L. L. Frasier1, S. E. Holden1, T. R. Holden2, J. R. Schumacher1, G. Leverson1, B. M. Anderson3, C. C. Greenberg1, H. B. Neuman1,4 1University Of Wisconsin,Wisconsin Surgical Outcomes Research Program, Department Of Surgery,Madison, WI, USA 2University Of Wisconsin,Department Of Medicine,Madison, WI, USA 3University Of Wisconsin,Department Of Human Oncology,Madison, WI, USA 4University Of Wisconsin,Carbone Cancer Center,Madison, WI, USA
Introduction: : Research suggests an inverse relationship between post-mastectomy radiation (PMRT) and immediate breast reconstruction (IR). Recent data on the effectiveness of PMRT has led to increasing use in patients at intermediate risk (tumor ≤ 5cm with 1-3 positive nodes) of recurrence. At the same time, significant increases in the use of IR over the last decade have been observed. We sought to determine whether the increased use of PMRT in intermediate risk patients has led to a slower increase in rates of IR when compared to groups in whom the guidelines for PMRT have not changed.
Methods: The SEER Database was used to identify female patients with stages I‑III breast cancer undergoing mastectomy over the decade from 2002‑2011 (n=40,889). Patients ≥ 65 were excluded due to low rates of IR (5.1%). Three patient cohorts defined by likelihood of PMRT were formed based on tumor characteristics: High Likelihood (four or more positive lymph nodes or tumors >5 cm with 1‑3 positive lymph nodes), Intermediate Likelihood (tumors ≤5 cm with 1‑3 positive lymph nodes), and Low Likelihood (tumors ≤5 cm with 0 positive nodes). Changes in IR for each of these groups over time were assessed using joinpoint regression and summarized using annual percentage change (APC), which represents the slope of the line.
Results: The overall use of reconstruction increased from 22% in 2002 to 41% in 2011. This statistically significant increase was observed across all 3 cohorts defined by the likelihood of receiving PMRT and across all ages. Receipt of IR was lower among groups with a higher likelihood of a recommendation for PMRT at the start of the study period: 14.1%, 19.4%, and 27.8% in the High, Intermediate, and Low Likelihood cohorts, respectively, in 2002. The highest risk group demonstrated the most increase in receipt of IR, as evidenced by its annual percentage change of 9.8%, with intermediate and low risk exhibiting APCs of 6.2% and 5.9%, respectively. No group showed a significant change in APC from 2002-2011, meaning the rate of change was constant over the study period.
Conclusion: Rates of reconstruction have increased over the study period across tumor characteristics and are highest in patients that are least likely to receive a recommendation for PMRT. At no point did any group exhibit any evidence of a decreased rate of change, despite increased indications for PMRT over this time period. In fact, rates of IR for patients at intermediate and high likelihood of receiving PMRT are increasing faster than rates for the lowest-likelihood patients. This may indicate that surgeons and radiation oncologists are becoming increasingly more comfortable with the prospect of immediate reconstruction in the setting of anticipated PMRT.