Let me begin by saying – this review article is worth your time to read. The Medscape article examines the most recent literature on breast reconstruction in patients receiving post-mastectomy radiation therapy (PMRT) and presents it in a fashion that is meant to assist in making the best treatment decisions.
They introduce the subject by reviewing the evidence that supports the use of post-mastectomy radiation therapy.
PMRT can improve survival and local-regional control in selected patients with invasive breast cancer treated with mastectomy and systemic therapy. Local-regional and survival benefits of PMRT for patients with lymph node-positive disease. Survival advantage associated with PMRT was evident both for patients with 1-3 positive lymph nodes and those with 4 or more positive lymph nodes. Accordingly, the use of PMRT for patients with stage II breast cancer is increasing
Breast reconstruction following mastectomy is also an important aspect of care for many patients with breast cancer. It is important that reconstruction does not compromise the goal of breast cancer treatment: to maximize the probability of cure and permit patients to return to a normal quality of life.
So what is the optimal timing and technique of breast reconstruction in patients requiring PMRT? It is controversial. Like most medical treatment, “one size doesn’t fit all.” This article does a nice job of making some sense of it.
Implant-Based Breast Reconstruction in Patients Receiving PMRT
Studies evaluating the outcomes of 2-stage breast reconstruction (placement of a tissue expander followed by placement of a permanent breast implant after PMRT) consistently reveal high rates of acute and chronic complications and poor aesthetic outcomes.
Capsular contracture that results from PMRT can distort the appearance of the breast and cause potentially significant chronic chest wall pain and tightness.
Many surgeons attribute the poor outcomes with implant-based breast reconstruction to older, less precise techniques of radiation delivery. However, even with modern radiation delivery techniques, complication rates with implant-based reconstruction are high.
In addition, fibrotic changes around breast implants associated with PMRT can continue to evolve years after treatment; early results of new techniques often underestimate the true incidence of complications.
Current Role of Reconstruction With a Latissimus Dorsi Flap
Evans and colleagues found that the addition of the tissue flap -- either a transverse rectus abdominis myocutaneous (TRAM) flap or a latissimus dorsi myocutaneous flap -- did not appear to protect against capsular contracture, a common complication of PMRT.
In 2007, Spear and colleagues concluded that in patients with unsatisfactory outcomes after 2-stage implant-based reconstruction as a result of the adverse effects of radiation, breast contour can be improved by adding a latissimus dorsi flap, generally to the inferior pole of the breast.
Effect of Immediate Implant-Based Breast Reconstruction on Radiation Treatment Field Design
Not only can PMRT adversely affect the aesthetic outcome of immediate implant-based breast reconstruction, but there is increasing evidence that such reconstructions may interfere with the delivery of PMRT.
Chest wall treatment in patients who have undergone reconstruction must be accomplished by using traditional, 2-beam tangential fields alone rather than the modern, 3-beam technique. As mentioned, this can deliver potentially harmful doses of radiation to the heart or lung.
This is something that truly needs to be considered in woman who need or may need post-mastectomy radiation therapy. The article has some nice visuals that help explain the physics for those interested.
Autologous Tissue Breast Reconstruction in Patients Receiving PMRT
Although the consensus in the literature is that autologous tissue is preferable to breast implants within an irradiated operative field, autologous tissue reconstructions may also be adversely affected by PMRT.
However, autologous tissue reconstructions can interfere with the radiation field design and can also lead to adverse changes in the aesthetic reconstruction outcome.
This issue of the reconstruction, no matter which technique, is a requiring theme. This needs to be considered. Delayed reconstruction may be the best option in patients who are known at the time of mastectomy to require PMRT.
Effect of Immediate Autologous Tissue Breast Reconstruction on Radiation Treatment Field Design
Immediate reconstruction substantially compromised treatment of the internal mammary nodes and made it less possible to use a modern, 3-beam technique with a separate medial electron beam to treat this region. In patients with right-sided reconstructions, the chest wall and internal mammary chains were treated with deeper tangential beams (traditional, 2-beam tangential beam technique) at the expense of irradiation of more lung parenchyma. In patients with left-sided reconstructions (accounting for 67% of the compromised treatment plans), the heart and lung were spared at the expense of suboptimal coverage of the chest wall and internal mammary nodes. Sixty-five percent of patients with compromised internal mammary node coverage also had compromised coverage of the chest wall and suboptimal sparing of lung and epicardial heart structures (including the left anterior descending branch). Thus, even if the internal mammary nodes had not been treated, these patients' plans would not have been optimal.
Delayed-Immediate Breast Reconstruction
It is best to do delayed breast reconstruction in women who will need radiation therapy. This is not always known prior to the mastectomy as it may hinge on the receptor studies. However, by delaying the reconstruction, the benefits of immediate reconstruction are lost. These benefits include the ability to preserve of the breast skin envelope and the natural contour of the inframammary crease which give the opportunity for the best aesthetic outcome.
One option that decreases the adverse effects of PMRT through more targeted therapy and helps ensure optimal radiation delivery after immediate breast reconstruction is delayed-immediate reconstruction.
This approach involves placing a tissue expander at the time of mastectomy to preserve the initial shape and thickness of the breast skin flaps and the dimensions of the breast skin envelope until the final pathology results are available. In patients found not to require PMRT, preservation of the breast skin envelope enables the plastic surgeon to achieve optimal aesthetic outcomes. The outcomes are found to be similar to those obtainable with immediate breast reconstruction.
In patients who require PMRT, the tissue expander can be deflated before the start of PMRT to create a flat chest wall surface and permit modern, 3-beam radiation delivery. The expander can be reinflated after PMRT to permit "skin-preserving" delayed reconstruction.
Integrating Radiation Therapy and Breast Reconstruction: Which Comes First?; Medscape Article, January 30, 2009; Thomas A. Buchholz, MD, FACR; Steven J. Kronowitz, MD, FACS
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