The Safe Use of ¹²⁵I-Seeds as a Surgical Localization Technique for Breast Cancer Patients During Breastfeeding and...

Currently, Dutch hospitals advise limiting mother-infant contact to 1 hour per day if an ¹²⁵I-seed is implanted for breast cancer surgery, possibly affecting bonding and the child's cognitive and behavioral development. By quantifying radiation exposure from an ¹²⁵I-seed to the infant through breastfeeding and close contact, we aim to provide evidence-based recommendations for clinical practice.

We modelled the radiation exposure to an infant due to contact with a mother or patient with an ¹²⁵I-seed in situ in the breast, assessing both the ipsilateral and contralateral breast at different time periods (14 days, 90 days, and 180 days). The radiation exposure to the infant was considered safe as long as it remained below the threshold of 1 mSv.

When an ¹²⁵I-seed is surgical removed within 14 days after insertion, daily contact on the contralateral contact is safe (up to 24 hours a day). When ipsilateral contact is included, the maximum duration adjusts to 19 hours per day contralateral combined with 5 hours per day ipsilateral. When the ¹²⁵I-seed remains in situ for a longer period, such as during primary systemic treatment (PST) (e.g., 90 or 180 days), contact is possible with certain limitations.

Contralateral close contact (including breastfeeding) with an infant < 1 year of age is safe in case of breast cancer and an ¹²⁵I-seed in situ in the breast. Short moments of ipsilateral contact are safe, even for a longer period of 180 days.