Recent controversy on breast brachytherapy is sparked by the fact that the number of
women receiving the treatment is on the rise even before the American
Randomized Prospective Trial has been completed and published. Meanwhile the
guidelines by several American societies focus on the cautious selection of
eligible candidate to receive brachytherapy as an alternative to Whole Breast
Radiation (WBI). Dr. Catheryn Yashar M.D. Oncologist and Brachytherapy
Specialist of UC San Diego Moores Cancer Center, sheds light on the concerns
impacting brachytherapy offered to women.
Q. One of the advantages of brachytherapy
is the limited timeframe in comparison to WBI, what are the other benefits of
A. With partial breast
radiation therapy or breast brachytherapy, the treatment depends on the method
employed, but from one centimeter to 2 centimeter of the tissue that is at risk
to harbor cancer cells is irradiated. So once a woman has a lumpectomy and the
tumor is removed, brachytherapy or accelerated partial breast radiation really
only treats one to 2 centimeters of tissue surrounding where the tumor used to
be. On the other hand whole breast radiation therapy, which takes 3-6 weeks,
treats the entire breast. Hence it's not just the shorter time span but also
less tissue is treated with partial breast radiation therapy than with whole
breast radiation therapy.
Q. How is the eligibility of a person to
receive brachytherapy determined?
A. Among the numerous
guidelines published in the United States, the most stringent is from ASTRO
(American Society of Therapeutic Radiation Oncology). It recommends into an
unsuitable category women that should be treated with partial breast only on an
open trial. The suitable category is women over 60 with invasive tumours that
are 2 centimeters or less and are ER (Estrogen Receptor)
positive. There are also the cautionary group of tumors between 2 and 3
centimeters, women between 50 and 60 years old, ductal carcinoma in situ and
some other risk factors. So when a woman is interested in partial breast
therapy, I would go over in detail the pathology of the breast cancer and then
discuss what we know about partial breast radiation therapy and what we don't
know. We thoroughly discuss the guidelines so that we make the decision on the
appropriate treatment together.
Q. To what extent does a doctor's
intervention help a woman with breast cancer decide what treatment
(brachytherapy or WBI) is in her best interest?
Brachytherapy takes shorter treatment time, and less normal tissue is treated.
We go over the unknown details such as the trials that are yet to be published
and the risks of both whole breast therapy and partial breast therapy. We
discuss that we have to wait for the results of those trials before we are
certain that partial breast irradiation is equivalent to the standard of care,
which is full breast radiation therapy. I basically walk the women through that
data to help them make the choice that is appropriate for them. Many women like
partial breast radiation therapy and are happy with it, although in many women
it is not considered the standard of care. It is appropriate only for the
earliest, lowest risk cancers. But for women in whom it is appropriate and who
choose to do it, it is a very convenient method of treatment, where we can
conform the dose nicely to area of the breast at most risk for recurrence and
limit radiation to the other tissues such as lung, heart, and ribs that don't
harbor cancer cells but are difficult to avoid in whole breast radiation
Q. Wouldn't women be at a disadvantage
the longer it takes for the trials to be published?
True, but whole breast radiation is available and is an excellent treatment
choice. The Hungarians have actually published a randomised prospective trial
and then there is another randomised prospective called the TARGIT trial in
which case the radiation would be offered in the operating room. The Italians
have also recently published a trial on partial breast radiation therapy, so
there are trials that are published that suggest that it may be an alternative.
But in those trials women tend to be older and at the lowest risk for
recurrence and so once again concerning younger women or higher risk breast
cancer we have to wait for trials to demonstrate that it's equivalent. Some women
are not comfortable with the lack of data and are very accepting of whole
breast radiation therapy. No one is trying to get rid of WBI; we are just
hoping that partial breast radiation therapy will be, in appropriate women, a
more convenient and less toxic alternative.
Wonderful advances have been observed in brachytherapy
since 2006 that have enabled the physician to shape the dose much better than
we could with the original balloon brachytherapy. The type of brachytherapy
used in the Hungarian trial, interstitial brachytherapy, involved the placement
of multiple catheters through the breast tissue. This method allows the most
precise dose shaping to the person's anatomy but the skill and experience level
it requires is much greater and not all physicians are comfortable with that
method. The new multicatheter devices are far easier to place and plan so in
the appropriate woman a more attractive option.