Main Session
Sep
28
PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology
Presenter(s)
Vishnu Dubakula, DO - Baylor Scott, Round Rock, TX
V. V. Dubakula1, V. Nguyen2, R. Surapaneni1, C. Murray1, M. Dubin1, O. Vyas1, S. I. Anne1, A. Kucharska1, C. Young1, R. Aschenbeck1, and P. Gabani1; 1Baylor Scott & White Health, Round Rock, TX, 2Texas A&M University School of Medicine, Bryan, TX
Purpose/Objective(s):
Axillary ultrasound is increasingly used to stage the axilla in early-stage breast cancer. Trials such as SOUND and INSEMA suggest sentinel lymph node biopsy may be omitted in selected patients with negative axillary ultrasound, potentially reducing surgical morbidity. However, the false-negative rate remains a critical determinant of reliability. We examined these trial findings within our own institution to determine their applicability to our patient population and inform treatment planning. We evaluated the false negative rate of preoperative axillary ultrasound in patients with small and early-stage breast cancer to assess accuracy and inform de-escalation strategies.Materials/Methods:
We conducted a retrospective single-institution review of patients from January 2022 to December 2024 with histologically confirmed breast cancer (<5 cm) and negative preoperative axillary ultrasound. Patients with suspicious nodes, multifocal disease, tumors >5 cm, concurrent malignancies, triple negative cancer, HER-2 amplification were excluded. All patients underwent sentinel lymph node biopsy for pathologic correlation. The primary endpoint was false negative rates, defined as negative axillary ultrasound with positive sentinel lymph node biopsy. Clinicopathologic variables including tumor size, grade, receptor status, and Oncotype risk were analyzed descriptively, with chi-square testing for association between tumor size and nodal positivity.Results:
A total of 158 patients met inclusion criteria, consisting of postmenopausal women aged 50 years and older. Sentinel lymph node biopsy identified nodal metastases in 22 patients, including 3 cases with isolated tumor cells, corresponding to an overall false negative rate of 13.75% (95% CI, 9.3–19.9%). Nodal positivity increased with clinical tumor size: no patients in T1a, 6.7% (2/30) in T1b, 18.6% (10/55) in T1c, and 19.6% (10/51) in T2 tumors. However, tumor size was not significantly associated with sentinel lymph node positivity (?²(3)=2.55, p=0.47). Tumor grade demonstrated no consistent trend, with nodal involvement in 21.4% (6/28) of grade 1, 17.7% (14/79) of grade 2, and 7.4% (2/27) of grade 3 tumors. No association was observed across Oncotype risk categories, with nodal positivity in 22.8% (13/57) of low-risk, 28.5% (6/21) of intermediate-risk, and 0% of high-risk tumors.Conclusion:
In this institutional cohort of early-stage breast cancer patients with negative axillary ultrasound, the false negative rate was consistent with our hypothesis. Although higher rates were observed in larger tumors, statistical significance was not reached, likely reflecting sample size limitations. Notably, the confidence interval suggests the true rate may be meaningfully higher, indicating that some patients may still harbor occult nodal disease. These findings emphasize risk-stratified selection when considering omission of sentinel lymph node biopsy at both institutional and individual levels.