER level were the prognostic factors for disease-free survival in the radiotherapy group.Part II:The time effect of radiation therapy after breast conservative surgery in patients with stage I-II breast cancer.Objective:To analyze the effect of delayed radiotherapy after breast conserving surgery for stage I-II breast cancer,and investigate the relationship between the start time of postoperative radiotherapy using recursive partitioning andamalgamation analysis.Methods:From 1999 to 2013,a total of 930 patients with T1-2N0-1M0 or T3N0M0 breast cancer were retrospectively reviewed.All patients were treated with sequential radiotherapy and chemotherapy following breast conserving surgery.Of them,517(55.6%)patients received radiotherapy first and 413(44.4%)patients received chemotherapy first.The disease-free survival(DFS)and overall survival(OS)rates were calculated using the Kaplan-Meier method,and differences were compared using the log-rank test.Results:The 5-year DFS and OS rates for all patients were 93.9%and 98.6%.The 5-year OS rate was 98.9%for radiotherapy first group and 98.2%for chemotherapy first group(P=0.071).The corresponding DFS rate was 93.0%and 95.6.8%(P=0.238),respectively.The mutivatiate analysis revealed that the age(P=0.029),T stage(P=0.001),N stage(P=0.050)and time to chemotherapy initiation after surgery(P=0.030)were independent prognostic factors for DFS in patients.Recursive partitioning and amalgamation(RPA)found three groups with radiotherapy time after surgery:<5.4 weeks(W),5.4-11 W,≥11 W.There was significant difference in DFS between three groups(P=0.022),the group of 5.4-11 W was the worst.The start time of postoperative radiotherapy less then 5.4 W had better DFS in radiotherapyfirst group(P=0.017),and the radiotherapy initiation time less then 23 W had better DFS in chemotherapy first group(P=0.048).Conclusion:The treatment outcome of radiotherapy and chemotherapy after breast conserving therapy for stage I-II breast cancer was favorable.The risk of disease relapse increased with delay of chemotherapy delivery.Radiation therapy should be given within 23 weeks in patients who received radiotherapy followed by chemotherapy after breast conservative surgery,and within 5.4 weeks in patients who received chemotherapy followed by radiotherapy.Part Ⅲ:Sequence of radiotherapy and chemotherapy after breast conservative surgery:a retrospective cohort study.Objective:To analyze the effect of sequence of adjuvant radiotherapy and chemotherapy after breast conserving surgery,and investigate the prognostic role of molecular subtypes on different treatment sequence in patients with breast cancer.Methods:From 1999 to 2013,a total of 1154 patients with T1-2N0-3M0 breast cancer were retrospectively reviewed.All patients were treated with sequential radiotherapy and chemotherapy after breast conserving surgery.Of them,603 patients received radiotherapy first and 551 patients received chemotherapy first.The disease-free survival(DFS)and overall survival(OS)rates were calculated using the Kaplan-Meier method,and differences were compared using the log-rank test.Results:The 5-year DFS and OS rates for all patients were 93.0%and 97.8%.The 5-year OS rate was 98.6%for radiotherapy first group and 95.6%for chemotherapy first group(P=0.191),and the corresponding DFS rate was 92.7%and 83.5%(P=0.430),respectively.The 5-year OS rate of Luminal A subtype was 99.6%and 97.8%between two groups(P=0.789),and for Luminal B subtype,it was 94.2%and 96%(P=0.680),respectively.The 5-year OS rate for patients with triple negative breast cancer was 100%and 95.8%between two groups,respectively(P=0.019).The 5-year DFS rate for patients with HER-2 positive breast cancer was 80%and 100%between two groups(P=0.045).Conclusion:OS and DFS rates were not significantly differences between radiotherapy followed by chemotherapy and chemotherapy followed by radiotherapy after breast conserving surgery.Patients with HER-2 positive breast cancer showed a better DFS in chemotherapy first group,whereas patients with triple negative breast cancer had better OS in radiotherapy first group.Further research is warranted to investigate the benefit of different molecular subtypes in different sequences of radiotherapy and chemotherapy after breast conservative surgery. |
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