N. S. Muppidi1, M. Yi1, T. Adesoye1, P. Singh1, M. Chavez-MacGregor2,3, M. Karuturi2, S. X. Sun1, N. Tamirisa1, K. K. Hunt1, M. Teshome1 1University Of Texas MD Anderson Cancer Center, Surgery/Breast Surgical Oncology, Houston, TX, USA 2University Of Texas MD Anderson Cancer Center, Cancer Medicine/Breast Medical Oncology, Houston, TX, USA 3University Of Texas MD Anderson Cancer Center, Cancer Prevention And Population Sciences/Health Services Research, Houston, TX, USA
Introduction:
Treatment of early-stage HER2-positive breast cancer has significantly changed given advancements in targeted therapies and recent clinical trials. Current treatment strategies include neoadjuvant systemic therapy (NST) to assess treatment response, or upfront surgery to define pathologic stage and guide systemic therapy. This study investigates the management approach of early-stage node-negative HER2-positive breast cancer and temporal trends.
Methods:
Patients with cT1-2 (clinical tumor size ≤3 cm) N0 M0, HER2-positive invasive breast cancer were identified from an institutional database. All patients received surgery at our institution from 2015-2020. Clinical nodal status was determined by axillary ultrasound. Clinical and treatment characteristics were evaluated and compared between patients who received upfront surgery and NST. The Χ2 and Fisher exact tests were used to compare variables between treatment groups. Additionally, an electronic survey was sent to medical and surgical oncologists at our institution to evaluate current treatment recommendations for clinical scenarios related to this population.
Results:
256 patients were identified over the study period. Upfront surgery was performed in 86.8% (n=167) of cT1 tumors and 28% (n=89) cT2 (≤3 cm) tumors. Patients with cT1mi, cT1a, and cT1b tumors almost always received upfront surgery as well as 81.8% (n=110) with cT1c tumors. NST rates slightly increased from 28% in 2015 to 35% in 2019, with a rapid increase to 62% in 2020 (Figure 1). There was no statistically significant difference between the upfront surgery and NST groups in receipt of segmental mastectomy (68.3% vs 62.8%, p=0.4), or completion axillary lymph node dissection (3.5% vs 2.3%, p=0.7). The survey response rate was 39.3% (n=24; 34.2% medical oncologists (n=13), 45.8% surgical oncologists (n=11)). There was 100% agreement for management of cT1aN0 patients with upfront surgery, and cT2N0 (3-5 cm) and cT1-2N1 patients with NST. There was near agreement (92%) for management of cT1bN0 patients with upfront surgery. For cT1cN0 patients, 45% of physicians recommended upfront surgery and for cT2N0 (<3 cm) patients, 71% recommended NST, without an observed difference by specialty type.
Conclusion:
The majority of patients with cT1-2 (≤3 cm) N0 HER2-positive breast cancer received upfront surgery. The observed increase in NST in 2020 may be partly due to the COVID-19 pandemic. There was no significant difference in surgical management between upfront surgery and NST groups. Variability in management recommendations was observed among survey respondents for cT1c tumors, tending to favor upfront surgery, and cT2(<3cm) tumors, tending to be treated with neoadjuvant systemic therapy.
