The Addition Of Radiotherapy Following To Conserving Surgery For Ductal Carcinoma In Situ: A Meta Analysis

Aim: To summarise the results of randomized controlled trials（RCT） testing the radiotherapy following breast conservingsurgery(CSR) in women with ductal carcinoma in situ (DCIS); toinvestigate the real impact of radiotherapy on ipsilateral breast tumorrecurrence（IBTR, including DCIS or invasive）, contralateral breasttumor recurrence(CBTR), regional recurrence, distant metastasesdisease-free survival and mortality rate; to determine whether there aresubsets of women with DCIS who could not benefit from CSR；tocompare the effect of radiotherapy to women with DCIS in differentfollowing time.Methods: A meta-analysis of randomized controlled trials wasperformed comparing CSR for DCIS of breast in women to observation(CSO). The Pubmed（1966-2012.2）、Cochrane Central Register ofControlled Trials(CENTRAL), Clinical trails, Sloane Project, Trails andResearch, CBM（1978-2012.2）, CNKI(1994-2012.2）,VIP(1989-2012.2)were searched. Hand search recent issues of relevant journals, textbooks, annals and relevant conference abstracts. The selection of studies forinclusion and trials data abstraction was carried out independently by tworeviewers. The quality of included studies was evaluated by using thescales proposed by Jadad. Meta-analysis was performed by Revman5.0software. The risk of bias was tested by SAS9.1.3software.Results: The reviewers identified four large RCTs, involving3925patients. Meta-analysis yielded a summary incidence of IBTR，the ratewas26.6%for CSO, and13.2%for CSR. The mortality rate and breasttumor-relative death rate were9.7%and6.1%in the CSO arm, however10.0%and6.6%in another arm. Analysis showed a statisticallysignificant reduction from the addition of radiotherapy on IBTR by51%[OR=0.41,95%CI(0.35,0.49)P<0.00001] compared with non-radiotherapy.The reduction on DCIS-IBTR and invasive-IBTR（I-IBTR）were54%and46%，respectively. The significant reduction of IBTR in the first5yearsand even to10years or10years later of follow-up wassimilar(OR=0.40,0.42,0.39). The disease-free survival was significantlyincreased by5.8%as for the addition of radiotherapy[OR=0.65,95%CI(0.54,0.79),P<0.0001]. Patients who had low orintermediate grade couldn’t benefit from the radiation therapy，althoughthere were no differences on other subgroups analyzed (age, tumor size,tumor was resected completely or not and comedonecrosis present orabsent).Patients who were more than50years, had comedonecrosis,whose tumor were resected completely got individually more benefitfrom the radiation therapy when compared with the other groups. Therewas no evidence for a differential effect of radiotherapy on CBTR, regional recurrence, distant metastases, mortality rate and breasttumor-relative death rate.Conclusion: The pooled data showed that CSR for DCIS of breastin women resulted in a significant reduction on IBTR，which alsoincreased the disease-free survival, though there was no benefit forCBTR，regional recurrence, distant metastases，mortality and breasttumor-relative death rate compared with CSO. The significant reductionof IBTR was not only represented in the first5years of follow-up butalso continued to10years later. Patients who had low or intermediategrade couldn’t benefit from the radiation therapy. All the other subgroupsanalyzed benefited from the irradiation with the trend that patients whowere more than50years, had comedonecrosis, whose tumor wereresected completely benefited more from the addition of radiationtherapy.