HypoG-01 UNICANCER trial

Dr Elisa Agostinetto, medical oncologist at Institut Jules Bordet in Brussels, discussed with Dr Sofia Rivera, a radiation oncologist at Institut Gustave Roussy, France the outcomes of the HypoG-01 phase 3 UNICANCER trial that she presented during the presidential session. 

The trial compared normal fractionated radiotherapy (NF RT) with moderately hypofractionated radiotherapy (HF RT) for breast cancer patients receiving nodal irradiation. NF RT involved a five-week regimen of 50 Gy in 25 fractions, while HF RT used a three-week regimen of 40 Gy in 15 fractions. The trial aimed to assess the non-inferiority of HF RT, particularly in terms of arm lymphoedema, which was the primary endpoint, as there were concerns that higher doses per fraction could increase toxicity, especially in larger volumes involving the heart, lungs, and axillary structures.

The trial included 1,265 patients across 29 French centres. The results showed that HF RT was non-inferior to NF RT in terms of lymphoedema risk and did not raise concerns about safety or other key outcomes such as DFS or OS. These findings support the use of HF RT for loco-regional RT in early breast cancer, potentially reducing treatment time without increasing toxicity.

Although HF RT is already standard in some countries like the UK, in France, NF RT had remained the norm. The trial’s results are expected to change this practice in France, despite economic and reimbursement challenges. Dr. Rivera noted that while previous trials focused on smaller volumes like breast-only radiation, this study was the first phase 3 trial to assess nodal irradiation with modern techniques.

Looking ahead, both doctors discussed future trials aiming to reduce treatment time further, such as the UK’s Fast Forward trial, which investigates a one-week, five-fraction regimen. Dr. Rivera emphasised the need for careful, high-quality research to avoid long-term toxicities in patients with high cure rates. She mentioned that several trials are already underway to evaluate ultra-HF approaches in nodal irradiation, with results expected in the next five to ten years.