Impact of post mastectomy radiotherapy on the silicone breast implant.

Implant based reconstruction accounts for over half of breast reconstruction performed in the UK. Patients with implant based breast reconstructions undergoing post mastectomy radiotherapy are at increased risk of capsular contracture and reconstructive failure. This study sought to determine the effect of treatment dose radiotherapy on the bulk mechanical, surface chemical properties of silicone implants as well as their cellular response. Silicone breast implant shells were submitted to treatment dose radiotherapy, 2.67 Gy (one daily fraction) and 40.05 Gy (15 fractions) using non-irradiated shells as controls. Bulk mechanical and surface chemical properties of the shells were evaluated using tensile and tear testing, attenuated total reflectance - fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements. HDFa cells were seeded on the shells and Alamar Blue assay was performed to study cell metabolic activity. Cell morphology was evaluated using phalloidin and DAPI staining. There was no significant difference in tensile, tear strength and Young's modulus however there was reduction in maximum elongation following irradiation. Irradiation of the shells did not significant alter spectroscopy measurements nor wettability of the shells. Cell metabolism was not significantly affected by irradiation. Further analysis is warranted of the micromechanical properties to fully elucidate the effect of irradiation on the breast implant which could explain the increased rate of capsular contracture and reconstructive failure in patients undergoing post-mastectomy radiotherapy.