A new surgical marker has improved targeting for breast cancer radiotherapy.
The many refinements in breast conservation ther- apy have resulted in greatly improved treat- ment. But surgeons and radiation oncol-ogists still face challenges in working together
to more accurately target radiotherapy that
is both clinically effective and achieves the
best cosmetic result.
The problem isn’t the radiotherapy
delivery methods themselves. Technologies such as 3D conformal, intensity
radiotherapy, brachytherapy, volumetric
modulated arc therapy, and multi-beam
approaches are admirably precise. But, until
this time, they have not been widely used in
the treatment of breast cancer.
The reason these methods are not more commonly used for breast cancer patients is the lack of a
reliable way to delineate the target area with a high degree of accuracy. Without that, treatment planners can’t always take advantage of the
technology at their command.
But now, this too appears to be changing for the better. Recently,
a new approach has emerged that marks the target area with greater,
reproducible accuracy and it appears to have other advantages for
post-operative radiotherapy as well. This approach uses a new medical
device that is placed by a surgeon when tissue is removed. The surgically implantable, spiral incorporates six permanent titanium clips that are
"suspended" in a fixed three-dimensional arrangement that can clearly
The marker is sutured to the lumpectomy cavity at the time of tumor
excision after removal of the tumor and surrounding margins is complete. The spiral is made of bioabsorbable material that is reabsorbed by
the patient’s body slowly over time. The titanium clips remain, because
they can provide specific, stable, long-lasting landmarks so the site of
the excised tumor can be clearly visualized over time.
To understand how best to use this three-dimensional tissue marker
(called BioZorb, made by Focal Therapeutics), it helps to review the
current state of how physicians identify the lumpectomy site within the
breast after tissue is removed. The surgical area can be identified by
using small surgical clips individually placed during surgery, or phy-
sicians can rely on external anatomic landmarks and/or tissue changes
surrounding the seroma cavity as seen on a CT scan. Each of these
current methods can be somewhat problematic. For instance, the clips
can migrate during the post-surgical healing process or the seroma
cavity may be gone by the time radiation treatments are
delivered, thus leaving the surgical site unidentifiable
within the breast.
This means there’s often guesswork in
defining the area needing therapy. To compen-
sate, treatment planners must err on the side
of caution to prevent a cancer recurrence.
In other words, they typically can target a
much larger area than necessary. The result:
adjacent healthy tissues can be unintention-
ally damaged by exposure to radiation when
treating the cancer site. This may negatively
affect the cosmetic outcome and, more impor-
tantly, can also lead to complications such as
harm to nearby structures like the heart or lungs.
In my surgical practice, I have implanted this 3D
marker in more than 60 patients. Its performance has
been impressive and virtually trouble-free. I have not seen
any device-related complications – nor have I needed to remove any
devices because of an infection or other issue. Also, patient acceptance
of the new marker is very high. The cosmetic results have been excellent
because the 3D marker allows treatment planners to target the radiation
much more tightly than other markers. This minimizes exposure to
healthy tissue and bodily structures. The device is placed using stan-
dard surgical techniques.
For the marker to be more widely used, of course, its usefulness
has to be confirmed by other surgeons and physicians as well. Several
centers have presented promising results, and four of my colleagues and
I have presented our results at the 2013 annual meeting of the American
Society of Breast Surgeons.
We reported on our initial series of patients, which involved 15 women who were implanted with the device. Most of them received standard
whole breast irradiation (WBI) and were given a boost to the tumor
bed. In five patients we were able to compare boost volumes with and
without the 3D marker. When the 3D marker was used, we typically ( 4
of 5) saw a 30 percent volume reduction in the boost volume, compared
to traditional methods (mean reduction 59 percent).
Another intriguing finding concerned the seroma. The tissue changes around the seroma cavity are often used as a marker for radiotherapy.
In our patients, however, six of the 15 (40%) had no seroma or fluid
outside the area outlined by the tissue marker. The 3D marker was able
to identify the site in some of those cases -- meaning it was useful in
instances where traditional methods could not be employed.
Michael J. Cross, M.D., F.A.C.S., Breast Treatment Associates