Radiation Therapy and Breast Conservative Surgery: A Concise Review
Correspondence Address :
Dr. Sanjeev Chandra Joshi
Advance Medical and Dental Institute, University Sains Malaysia, Lot 1-8, PSN Seksyen 4/1, Bander Putra Bertam, 13200, Kepala Batas, Pinang, Malaysia, Tel: 04 – 5791990, Fax: 04 – 5742099, Email: scjoshi71@hotmail.com, scjoshi@amdi.usm.edu.my
Radiotherapy has an established role in reducing the local relapses in breast cancer patients. The objective of this review was to investigate whether radiotherapy or its omission after breast surgery has measurable consequences on local tumor recurrence and patient survival. The late excess of cardiac deaths has also been published in various reports but important advances in the delivery of radiotherapy have overcome this problem to the extent that, excess cardiac deaths do not appear to be occurring in more recent trials. In this article some recent data, suggesting that radiotherapy following mastectomy and/or breast conserving surgery has a beneficial effect on survival is reviewed. Omission of radiotherapy is associated with a large increase in risk of ipsilateral breast tumor recurrence and with a small increase in the risk of patient’s mortality.
Radiotherapy, Breast cancer, Recurrence, Mortality
The role of radiation therapy in the treatment of early breast cancer is changing. Breast-conserving therapy has been used in an increasing proportion of patients with early-stage disease beginning in the 1980s. At the same time as breast-conserving surgery (BCS) therapy was reducing the number of mastectomies, the use of post mastectomy irradiation was decreasing due to the perception that it did not improve survival. The role of radiotherapy to the breast for treatment of early-stage breast cancer has recently been challenged because routine radiotherapy after conservative surgery in early-stage breast cancer may be complicated by not only treatment-related morbidity but also limited radiotherapy resources. Therefore, assessment of the role of radiotherapy for patients diagnosed with early-stage breast cancer is needed. This article is written to re-evaluate the role of radiotherapy in early-stage breast cancer by performing an independent pooled analysis of published trials in the literature.
Review of literature
Role of radiotherapy in the treatment of breast cancer has a long and controversial history. (1) Till date there is enough evidence available, this demonstrates that radiotherapy reduces the local relapse. However the reduction in relapse rates did not translate to a reduction in mortality. Many explanations have been suggested for this disparity including detrimental effect of radiotherapy or immune system. (2) The first evaluation of mortality concerns in an individual patient data overview (3) showed that radiotherapy has little effect on mortality in first ten years of follow up, but was potentially detrimental in longer term. Reports for Rutqvist etal(4) and Cuzik J etal (5) clearly demonstrated that there was a late excess of cardiac deaths that was masking a potential reduction in deaths from breast cancers. Further confirmation of these findings was provided by many larger subsequent trials(6). The consensus of these published data does not mean to dismiss radiotherapy as a treatment modality for breast cancer, but to make clear that changes in its administration were needed if its benefit in terms of late breast cancer deaths was not to be nullified by increased mortality. Radiation oncologists have accepted this challenge, and important modifications to the fields used and individual patient planning have greatly reduced the cardiac doses. Excess cardiac deaths do not appear to be occurring in more recent trials, and breast cancer deaths are indeed reduced. (7), (8)
Some recent data suggests that radiotherapy following mastectomy and / or breast-conserving surgery has a beneficial effect on survival.(9) Three randomized clinical trials of post-mastectomy radiotherapy (7), (10), (11) from Canada and Denmark , have shown a 9 – 10% improvement in overall survival at 10 years for patients that received radiotherapy compared with those who did not receive radiotherapy. These results contrast with those of a patient-based meta-analysis of randomized clinical trials (12), in which radiotherapy was shown to be associated with a reduced risk of dying of breast cancer; however, this reduced risk was offset by increased mortality from vascular causes. There are several possible explanations for this apparent discrepancy. Many of the trials included in the patient-based meta-analysis, were initiated a long time ago, and these trials were often small and involved radiotherapy techniques and fractionation schedules that resulted in higher doses to heart than are obtained with modern radiotherapy techniques. In a reanalysis of data from these trials, a substantial reduction was found in the risk of mortality associated with radiotherapy of 12.4% (p< .001) when only recent trials were included(13). In addition patients treated in Canadian and Danish trials received adjuvant chemotherapy and or / tamoxifen in conjunction with radiotherapy. Hence if the burden of distant micrometastasis can be reduced by systemic therapy, then radiotherapy given to the locoregional sites might prevent secondary dissemination, thus being potentially curative. This hypoythesis is supported by results of meta-analysis of randomized clinical trials of adjuvant radiotherapy(14), in which patients also received systemic therapy. In these trials, adjuvant radiotherapy statistically significantly reduced the risk of mortality (odds ratio = 0.83, 95% confidence interval [Cl] =0.74 to 0.94; p=.04). These results have led to the general acceptance that radiotherapy given after breast conservative surgery among patients
In summary, trials of breast irradiation following BCS continue to support the evidence that irradiation substantially reduces not only the risk of local recurrence but also improves the survival. This also prevents the need of mastectomy and improves the cosmesis among the breast cancer patients. The various acute and long term morbidity negative effects described in literature appear to be limited. This review supports the role of radiotherapy among the patients with breast cancer after breast conserving surgery (BCS)
- Emerging Sources Citation Index (Web of Science, thomsonreuters)
- Index Copernicus ICV 2017: 134.54
- Academic Search Complete Database
- Directory of Open Access Journals (DOAJ)
- Embase
- EBSCOhost
- Google Scholar
- HINARI Access to Research in Health Programme
- Indian Science Abstracts (ISA)
- Journal seek Database
- Popline (reproductive health literature)
- www.omnimedicalsearch.com