Utility of systemic staging in breast cancer patients with a positive sentinel lymph node biopsy

TL;DR

This study finds that systemic CT scans do not detect distant metastases in breast cancer patients with small axillary metastases.

Contribution

The study provides evidence that systemic staging is unnecessary for patients with micrometastatic axillary disease.

Findings

Systemic CT staging detected distant metastases in only 2% of patients with macrometastases.

No patients with micrometastases had metastatic disease detected by systemic CT.

Further imaging was often required but rarely led to actionable findings in micrometastatic cases.

Abstract

CT thorax, abdomen and pelvis (CT-TAP) remains the standard in the identification of metastatic disease in patients with newly diagnosed breast cancer. In patients with proven micro and macro axillary nodal metastasis, the optimal radiological technique remains controversial. A consensus on which patients with axillary nodal disease should receive radiological staging for distant disease and how this should be performed is not currently available. The aim of this study was to evaluate the yield from CT staging of the thorax, abdomen and pelvis (CT-TAP) in patients with proven nodal disease.

Patients diagnosed with invasive breast cancer with a positive sentinel lymph node biopsy (SLNB) and subsequent staging CT-TAP between 2013 and 2017 were identified. Patient demographics, clinicopathological characteristics, CT-TAP findings and further imaging requirements were documented.

A total of 234 patients were identified. Of these, 164 (70%) were found to have macrometastasis and 70 (30%) to have micrometastasis or isolated tumour cells on SLNB. Within the macrometastasis cohort, abnormalities were noted on staging CT-TAP for 100 (61%) patients. Eighty of the 100 received follow-up assessment of abnormalities with 3 (2%) patients being diagnosed with distant metastatic disease. Within the micrometastasis group, abnormalities on CT-TAP staging were noted in 36 (52.1%) patients. Twenty-eight (40%) patients required further investigation and follow-up. No patient was found to have metastatic disease within this group.

Patients diagnosed with micrometastatic disease of the axilla following a sentinel lymph node biopsy do not require systemic staging as it fails to detect metastatic disease.