Does Postmastectomy Radiation Therapy Worsen Outcomes in Immediate Autologous Breast Flap Reconstruction?

Author: Belle Liew, University College London, MBBS Year 3 (iBSc)

Breast cancer is the most pervasive cancer in the United Kingdom, constituting 15% of all new cancer diagnoses¹. Surgical excision of the primary tumour with breast-conserving surgery or skin sparing mastectomy (SSM) is the mainstay of treatment. Breast reconstruction following SSM has become increasingly popular, but the optimal timing of breast reconstruction, either with implants or autologous flaps, is widely debated. Much of this controversy centres on whether a patient may need adjuvant post-mastectomy radiotherapy (PMRT).

Earlier studies have reported increased morbidity with both implant-based and autologous immediate breast reconstruction (IBR) post radiotherapy. Early radiation exposure has been linked to higher rates of fat necrosis and unpredictable volume loss, potentially necessitating further reconstruction.² Some plastic surgery units therefore favour delayed breast reconstruction (DBR) over IBR for patients requiring PMRT. Nonetheless, IBR has firm advantages over a delayed approach including superior aesthetic results, increased patient self-esteem, avoidance of multiple-staged procedures and reduced psychosocial impact of having a mastectomy alone.^3,4

While there is increasing evidence to suggest that immediate implant-based reconstruction is more negatively impacted by radiotherapy⁵, outcomes for autologous tissue flaps remain unclear. With the widening indications for PMRT and breast reconstruction, it is crucial to clarify the true morbidity of radiation on immediate autologous breast reconstruction.

I recently conducted a systematic review with the objective of thoroughly analysing current literature to compare autologous flaps exposed to PMRT to those with no radiation exposure.

MEDLINE, EMBASE and CENTRAL databases were searched. Primary outcomes of interest were the incidence of clinical complications, observer-reported outcomes and patient-reported satisfaction rates. Meta- analyses were conducted to obtain the pooled risk ratio of individual clinical complications where possible.

Twenty-one articles involving 3817 patients were identified. Ten studies recommended IBR, five studies recommended DBR, while six made no explicit recommendations. Meta-analysis of pooled data gave risk ratios for fat necrosis (RR = 1.91, p < 0.00001), secondary surgery (RR =1.62, p = 0.03) and volume loss (RR = 8.16, p < 0.00001) favouring unirradiated flaps, but no significant difference in all other reported complications. The no PMRT group scored significantly higher in observer-reported outcome measures. However, self-reported aesthetic and general satisfaction rates were similar between the patient groups.

The results of my systematic review revealed comparable risks of clinical outcomes in irradiated and unirradiated autologous flaps. Whilst there are statistically significantly higher risks of fat necrosis, volume contracture and secondary surgery, this may not always translate into clinical significance, as corroborated by the high satisfaction rates reported by patients in which these complications developed. Although subjective, a patient’s opinion of her own breast is perhaps the most important measure of success for breast reconstruction. Indeed, studies have shown that patient quality of life is relatively insensitive to the development of complications, and aesthetic self-evaluation scores are often higher than those given by experts.⁶

The meta-analysis demonstrated a significantly higher risk of developing fat necrosis in the irradiated groups. However, evidence suggests that where PMRT has been associated with higher incidence of fat necrosis, radiation itself was often not the cause – rather, it exacerbated firmness, contracture and discomfort in pre-existing areas of fat necrosis.^7,8 This emphasises the need for careful assessment of congestion so that only well-vascularised tissue is preserved in the flap. Studies have shown that using intraoperative indocyanine green angiography to evaluate flap perfusion significantly decreases the odds of fat necrosis in microsurgical breast reconstruction by removing areas with poor blood circulation, simultaneously preventing poor wound healing and skin flap necrosis.⁹

Evolution of radiotherapy techniques may help minimize some of the reported aesthetic complications such as contracture, often linked to PMRT. Modern 3D conformal have been shown to optimise the prescription of isodose to the target volume while reducing exposure to adjacent healthy tissues. Advancements in treatment planning computer algorithms allow modulation of beam intensity within the target to minimise ‘hot spots’ in the reconstructed flap that could increase the risk of late fibrosis and contracture.¹⁰

In conclusion, immediate breast reconstruction should always be offered to patients as a viable option, even in the setting of adjuvant PMRT. When informing the patient on treatment options, equal emphasis should be placed on the benefits and risks of each strategy, and the unpredictability of how an individual patient could respond to treatment. Patients will then be able to judge for themselves which treatment sequence would personally be better for them, facilitating shared decision making and patient-centered care. Patient expectations, preferences, motivations and level of understanding should also be properly managed to enhance postoperative well-being.

References

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8. He S, Yin J, Robb GL, Sun J, Zhang X, Li H, et al. Considering the Optimal Timing of Breast Reconstruction With Abdominal Flaps With Adjuvant Irradiation in 370 Consecutive Pedicled Transverse Rectus Abdominis Myocutaneous Flap and Free Deep Inferior Epigastric Perforator Flap Performed in a Chinese Oncology Center: Is There a Significant Difference Between Immediate and Delayed? Ann Plast Surg. 2017;78(6):633-640.
9. Momeni A, Sheckter C. Intraoperative Laser-Assisted Indocyanine Green Imaging Can Reduce the Rate of Fat Necrosis in Microsurgical Breast Reconstruction. Plast Reconstr Surg. 2020 Mar;145(3):507e-513e. doi: 10.1097/PRS.0000000000006547. PMID: 32097299.
10. Clarke-Pearson EM, Chadha M, Dayan E, Dayan JH, Samson W, Sultan MR, et al. Comparison of irradiated versus nonirradiated DIEP flaps in patients undergoing immediate bilateral DIEP reconstruction with unilateral postmastectomy radiation therapy (PMRT). Ann Plast Surg. 2013;71(3):250-4.