Radiation Dose Intensity Study in Breast Cancer in Young Women: a Randomized Phase III Trial of Additional Dose to the Tumor Bed
Title of the study:
Radiation dose intensity study in breast cancer in young women: a randomized phase III trial
of additional dose to the tumor bed.
Background and aim of the study:
Several studies showed that breast conserving therapy (BCT) yields similar survival rates as
mastectomy. BCT consists of lumpectomy followed by whole breast radiotherapy (WBRT). Three
studies showed that an additional dose to the tumor bed, after 50 Gy WBRT, reduces the local
recurrence rate (LRR). The largest of these 3 studies was a recent EORTC trial, which also
showed that young age was an independent risk factor for LR after BCT.
In patients < 51 years of age, the LR rate was reduced with 50% after a 66 Gy dose to the
tumor bed, compared to 50 Gy (5-year LRR 12% vs 5.9%, p < 0.02). However, the LRR in young
women was still quite high (> 1% per year). Therefore the first aim of the study is to
investigate whether an additional boost dose to the tumorbed (26 Gy) reduces the LRR
further. Therefore, we will compare the effect of a low boost dose (16 Gy) with the effect
of a high boost dose (26 Gy) on the LRR, but also on the cosmetic outcome.
The second, very important aim of this study is to investigate whether we can find genetic
or protein profiles that correlate with LRR, lymph node metastases, distant metastases,
survival, radiosensitivity, and age. For this purpose we will obtain frozen tumor material
and blood samples of as many patients as possible.
Population, study design, intervention:
Patients younger than 51 years of age, with stage T1-2N01-2aM0 breast cancer, and where the
tumor can be locally excised with acceptable cosmetic result, will be randomized between a
16 Gy boost dose to the tumorbed and a 26 Gy boost dose to the tumor bed, after 50 Gy WBRT.
Patients will be stratified based on age, tumor size, lymph node metastases, estrogen
receptor status, interstitial or external boost irradiation, and institution. In principle
frozen tumor samples and blood samples will be stored of each patient.
Endpoints and statistics:
The primary endpoint is LRR are 10 years. The secondary endpoint is cosmetic result, which
will be quantified using digitized color photographs. In addition, patients will be asked to
give their opinion about the cosmetic result using standardized questionnaires.
To find an increase in the local control rate of 88% to 93% at 10 year, with a power of 80%
and a significance level of 5%, 580 patients will be included in each treatment arm.
An extremely important aspect of this trial is to obtain fresh tumor material and blood
samples. These will be used to determine genetic and protein profiles aimed at finding
subgroups based on these profiles, which may take more or less advantage of the additional
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment
Local control at 10 yr
at every follow up visit (< 2 months after last radiation treatment and thereafter yearly
Liesbeth Boersma, MD
MAASTRO Clinic, Heerlen
Netherlands: The Central Committee on Research Involving Human Subjects (CCMO)