Quantifying the Effects of Combination Trastuzumab and Radiation Therapy in Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer.

The in vitro results showed the additive effect of combination trastuzumab and radiotherapy. The in vivo results showed the potential to achieve similar efficacy of radiotherapy with a reduced dose when combined with trastuzumab. If trastuzumab and low-dose radiotherapy induce greater tumor kill than a higher dose of radiotherapy, combination therapy can achieve a similar reduction in tumor burden.