Wednesday, September 2, 2009

Radiation Therapy and Breast Reconstruction—an Article Review

Updated 3/2017-- all links (except to my own posts) removed as many no longer active. and it was easier than checking each one. 

Postmastectomy radiation therapy is important for many women.  It can improve survival and locoregional control in patients with invasive breast cancer.  When considering the optimal time and technique of breast reconstruction in patients who require postmastectomy radiation therapy, it can often be a difficult decision.  This topic of timing and best technique remain controversial.   There is no general agreement among plastic surgeons.
This article attempted to review the most recent literature on breast reconstruction in patients receiving postmastectomy radiation therapy.  They did a nice job.
To find articles for review, we performed a search of the MEDLINE database for studies of radiation therapy and breast reconstruction. We then read the reference lists of the identified articles to find additional articles for review. Studies were included if most patients were treated after 1985 and the mean follow-up period was more than 1 year. Forty-nine articles were reviewed.
Just from the headings in the article you can get a sense of the complexities of this topic:
  • Indications for Postmastectomy Radiation Therapy: Consensus and Controversies
  • Design of Postmastectomy Radiation Therapy: Consensus, Controversies, and the Potential for Lower Dose Regimens
  • Implant-Based Breast Reconstruction in Patients Receiving Postmastectomy Radiation Therapy
  • Outcomes of Implant-Based Reconstruction with Modern Radiation Delivery Techniques
  • Impact of Performing the Tissue Expander-Permanent Implant Exchange before Rather than after Radiation Therapy
  • Current Role of Reconstruction with a Latissimus Dorsi Flap Plus a Breast Implant in Breast Cancer Patients Who Receive Postmastectomy Radiation Therapy
  • Immediate Implant-Based Breast Reconstruction Can Compromise the Design of the Radiation Treatment Fields
  • Autologous Tissue Breast Reconstruction in Patients Receiving Postmastectomy Radiation Therapy
  • Timing of Flap Transfer in Relation to Postmastectomy Radiation Therapy
  • Immediate Autologous Tissue Breast Reconstruction Compromises the Design of the Radiation Treatment Fields
  • Delayed-Immediate Breast Reconstruction

Looking at the how “immediate implant-based breast reconstruction can compromise the design of the radiation treatment fields” the authors note the growing evidence that
Not only can postmastectomy radiation therapy adversely affect the aesthetic outcome of immediate implant-based breast reconstruction, there is also increasing evidence that such reconstructions can interfere with the delivery of postmastectomy radiation therapy.
This can be from the slope of  the reconstructed breast vs the flat un-reconstructed chest changing the geometry of the medial and lateral radiation fields.  This can lead to under-dosing of the chest wall, especially centrally underneath the breast prosthesis and near the internal mammary nodes. 
On the good news (for reconstruction) side, studies have found no significant radiation scatter from the metallic port within the tissue expander used for breast reconstruction.
Kronowitz and colleagues highlight a 2005 study from M. D. Anderson Cancer Center which noted that immediate breast reconstructions may limit treatment planning for postmastectomy radiation therapy.  Bold highlighting is mine.
They retrospectively reviewed the records of 152 patients treated with postmastectomy radiation therapy, 17 of whom underwent immediate breast reconstruction and had expanders, flaps, and/or implants in place at the time of postmastectomy radiation therapy. The authors evaluated the impact of various reconstructive techniques on the ability to treat the breadth of the chest wall, treat the internal mammary nodes within the first three interspaces, avoid the lung, and avoid the heart. They found that completely deflated expanders resulted in no compromise; a partially deflated expander prevented treatment of the internal mammary nodes; and fully inflated expanders moderately or severely compromised treatment of the internal mammary nodes and chest wall.

Timing of reconstruction can be difficult as you don’t always know who is going to require postmastectomy radiation therapy.
…. recommendations regarding postmastectomy radiation therapy are often based on pathologic analysis of the mastectomy specimen, the need for postmastectomy radiation therapy is not always known at the time of mastectomy.
So perhaps “delayed-immediate breast reconstruction” might become the standard of care.  Here are their key points regarding this heading:
Until we can reliably predict the need for postmastectomy radiation therapy, decrease its adverse effects through more targeted therapy, and ensure optimal radiation delivery after immediate breast reconstruction, delayed-immediate reconstruction may be the best option with which to maintain the balance between optimal aesthetic outcomes and effective radiation delivery.
In this approach, a tissue expander is placed 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 results of pathologic analysis are available. 
In patients found not to require postmastectomy radiation therapy, preservation of the breast skin envelope enables the plastic surgeon to achieve aesthetic outcomes similar to those obtainable with immediate breast reconstruction.
In patients who do require postmastectomy radiation therapy, the tissue expander can be deflated before the start of postmastectomy radiation therapy to create a flat chest wall surface and permit modern, three-beam radiation delivery, and the expander can be reinflated after postmastectomy radiation therapy to permit skin-preserving delayed reconstruction.
Placement of the fully inflated expander allows for more precise positioning of the expander on the chest wall. Placement of an inflated expander also avoids the need for skin expansion and stretching of already thin mastectomy skin flaps, which can adversely affect the safety (expander exposure) and aesthetic outcome (telangiectasia formation) of breast reconstruction.
Expanded breast skin also tends not to tolerate postmastectomy radiation therapy; however, maintenance of the initial thickness of breast flaps after mastectomy, as in delayed-immediate reconstruction, results in better tolerance of the inflammatory effects of postmastectomy radiation therapy because the normal architecture of the dermis is preserved.

Radiation Therapy and Breast Reconstruction: A Critical Review of the Literature; Plastic and Reconstructive Surgery. 124(2):395-408, August 2009; Kronowitz, Steven J.; Robb, Geoffrey L. [doi: 10.1097/PRS.0b013e3181aee987]
Articles Reference within Main Article for delayed-immed reconstruction:
Kronowitz SJ, Robb GL. Breast reconstruction with postmastectomy radiation therapy: Current issues. Plast Reconstr Surg. 2004;114:950-960.
Kronowitz SJ. Immediate versus delayed reconstruction. Clin Plast Surg. 2007;96:39-50.
Kronowitz SJ, Kuerer HM. Advances and surgical decision-making for breast reconstruction. Cancer 2006;107:893-907.
Kronowitz SJ, Hunt KK, Kuerer HM, et al. Delayed-immediate breast reconstruction. Plast Reconstr Surg. 2004;113:1617-1628.

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