[Histonet] Re: breast tissue and radioactive seeds

[Bob Richmond]

Kaye (where?) inquires:

We are going to be starting a new procedure here called "Conversion to
Radioactive Seed Localized Breast Surgery" and I have been asked to come to
this meeting.  As I have been strictly in Dermatology for the past few
years I am not familiar with this process. I have dealt with the prostate
radioactive seeds before but not sure if this will involve the Histology
lab in the form of surgical tissue or not. I would like to be as informed
as possible before the meeting which is next week, so I came to the source
I value the most. Can anyone share any information with me?
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To which Phil Gilbert (also where?, but he has a British accent anyway):

We've recently started using this procedure, so a (very) brief synopsis as
follows:

Rather than a wire localisation of a breast tumour (using ultrasound) where
a surgeon follows the wire to excise the tumour, a tiny radioactive seed is
used instead. The seed is injected by syringe into the tumour, where it is
"held" by the tissue (rather than a wire which can become dislodged by
movement of the patient). The surgeon then uses a fine-tuned radiation
meter to locate the seed (and thus the tumour) for excision.

>From theatre, the breast excision specimen is x-rayed by our Radiology Dept
to confirm that tumour does not appear to be at the resection margins (if
it does, then a re-excision is done). Critically, because the seeds can be
placed totally within the tumour, very few immediate shave re-excisions are
required - this is the great advantage.

The histology lab receives the specimen, where we need to be very careful
not to fracture/cut the seed. We use our own x-ray cabinet to show
whereabouts in the specimen the seed is lying. Once the specimen is sliced,
the seed is retrieved and the specimen trimmed as normal.

Here in the UK, the main concern over this technique is that no source of
radiation can be lost (down a trimming bench sink, onto the floor etc.). We
therefore have a complex chain of custody record which confirms the
presence of the seed by radiation monitor at all areas of the hospital.
*********************************
I Googled an excellent clinical article on radioactive seed localized
breast surgery, apparently widely used at more than one Mayo Clinic.

James W. Jakub MD et al. (Mayo Clinic, Rochester MN). Current status of
radioactive seed for localization of non palpable breast lesions. The
American Journal of Surgery, Vol 199, No 4, April 2010.
The article in full is accessible at
http://health.usf.edu/nocms/medicine/breasthealth/PDFDocuments/Radioactive%20Seed%20Localization.pdf

The review article and the comments suggest equipment (specimen x-ray
machine, gamma counter) which the ordinary surgical pathology lab doesn't
have access to. The "seed" contains a charge of iodine 125 (gamma emitter,
half-life 60 days) which can be accidentally cut into. You may assume
you'll get your first specimen without warning, just like you got your
first sentinel node specimen.

You need to have a pathologist staying on top of this and providing
feedback, but he probably won't have the authority to do anything, and they
won't send him for training.

Bob Richmond
Samurai Pathologist
Maryville TN