Radiation and Implants

Introduction

Post-mastectomy radiation therapy (PMRT) has clearly defined indications for locally advanced breast cancer, but recent studies point to increasing benefits in loco-regional control using PMRT in less advanced cases – there is thus a trend to increasing indications for PMRT. The deleterious effects of PMRT on implant based reconstructions are well documented as are consistently reported increased complication rates and decreased patient satisfaction rates. Exact rates differ widely between inhomogeneous groups making direct comparisons difficult. Nevertheless, with increasing PMRT indications combined with specific patient factors and desires, it behooves the well-rounded plastic surgeon to have a plan when dealing with these particularly challenging reconstructions. This debate has never been more relevant.

Advanced strategies

  1. The Fast-track Method

Described by Peter Cordeiro in 2004, this method involves placement of expanders at the time of mastectomy, with filling during adjuvant chemotherapy, with implant exchange 4 weeks after completion and PMRT after a further 4 weeks. His extensive data suggest that satisfactory results are achievable and that possibly the negative effects PMRT are lessened after the completion of the implant reconstruction. In centres where neo-adjuvant chemotherapy is preferred, this method may not be applicable. There are of course numerous other protocols where the timing and sequencing vary. Interestingly, multiple studies have shown that overall complication rates between the various protocols are no different.

  1. The Immediate-Delayed Method

This method suggested by Kronowitz and Robb involves limited access skin sparing mastectomy with expander placement and complete filling on the table. Total muscle coverage is not achievable. If PMRT is required, the expander is deflated completely to allow 3 beam PMRT coverage and subsequently re-inflated after completion of the PMRT. Definitive implant exchange is accompanied by latissimus flap. Interestingly, most of the patients described by Kronowitz subsequently had a tissue based reconstruction.

  1. Lipofilling

Recent work by Diego Ribuffo using lipofilling on irradiated expanders has shown very promising results. His protocol includes using low and medium height expanders under total muscle cover, with rapid expansion (100cc per week) over a 2 month period to full volume. Standard PMRT was administered without deflation and lipofilling was done 6 weeks after completion of the PMRT. Implant exchange and low anterior capsulectomy was performed after 3 months. Significant decreases in overall complication rate, capsular contracture rates and improvements in patient satisfaction were noted. This method is likely to gain acceptance if these results are generally reproducible.

Personal recommendation

My personal protocol is to perform a delayed (6-12 months) two stage alloplastic reconstruction, preserving the radiated skin, but adding additional skin as well as total sub-muscular cover by utilizing an non-irradiated latissimus flap over the expander. I usually perform at least one session of lipofilling and do this after the definitive implant. This differs from reports by both Evans and Spear who utilize this flap over the definitive prosthesis with less satisfactory results. Although it remains an uncommon option in my practice, I have had very pleasing results using this method.

Conclusion

Implant-based reconstructions in the setting of PMRT are particularly challenging – multiple studies have shown major complications occur in more than 40% of cases and that reconstructive failure occurs in more than 15% of cases. While an overall success rate of 70% may seem good, in reality, patient satisfaction rates are usually significantly lower than this. Because of this, a tissue based reconstruction is generally preferred, but there are patients in whom no other options may be available (or desired).