Clinical investigation: breast
Radiotherapy of the chest wall following mastectomy for early-stage breast cancer: impact on local recurrence and overall survival

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Abstract

Introduction: Recent studies have renewed an old controversy about the efficacy of adjuvant radiotherapy following mastectomy for breast cancer. Radiotherapy is usually recommended for advanced disease, but whether or not to use it in pT1–T2 pN0 situations is still being debated. This study was designed to clarify whether or not routine radiotherapy of the chest wall following mastectomy reduces the risk of local recurrence and if it influences the overall survival rate.

Methods: Retrospective analysis of patients treated with mastectomy for pT1–T2 pN0 tumors and no systemic treatment. Patients treated with radiotherapy of the chest wall following mastectomy (Group A) are compared with those treated with mastectomy alone (Group B).

Results: A total of 918 patients underwent mastectomy. Patients who received adjuvant radiotherapy after mastectomy (n = 114) had a significantly lower risk for local recurrence. Ten years after the primary diagnosis, 98.1% of the patients with radiotherapy were disease free compared to 86.4% of the patients without radiotherapy. The average time interval from primary diagnosis until local recurrence was 8.9 years in Group A and 2.8 years in Group B. The Cox regression analysis including radiotherapy, tumor size and tumor grading found the highest risk for local recurrence for patients without radiotherapy (p < 0.0004). In terms of overall survival however, the Kaplan–Meier analysis showed no difference between the two groups (p = 0.8787) and the Cox regression analysis failed to show any impact on overall survival.

Conclusion: With observation spanning over 35 years, this study shows that adjuvant radiotherapy of the chest wall following mastectomy reduces the risk for local recurrence in node-negative patients with pT1–T2 tumors but has no impact on the overall survival rate.

Introduction

Halsted’s demand for radical mastectomy as treatment of choice for breast cancer dates back to the 1880s and was based on the understanding of breast cancer as a locoregional disease. This view was questioned by a series of studies between 1950 and 1970 (1). These studies established the advantages of limited local therapy and finally led the way to breast conserving surgery (2).

A similar development can be observed concerning the role of postoperative radiotherapy of the chest wall following mastectomy. Until the late 1970s, postmastectomy radiotherapy was routinely administered. In the face of increased risk of local recurrence in patients who received no adjuvant radiotherapy, it was assumed that optimal tumor control could be achieved by routine postoperative radiotherapy. The expanding knowledge about early systemic dissemination of tumor cells and its predominant role in overall prognosis of the disease changed this policy in the early 1980s (3). It has now been widely accepted for many years that postoperative radiotherapy of the chest wall after mastectomy should be restricted to cases with advanced stages of disease and/or with extensive lymphangiosis carcinomatosa and positive margins of resection 4, 5.

More recent studies have shown that the increased risk for local recurrence, however, which is associated with a more selective use of chest wall irradiation, might also lead to a reduced overall survival. (6)

We studied patients who underwent mastectomy for pT1–pT2 pN0 pM0 stage breast cancer (tumor no more than 5 cm in greatest dimension [T2], no regional lymph node metastasis [N0], no distant metastasis [M0]) 7, 8, with observation periods of up to 28 years, to find out whether routine radiotherapy following mastectomy reduced the risk of local recurrence and whether it influenced the overall survival rate.

Section snippets

Methods and materials

Longitudinal data were available for 918 patients who were treated with modified radical mastectomy for primary breast cancer between 1963 and 1998. Patients who underwent radical or extended radical mastectomy or any other means of primary surgical treatment were excluded from the study. Study sites were the Departments of Gynecology of the University Hospitals in Berlin-Charlottenburg (1963–1987), and in Munich (I. Frauenklinik, since 1987). Data were contemporaneously gathered in the

Results

Patients’ characteristics (summarized in Table 1 ) are comparable in both groups. The systematic surgical exploration of the axilla was performed more extensively in the group after 1979. In this group an average of 11 lymph nodes (standard deviation, 5.4) were removed compared to an average of 6 single embedded lymph nodes (standard deviation, 2.9) in the group before 1979. The average tumor size observed in both groups was identical at 17 mm. In Group B (treated after 1979) histopathologic

Development of adjuvant radiotherapy after mastectomy

Decreasing extensiveness of local surgery has marked the history of treatment strategies for primary, operable breast cancer over the past 100 years. At the same time, an increasing variety of systemic therapeutic options, such as chemotherapy and endocrine therapy, has become available.

Beginning in the 1970s, however, data were published showing that the increased incidence of local recurrence is not necessarily associated with a less favorable overall survival rate 13, 14. In 1986, the

Conclusion

Adjuvant radiotherapy of the chest wall following mastectomy reduces the risk of local recurrence for systemically untreated early-stage breast cancer. This decrease has no impact on the overall survival rate.

Acknowledgements

The authors are sincerely grateful to David and Sally Gray for their editorial support.

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    Supported by a grant from the Friedrich-Baur Stiftung, Muenchen, Germany.

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