Top Line: Accelerated partial breast irradiation (APBI) delivered with intensity modulated radiotherapy (IMRT) to 30 Gy in 5 fractions achieved excellent cosmesis on a prospective randomized trial.
The Study: So what are the cosmetic outcomes when delivering APBI with a robotic stereotactic radiation unit? Here is a South Korean prospective observational cohort looking at roughly 100 women receiving APBI using CyberKnife as compared to another 100 women receiving standard whole breast radiation with rigorous objective and subjective cosmesis endpoints. CyberKnife uses unique non-coplanar beam arrangements in comparison to LINAC-based IMRT. However, dose distribution was homogeneous and the treatment planning goals were very similar to standard IMRT goals when planning APBI. At 6 months, APBI resulted in significantly lower rates of patient-reported breast hardness (8 v 20%), dryness (7 v 18%), and skin reaction (10 v 24%). At 12 months, physician-reported dermatitis was also significantly lower after APBI at 1 v 7%. A final interesting endpoint was breast fibrosis in each quadrant as measured with a tissue compliance meter. Perhaps as expected, there was no difference in measured fibrosis in the involved quadrant after APBI versus whole breast irradiation. However, measured fibrosis was significantly lower in uninvolved quadrants at 12 months after ABPI.
TBL: “Toxicity and cosmetic results [after APBI] seem to be strongly influenced by the radiotherapy technique and radiotherapy fractionation regimen.” | Byun, Int J Radiat Oncol Biol Phys 2023
The Study: So what are the cosmetic outcomes when delivering APBI with a robotic stereotactic radiation unit? Here is a South Korean prospective observational cohort looking at roughly 100 women receiving APBI using CyberKnife as compared to another 100 women receiving standard whole breast radiation with rigorous objective and subjective cosmesis endpoints. CyberKnife uses unique non-coplanar beam arrangements in comparison to LINAC-based IMRT. However, dose distribution was homogeneous and the treatment planning goals were very similar to standard IMRT goals when planning APBI. At 6 months, APBI resulted in significantly lower rates of patient-reported breast hardness (8 v 20%), dryness (7 v 18%), and skin reaction (10 v 24%). At 12 months, physician-reported dermatitis was also significantly lower after APBI at 1 v 7%. A final interesting endpoint was breast fibrosis in each quadrant as measured with a tissue compliance meter. Perhaps as expected, there was no difference in measured fibrosis in the involved quadrant after APBI versus whole breast irradiation. However, measured fibrosis was significantly lower in uninvolved quadrants at 12 months after ABPI.
TBL: “Toxicity and cosmetic results [after APBI] seem to be strongly influenced by the radiotherapy technique and radiotherapy fractionation regimen.” | Byun, Int J Radiat Oncol Biol Phys 2023