Clinical Investigations
The influence of the boost in breast-conserving therapy on cosmetic outcome in the eortc “boost versus no boost” trial

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Abstract

Purpose: To evaluate the influence of a radiotherapy boost on the cosmetic outcome after 3 years of follow-up in patients treated with breast-conserving therapy (BCT).

Methods and Materials: In EORTC trial 22881/10882, 5569 Stage I and II breast cancer patients were treated with tumorectomy and axillary dissection, followed by tangential irradiation of the breast to a dose of 50 Gy in 5 weeks, at 2 Gy per fraction. Patients having a microscopically complete tumor excision were randomized between no boost and a boost of 16 Gy. The cosmetic outcome was evaluated by a panel, scoring photographs of 731 patients taken soon after surgery and 3 years later, and by digitizer measurements, measuring the displacement of the nipple of 3000 patients postoperatively and of 1141 patients 3 years later.

Results: There was no difference in the cosmetic outcome between the two treatment arms after surgery, before the start of radiotherapy. At 3-year follow-up, both the panel evaluation and the digitizer measurements showed that the boost had a significant adverse effect on the cosmetic result. The panel evaluation at 3 years showed that 86% of patients in the no-boost group had an excellent or good global result, compared to 71% of patients in the boost group (p = 0.0001). The digitizer measurements at 3 years showed a relative breast retraction assessment (pBRA) of 7.6 pBRA in the no-boost group, compared to 8.3 pBRA in the boost group, indicating a worse cosmetic result in the boost group at follow-up (p = 0.04).

Conclusions: These results showed that a boost dose of 16 Gy had a negative, but limited, impact on the cosmetic outcome after 3 years.

Introduction

Over the last decade, breast-conserving therapy (BCT) has been established as the treatment of choice for patients with early-stage breast cancer 1, 2, 3, 4. However, specific details of the surgical, radiotherapeutic, and systemic adjuvant approaches are not generally agreed upon. In this paper we will concentrate on one of the controversial items of radiotherapy technique, namely the effects of giving a boost dose to the tumor bed.

The two major endpoints of BCT are good local control and good cosmetic outcome. The influence of the radiotherapy boost on both endpoints, however, is controversial. Pezner et al. 5, 6 claimed that omitting the local boost in patients with tumor-free specimen margins resulted in local control rates comparable to those of other institutions that routinely used a boost. On the other hand, the Lyon trial (7) showed that the delivery of a 10-Gy boost (given in fractions of 2.5 Gy) to the tumor area significantly reduced the risk of early local recurrence in patients with tumor-free margins from 4.5% to 3.6% at 5 years, compared to treatment of the whole breast with a dose of 50 Gy in 2.5-Gy fractions.

A similar controversy exists concerning the influence of the radiation boost on the cosmetic result after BCT. Some studies have concluded that the boost had no effect on the cosmetic outcome, in terms of the degree of breast retraction or the proportion of patients having an excellent or good cosmetic result, although patients treated with a boost may have had an increased frequency of telangiectasia 5, 7, 8. Others have demonstrated a negative effect of the boost on the global cosmetic result 9, 10, 11, 12. One factor that might determine whether or not the boost can be shown to worsen the cosmetic outcome is the time following radiotherapy at which the cosmetic result is evaluated. It is well known that the cosmetic changes progress over the first years after BCT and that the cosmetic outcome is evaluable only after at least 3 years 13, 14, 15, 16. Two of the above-mentioned studies which found no adverse effect of the boost evaluated cosmetic outcome at a median follow-up of 2 years or less (5, 7).

The European Organization for Research and Treatment of Cancer (EORTC) Phase III trial 22881/10882 for Stage I and II breast cancer was created to unequivocally answer the question of the impact of the radiation boost on local control, survival, and cosmesis. The current analysis focuses on the influence of the boost on the cosmetic outcome.

Section snippets

Trial design and treatment

From May 1989 to June 1996, 5569 early-stage breast cancer patients were entered in the “boost versus no boost” trial. Patients with T1-2 N0-1 M0 invasive breast cancer were eligible. Exclusion criteria were: age over 70 years; carcinoma in situ (CIS) without invasive tumor; residual microcalcifications on mammogram or gross residual disease in the breast after tumorectomy (unless reexcision had been performed); tumor foci in more than one quadrant; a prior history of malignant disease; or an

Patient population

An overview of the distribution of the patient, tumor, and treatment characteristics of the different patient populations is given in Table 1. The p-values in this table relate to the comparison of panel patients to the remainder of the population (“others”) and of digitizer patients to patients without any digitizer measurements available (“others”). The characteristics of the no-boost and the boost patients are reported separately for the panel and digitizer patients. There were no

Discussion

The EORTC trial 22881/10882 was launched to investigate in BCT, the influence of the boost on local control, survival, and cosmesis. In this study we have shown that the boost slightly impairs the cosmetic outcome 3 years after BCT. Because the local recurrence rate is only 3.9% so far for the overall population after a median follow-up of 3.8 years, more follow-up is needed before the influence of the boost on local control and survival can be reliably evaluated. Therefore, the answers to

Acknowledgements

The authors thank all the participating institutions for their cooperation, the panel members Jacques H. Borger, Stefan J. Brenninkmeyer, Marianne Pierart, Joop A. Van Dongen, and Erik Van Limbergen for their great effort in scoring the photographs, Ellen Bartelink for performing all the digitizer measurements, and Abram Recht for reviewing the manuscript. This work was partially supported by a grant from the European Commission (DGXII) within the framework of BIOMED I and by Grants

References (24)

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Trial participants and responsible physicians: Tilburg NL (Poortmans), Utrecht NL (Struikmans), Leuven B (Van den Bogaert), Dijon F (Horiot), Paris F (Fourquet), Amsterdam NL (Borger), Heerlen NL (Jager), Nijmegen NL (Hoogenraad), Cologne D (Müller), Geneva CH (Kurtz), Nottingham GB (Morgan), Montpellier F (Dubois), Namur B (Salamon), Lausanne CH (Mirimanoff), Leiden NL (Leer), Grenoble F (Bolla), Haifa IS (Kuten), La Louviere B (Renaud), Krefeld D (Schulz), Rotterdam NL (Koper), Antwerp B (Van den Weyngaert), Brussels B (Storme), Creteil F (Calitchi), Berlin D (Budach), Düsseldorf D (Roth), Brisbane AUS (Poulsen), Pamplona ES (Dominguez), Vannes F (Monpetit), Tel Aviv IS (Kovner), Barcelona ES (Biete Sola), Madrid ES (Calvo)

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