Elizabeth Nichols, MD

Invited discussant Elizabeth Nichols, MD, of the University of Maryland, School of Medicine, Baltimore, commented on both the phase II TRIUMPH-T and the phase III MC1635 trials.

“There are multiple techniques in use for accelerated partial breast irradiation. Optimal dose and fractionation are controversial due to concerns about cosmetic outcomes, particularly with external-beam radiotherapy. There are also concerns regarding margins and image guidance,” she explained.

“TRIUMPH-T was a single arm multi-institutional trial that showed a great cosmetic profile and great local tumor control. The TRIUMPH-T trial provided more data to continue to support our comfort with a once-daily treatment for accelerated partial breast irradiation. The optimal total dose and fractions still need to be determined, and ongoing discussions will address margin expansions,” Dr. Nichols said.

Regarding the MC1635 trial, Dr. Nichols commented: “This study confirms a great toxicity profile between the moderate hypofractionation arm and the extreme hypofractionation arms, as well as similar quality of life and toxicities.”

However, Dr. Nichols cited several remaining questions: “Is it safe to treat the nodes? Is it going to be better or worse with certain subtypes of breast cancer? Will it be acceptable to give with or during chemotherapy? What are the potential long-term toxicities regarding cardiac and pulmonary outcomes? Will there be an effect on the reconstructed breast?” 

DISCLOSURE: Dr. Nichols reported no conflicts of interest.