The Safe Use of 125I-Seeds as a Surgical Localization Technique for Breast Cancer Patients During Breastfeeding and Close Contact With an Infant

Eva Heeling; Jeroen B van de Kamer; Annemarie Bruining; Jip M E Pluim; Marie-Jeanne T F D Vrancken Peeters; Christianne A R Lok; Iris M C van der Ploeg

doi:10.1016/j.clbc.2025.05.008

The Safe Use of ¹²⁵I-Seeds as a Surgical Localization Technique for Breast Cancer Patients During Breastfeeding and Close Contact With an Infant

Clin Breast Cancer. 2025 May 14:S1526-8209(25)00132-6. doi: 10.1016/j.clbc.2025.05.008. Online ahead of print.

Authors

Eva Heeling¹, Jeroen B van de Kamer², Annemarie Bruining³, Jip M E Pluim⁴, Marie-Jeanne T F D Vrancken Peeters⁵, Christianne A R Lok⁶, Iris M C van der Ploeg¹

Affiliations

¹ Department of Surgical Oncology, Netherlands Cancer Institute Antoni van Leeuwenhoek, Amsterdam, The Netherlands.
² Department of Radiation Oncology, Netherlands Cancer Institute Antoni van Leeuwenhoek, Amsterdam, The Netherlands.
³ Department of Radiology, Netherlands Cancer Institute Antoni van Leeuwenhoek, Amsterdam, The Netherlands.
⁴ Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Medical Physics, Jeroen Bosch Ziekenhuis, 's-Hertogenbosch, The Netherlands.
⁵ Department of Surgical Oncology, Netherlands Cancer Institute Antoni van Leeuwenhoek, Amsterdam, The Netherlands; Department of Surgery, Amsterdam University Medical Center, Amsterdam, The Netherlands. Electronic address: m.vrancken@nki.nl.
⁶ Department of Gynaecologic Oncology, Netherlands Cancer Institute Antoni van Leeuwenhoek, Amsterdam, The Netherlands.

PMID: 40506302
DOI: 10.1016/j.clbc.2025.05.008

Abstract

Purpose: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

Keywords: Breast conserving surgery; Infant < 1 yr; Iodine-125; Radiation exposure; Safety.