CAN THE COSMETIC OUTCOME BE IMPROVED IN THE POSTMASTECTOMY RECONSTRUCTED BREAST REQUIRING RADIATION?
With little fear of contradiction, one would assume that most patients requiring post-mastectomy radiation (PMRT) would undergo radiation prior to undergoing definitive reconstruction. No doubt, some surgeons would insert a tissue expander in attempt to save their patient an additional surgical procedure. It should be noted however that this approach would result in a better cosmetic outcome are living in a data-free zone.
The primary issue, however, is not the surgical procedure but the radiation, which by all accounts has an adverse effect on breast reconstruction whether by an implant or autologous tissue. After discussions with many radiation oncologists in various parts of the country, I have concluded that most, if not all believe that the clinical treatment volume (CTV) should include the pectoralis muscles and chest wall. This is despite the fact that an overwhelming majority of local recurrences occur in the subcutaneous tissues and residual breast tissue. We have all misjudged situations and performed reconstruction only to find that that an unexpected adverse pathology, requires radiation. I have in some of those instances tried to convince the radiation oncologist to treat only the skin and subcutaneous tissue over the reconstructed breast, but to no avail.
Unfortunately, there is little outcome data dealing with CTV in patients undergoing PMRT with completed breast reconstruction. Fortunately, this article, which is a consensus of ESTRO (European Society for Radiation and Oncology) and ACROP (This Advisory Committee on Radiation Oncology Practice) suggests that a different approach may be appropriate. The authors point out that PMRT techniques in women having had reconstruction are usually field based as opposed to volume based so that in most instances the CTV includes the reconstructed breast. This inevitably leads to an increase in implant loss and poorer cosmetic results in both the autologous and implant reconstructed breast. This consensus group focused on limiting the CTV to clinically relevant areas and thereby reducing the risk of reconstruction-related complications.
The image seen here outlines a typical radiation field in a patient with a reconstructed breast. This CTV clearly involves treating the chest wall and implant. The panel would reserve this extensive field for patients with more advanced local disease.
Compared to the field-based CTV above, this treatment field includes only the skin, subcutaneous tissues and the axillary tail, while sparing the reconstructed breast and chest wall.
Though we lack solid data when considering outcomes, it would seem that in well-selected patients, using more limited CTVs should yield results comparable to our current approach of more extensive radiation fields.