Bethany M Anderson1, Mitchell Kamrava2, Pin-Chieh Wang2, Peter Chen3, D Jeffrey Demanes2, John K Hayes4, Robert R Kuske5. 1. Department of Human Oncology, University of Wisconsin, Madison, WI. Electronic address: anderson@humonc.wisc.edu. 2. Department of Radiation Oncology, UCLA Health, Los Angeles, CA. 3. Department of Radiation Oncology, William Beaumont Hospital, William Beaumont School of Medicine, Oakland University, Royal Oak, MI. 4. Gamma West Cancer Services, Salt Lake Regional Medical Center, Salt Lake City, UT. 5. Arizona Breast Cancer Specialists, Scottsdale, AZ.
Abstract
PURPOSE: To determine in breast tumor recurrence (IBTR) and regional nodal recurrence (RNR) rates for women treated with multicatheter interstitial accelerated partial breast irradiation. METHODS AND MATERIALS: Data from five institutions were collected for patients treated from 1992 to 2013. We report outcomes of 582 breast cancers with ≥1 year of followup. Molecular subtype approximation was performed using estrogen receptor, progesterone receptor, Her2, and grade. The Kaplan-Meier method was used to calculate overall survival, IBTR, RNR, and distant recurrence rates. Univariate and multivariate Cox proportional hazard models were performed to estimate risks of IBTR and RNR. RESULTS: With a median followup time of 5.4 years, the 5-year IBTR rate was 4.7% overall, 3.5% for Luminal A, 4.1% for Luminal B, 5.2% for Luminal Her2, 13.3% for Her2, and 11.3% for triple-negative breast cancer. Positive surgical margins and high grade were associated with increased risk for IBTR, as was Her2 subtype in comparison with Luminal A subtype. Other individual subtypes comparisons did not show a significant difference. Analysis of Luminal A vs. all other subtypes demonstrated lower IBTR risk for Luminal A (5-year IBTR 3.5% vs. 7.3%, p = 0.02). The 5-year RNR rate was 2.1% overall, 0.3% for Luminal A, 4.6% for Luminal B, 2.6% for Luminal Her2, 34.5% for Her2, and 2.3% for triple-negative breast cancer. RNR risk was higher for women with Her2 compared to the other four subtypes and for Luminal B compared to Luminal A subtype. CONCLUSIONS: Molecular subtype influences IBTR and RNR rates in women treated with multicatheter interstitial accelerated partial breast irradiation. Copyright Â
PURPOSE: To determine in breast tumor recurrence (IBTR) and regional nodal recurrence (RNR) rates for women treated with multicatheter interstitial accelerated partial breast irradiation. METHODS AND MATERIALS: Data from five institutions were collected for patients treated from 1992 to 2013. We report outcomes of 582 breast cancers with ≥1 year of followup. Molecular subtype approximation was performed using estrogen receptor, progesterone receptor, Her2, and grade. The Kaplan-Meier method was used to calculate overall survival, IBTR, RNR, and distant recurrence rates. Univariate and multivariate Cox proportional hazard models were performed to estimate risks of IBTR and RNR. RESULTS: With a median followup time of 5.4 years, the 5-year IBTR rate was 4.7% overall, 3.5% for Luminal A, 4.1% for Luminal B, 5.2% for Luminal Her2, 13.3% for Her2, and 11.3% for triple-negative breast cancer. Positive surgical margins and high grade were associated with increased risk for IBTR, as was Her2 subtype in comparison with Luminal A subtype. Other individual subtypes comparisons did not show a significant difference. Analysis of Luminal A vs. all other subtypes demonstrated lower IBTR risk for Luminal A (5-year IBTR 3.5% vs. 7.3%, p = 0.02). The 5-year RNR rate was 2.1% overall, 0.3% for Luminal A, 4.6% for Luminal B, 2.6% for Luminal Her2, 34.5% for Her2, and 2.3% for triple-negative breast cancer. RNR risk was higher for women with Her2 compared to the other four subtypes and for Luminal B compared to Luminal A subtype. CONCLUSIONS: Molecular subtype influences IBTR and RNR rates in women treated with multicatheter interstitial accelerated partial breast irradiation. Copyright Â
Authors: Matthew N Mills; Nicholas W Russo; Matthew Fahey; Ronica H Nanda; Sunny Raiker; Jessica Jastrzebski; Lisa L Stout; Jason P Wilson; Taghrid A Altoos; Kathleen G Allen; Peter W Blumencranz; Roberto Diaz Journal: Oncologist Date: 2021-10-04