Presenter(s)
Y. Ramdas1, T. J. Quinn1, T. Reinicke2, N. Tayeb3, C. T. S. Liu4, J. S. Stromberg1, M. S. Jawad1, G. S. Gustafson5, M. D. Johnson6, N. Dekhne5, S. H. Kiran5, J. C. Selber5, and J. T. Dilworth7; 1Department of Radiation Oncology, Corewell Health William Beaumont University Hospital, Royal Oak, MI, 2Oakland University William Beaumont School of Medicine, Rochester, MI, United States, 3Corewell Health - William Beaumont University Hospital, Royal Oak, MI, 4Campbell University School of Osteopathic Medicine, Buies Creek, NC, 5Corewell Health William Beaumont University Hospital, Royal Oak, MI, 6Department of Radiation Oncology, McLaren Macomb, Mount Clemens, MI, 7Corewell Health William Beaumont University Hospital, Royal Oak, Royal Oak, MI
Purpose/Objective(s): There has been reluctance to offer direct-to-permanent-implant (DTI) potential predictors of implant failure (IF) in patients receiving PMRT with two-stage reconstruction with tissue expander placement (TE) or DTI.
Materials/Methods: We included patients at a single institution who underwent a mastectomy with either TE or DTI and received PMRT from 1/2019 to 6/2025. Continuous variables were compared using Wilcoxon rank sum tests; categorical variables were compared using Pearson chi square or Fisher exact tests. Time to event outcomes were estimated using the Kaplan Meier method and compared using log rank tests. Associations between patient/treatment factors and binary outcomes were assessed using logistic regression modeling. Univariable and multivariable models were constructed to identify independent predictors of event outcomes. Significance and borderline significance were defined as a p value <0.05 and <0.10, respectively.
Results: We identified 171 patients who received PMRT to the chest wall with either a tissue expander (n=111) or permanent implant (n=60). Patients self-identified as White (n=127), Black (n=28), or other (n=16). The majority (95%) of patients received nodal irradiation. PMRT was conventionally fractionated in 143 (84%) and moderately hypofractionated in 28 (16%). For 150 patients (88%) who received photon treatment, bolus was used in 105 (70%). For 21 patients (12%) who received proton treatment, a skin rind was contoured and used as an optimization parameter to minimize near-surface dose. Median follow up (IQR) was 42 months (25,65) for all patients, 55 months (38,76) for patients with TE, and 28 months (17,36) for patients with DTI (TE vs. DTI p<0.001). The probability at 5 years of an unplanned reconstructive surgery (with preservation of the implant) was 30.7% for all patients and similar between TE and DTI (p=0.9). The probability at 5 years of IF was 8.6% for all patients, 10% for patients with TE, and 4.5% for patients with DTI (TE vs. DTI, p=0.31). Median time (IQR) to IF was 17 months (7,26 months) for all patients and similar between those with TE and DTI (p=0.9). Diabetes mellitus (DM), non-White/Black race, grade =2 chest wall pain, and the development of moist desquamation were independent predictors of IF with OR of 7.7 (1.34,45.9, p=0.02), 7.1 (1.29,39.8, p=0.02), 6.1 (1.25,45.2, p=0.04), and 3.7 (0.81,18, p=0.09). No patient who received proton therapy had an IF. Radiation fractionation type did not predict for IF.
Conclusion: Rates of IF and unplanned reconstructive surgery were not higher in patients with DTI, compared to those with TE. Management of DM and minimizing dose to the near-surface region are prudent for avoiding complications with breast reconstruction.