E49: Survival Outcomes in Patients with de novo Stage IV Breast Cancer after Primary Tumor Resection

Author(s)

Shruti Zaveri, MD (she/her/hers)

Staff Surgeon
UT Southwestern Medical Center
Houston, Texas, United States

ePoster Abstract Author(s)

Jennifer H. Chen, MD

Research Resident
University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Submitter(s)

Jennifer H. Chen, MD

Research Resident
University of Texas MD Anderson Cancer Center
Houston, Texas, United States

Author(s)

AA

Abdulkader Almosa, n/a

Research Intern
University of Houston MD Anderson Cancer Center, United States
SM

Salyna Meas, n/a

Research Assistant
University of Texas MD Anderson Cancer Center, United States
ZY

Zixi Yang, MSPH

Graduate Research Assistant
University of Texas MD Anderson Cancer Center, United States
SK

Suprateek Kundu, PhD

Associate Professor
Department of Biostatistics, University of Texas MD Anderson Cancer Center, United States
Anthony Lucci, Jr., MD

Professor
Department of Breast Surgical Oncology, MD Anderson Cancer Center, Houston, TX, USA
Houston, Texas, United States

Introduction: The role of surgical resection remains controversial in the management of de novo stage IV breast cancer. We sought to evaluate outcomes in patients with de novo stage IV disease to determine which subset of patients may benefit most from surgery.

Methods: All patients with de novo stage IV breast cancer who underwent surgery of the primary breast tumor from 2014-2022 were retrospectively identified from a prospectively maintained database. Kaplan-Meier method and log-rank test were used for survival analysis.

Results: In total, 165 patients with de novo stage IV disease underwent surgical resection. The median age at diagnosis was 48 years (IQR 31-58), and BMI was 28 kg/m2 (IQR 24-32). Majority of patients had T4 (87, 52.7%), node-positive (146, 88.5%), HR-positive, and HER2-negative disease (78, 71.5% and 109, 66.1%). Level of metastatic burden was categorized as solitary (67, 40.6%), oligometastatic (2-4 sites, 53, 32.1%), and multiple (>4 sites, 45, 27.3%). The most common metastatic sites included bone (83, 80.3%), soft tissue/lymph nodes (41, 24.8%), liver (34, 20.6%), and lung (33, 20%). Surgical management of the primary tumor consisted predominantly of total mastectomy (138, 83.6%) and less commonly, lumpectomy (26, 15.8%). Most patients underwent axillary surgery: sentinel lymph node biopsy alone (14, 8.5%) and axillary lymph node dissection (ALND) (109, 66.1%). The median follow-up period was 49 months (IQR, 23-76). There was no significant difference in OS or PFS by age, race/ethnicity, surgical margin status, ALND, nodal disease burden, and presence of lymphovascular invasion. Compared to solitary and oligometastatic disease, patients with multiple metastases had significantly inferior OS and PFS (median OS: 100.6 and 143.7 vs. 56.5 months, respectively, p = 0.046). Patients with triple-negative disease had significantly worse OS and DFS while those with HR-positive/HER2-positive disease had the best prognosis (p < 0.0001 for both). Incorporation of adjuvant radiotherapy to primary tumor site was associated with significantly improved OS and PFS (median 143.7 vs. 56.8 months, p = 0.017).

Conclusions: Long-term survival can be achieved in select patients with de novo stage IV breast cancer treated with multimodal therapy. Among those who undergo primary tumor resection, low metastatic burden, HER2-positive disease, and adjuvant RT are associated with improved survival outcomes. Surgical resection of primary tumor in these patients may be considered to maximize survival benefit.

Learning Objectives:

Describe the potential role of surgery in management of patients with de novo stage IV breast cancer.
Determine which breast cancer subtypes may potentially benefit most from surgical resection of primary tumor in patients with de novo stage IV breast cancer.
Evaluate the impact of metastatic burden on overall survival and progression-free survival in patients who undergo surgery for de novo stage IV breast cancer.