What is radiotherapy?
It is the therapeutic use of ionising radiation (high energy electromagnetic waves) for the treatment of cancer. For breast cancer treatment, it is most commonly delivered by means of external beam radiation and involves the chest wall as well as the lymph nodes of the supraclavicular, infraclavicular and axilla (armpit).
Why is radiotherapy used in breast reconstruction?
Radiation therapy has an important role in breast conserving surgery and in preventing local recurrence.
What effect does radiation have on the tissues?
It produces tissue toxicity by several mechanisms. The first is by direct damage to the DNA within cells. The second is by the production of free radicals (derived from oxygen within the tissues), which causes damage to surrounding cellular molecules.
What happens to the skin?
There are multiple effects upon the skin, which happens at different stages:
- Early changes resemble a burn.
- Long-term changes, which appear over 6-12 months, include skin pigmentation, dryness, thickening and subcutaneous fat atrophy. These phenomena result in the skin losing its healing potential and becoming tough and inelastic.
An irradiated area is a very unpleasant environment to operate in and breast reconstruction within an irradiated field is difficult with poorer results. The risk of healing problems and infection is increased, because the tissue is less pliable, less forgiving, more unpredictable, and predisposed to breakdown.
Timing?
The optimal timing for breast reconstruction in the context of radiation is a difficult question to answer. As a rough guide, for a delayed reconstruction, it is best to wait one month for every week of radiation administered, before commencing breast reconstructive surgery. In an immediate reconstruction, the reconstruction of a patient’s breast is started at the time of mastectomy and decisions are made based on the information available at the time.
What types of reconstruction are done?
Autogenous reconstructions, like latissimus dorsi flaps, transverse rectus abdominus muscle flaps and free tissue transfers, are considered safer options in the context of irradiation since they import healthy, resilient tissue into the affected area.
Alloplastic reconstruction (implant-based reconstruction) is more difficult in an irradiated breast.
Alloplastic reconstruction in the previously irradiated breast
- Tissue expansion is an excellent surgical method to recruit tissue. Unfortunately the effects of radiation result in a less favourable experience in most cases of tissue expansion.
- The process of ‘stretching’ the tissues after radiation therapy (to accommodate an implant) is very difficult and sometimes impossible.
- The experience is associated with more discomfort, the recruitment of less tissue (than would be possible in a radiation free environment), rib cage contour deformities and a greater risk of infection.
- The subsequent breasts are harder, lack projection and have a greater risk of asymmetry. There is also a greater risk of extrusion of an implant.
- The need for surgical capsulotomies (to release a tight area around an implant) is more common.
- It may be required to do capsular contracture releases (for tightening and constriction of the scar tissue around an implant), along with the importation of additional non-irradiated tissue for coverage.
- Autogenous tissue reconstructions tend to behave better in the context of irradiation. The transfer of healthy fat into irradiated areas has shown great promise, by improving the quality of the tissue, improving healing and leading to better outcomes.
When can an implant be used in an irradiated area?
Alloplastic reconstructions can be undertaken if:
- There is little or no visible evidence of radiation damage to the skin.
- The amount of expansion needed is small.
- The patient understands the inherent risks.
In summary
Breast irradiation does not eliminate the possibility of breast reconstruction, it changes the options and the manner in which it is performed. Tissue expansion and implants have a limited role due to the high risk of complications. Cosmetic outcomes can be less than ideal.
A select group of patients can undergo the process if they have suitable soft tissue and understand the difficulties of what needs to be done. Such patients can have very high satisfaction rates.
Protocols and understanding continue to improve, as well as the emergence of new techniques like fat transfer, which will greatly improve outcomes in the future.
MEET THE EXPERT
