Referring Physicians >> Newsletters >> Use of Radioactive Seed to Localize Non-Palpable Breast Cancer
Use of Radioactive Seed to Localize Non-Palpable Breast Cancer
Screening mammography has led to the increased detection of non-palpable breast cancers.6 A mainstay of treatment is often surgical excision with breast conservation. In order to complete the procedure, the surgeon requires a way to identify the cancer in the operating room.
The most traditional device used is a small wire, which can be placed beforehand via mammography or ultrasound. Previously reported limitations include:
Due to these many limitations, the use of a radioactive seed has gained popularity as an alternative tool. Previous studies have demonstrated comparable (and possibly improved) operative times, specimen volumes and weights, reoperation rates, and device complications when compared to wire-guided localization.4,9
What is a radioactive seed?
A radioactive seed is an Iodine (I)-125 fully encapsulated titanium seed measuring 4.5 mm in size. It has a usual assayed activity of ~ 200 µ-Ci. This allows for detection with the use of a handheld gamma probe on the skin.
How is it placed?
The seed is contained within a pre-loaded syringe and is placed under image guidance (mammogram or ultrasound) using an 18-gauge needle. Evaluation with a gamma probe on the skin is then completed in the Radiology Department to ensure placement within the breast. A mammogram is finally performed to assess its location in relation to the lesion.
Are there any risks to using a seed compared to a wire?
Potential risks, though small, include seed migration, transection or loss. The seed cannot be repositioned once inside the breast. If incorrectly placed or if migration occurs, then excision is required, regardless of its location.
How is it excised?
In order to locate the seed, the gamma probe is placed on the skin to identify the I-125 signal. Once localized, an incision is placed directly over the area of concern for precise removal of both the seed and lesion. A specimen radiograph is then completed to confirm removal of the radioactive seed.9
Does using a radioactive seed improve surgery?
Some studies have shown a statistically significant improvement in negative margins as well as a decrease in re-excision rates with the use of a radioactive seed as compared to a wire.2,7,10,11 Specifically with high risk lesions, specimen volumes can be significantly decreased.3
Is it safe?
Yes. The radiation exposure to the patient and provider is minimal.
What are the overall benefits to the patient and provider?
Reported benefits of radioactive seed localization include flexibility in scheduling the procedure, convenience on the day of surgery, operator preference from both the surgeon and radiologist, along with patient comfort with both placement and because of its internal location.7,8,11 Operative times have also been shown to be improved when using a seed.1,8
The UW Health I-125 Radioactive Seed Program has been in existence since November 2014. To refer a patient, contact the UW Health Breast Center for further evaluation to determine if a seed is the correct localization tool for the patient’s breast conservation surgery.
1 Sung et al. Safety and efficacy of radioactive seed localization with I-125 prior to lumpectomy and/or excisional biopsy. European Journal of Radiology. 2013; 82. 1453-1457.
2 Chiu et al. Radioactive seed localization of non-palpable breast lesions in an academic comprehensive cancer program community hospital setting. The American Surgeon. 2014; 80: 675-679.
3 Diego et al. Localizing high risk lesions for excisional breast biopsy: a comparison between radioactive seed localization and wire localization. Annals of Surgical Oncology. 2014; 21: 3268-3272.
4 Barentsz et al. Radioactive seed localization for non-palpable breast cancer. British Journal of Surgery. 2013; 100: 582-588.
5 Murphy et al. Radioactive seed localization compared to wire localization in breast-conserving surgery: Initial 6-Month Experience. Annals of Surgical Oncology. 2013; 20: 4121-4127.
6 McGhan et al. Radioactive seed localization for non-palpable breast lesions: Review of 1,000 consecutive procedures at a single institution. Annals of Surgical Oncology. 2011; 18: 3096-3101.
7 Hughes et al. A multi-site validation trial of radioactive seed localization as an alternative to wire localization. The Breast Journal. 2008; 14: 153-157.
8 Lovrics et al. A multi-centered, randomized, controlled trial comparing radio-guided seed localization to standard wire localization for non-palpable, invasive, and in situ breast carcinomas. Annals of Surgical Oncology. 2011; 18: 3407-3414.
9 Jakub et al. Current status of radioactive seed for localization of non-palpable breast lesions. The American Journal of Surgery. 2010; 199: 522-528.
10 Gray et al. Randomized prospective evaluation of a novel technique for biopsy or lumpectomy of non-palpable breast lesions: radioactive seed versus wire localization. Annals of Surgical Oncology; 8: 711-715.
11 Gray et al. Radioactive seed localization of non-palpable breast lesions is better than wire localization. The American Journal of Surgery; 188: 377-380.