A Phase II Study of the Use of Deep Inspiration Breath Hold and Prone Irradiation to Decrease Cardiac Radiation Exposure

This study aims to discover more about radiation techniques for people treated for left-sided
breast cancer that minimizes exposure to the heart, as noted by mean heart dose. Both prone
(lying face down) radiation and DIBH (Deep Inspiration Breath Hold) are more labor-intensive
and usually require longer treatment times for patients than traditional supine (lying face
up) free-breathing radiation treatments. Thus, identifying people that benefit most from
these techniques can better utilize resources. This study compares supine and prone
positioning, with or without DIBH, to further assess which positioning technique will achieve
the lowest cardiac radiation doses.

A pilot portion of this trial will determine the presence or absence of echo abnormalities
and EKG findings predictive of Heart Failure with Preserved Ejection Fraction in breast
cancer patients prior to, soon after, and in follow-up after radiation therapy for breast
cancer. Ejection fractions are expected to be normal in study patients but there may be
evidence of risk markers after radiation.

This study will measure mitochondrial function in leukocytes (peripheral blood mononuclear
cells) from patients prior to and after undergoing radiation therapy, and a gradual decline
in mitochondrial energy biomarkers over time after radiation therapy is expected.

Inclusion Criteria:

- Patients must have a pathologically proven diagnosis of left-sided invasive breast
cancer or ductal carcinoma in situ receiving breast/chestwall irradiation +/- regional
nodal irradiation, or a right-sided invasive ductal cancer status post-mastectomy or
lumpectomy who will be receiving breast/chest wall and nodal irradiation.

- Patients must have undergone breast conserving surgery (i.e. lumpectomy, partial
mastectomy) or mastectomy prior to enrollment.

- Patients must be 18 years of age or older.

- Study entry must be prior to CT simulation.

- Per MCW Department of Radiation Oncology Standard of Care, women of childbearing
potential must be non-pregnant and non-lactating and willing to use medically
acceptable forms of contraception during radiation therapy. Patients under age 50 with
a uterus and ovaries must have a negative serum pregnancy test within one week of
planned CT simulation per Radiation Oncology Departmental guidelines prior to CT
simulation.

- Patients must provide study specific informed consent prior to study entry.

- Patients must be able to hold their breath long enough to undergo CT simulation in
DIBH (ten to fifteen seconds). The patient should also affirm they can lie in the
prone position. This will be determined by the treating radiation oncologist, as per
current standard of care.

Exclusion Criteria:

- Patients who are unable to hold their breath long enough to undergo CT simulation in
DIBH. While this may affect patients with COPD and/or other respiratory conditions,
the presence of these comorbidities alone will not exclude patients from enrollment so
long as they can maintain breath hold long enough to perform DIBH.