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.