Prevalence of Overt Metastases in Locally Advanced Breast Cancer

Abstract 

Aims

Locally advanced breast cancer (LABC) represents a wide spectrum of clinical presentations and poses significant clinical challenges for both patients and their physicians. Before starting neoadjuvant therapy, most patients undergo staging investigations, including a radioisotope bone scan, liver ultrasound and chest X-ray as per our provincial guidelines. The aim of this study was to document the prevalence of metastatic disease using standard baseline radiological staging in patients with LABC.

Materials and methods

A retrospective chart review was carried out for LABC patients at two large Canadian centres between 2003 and 2006. Data on tumour characteristics and baseline staging tests were collected. Information on any confirmatory imaging (bone X-ray, computed tomography, magnetic resonance imaging, positron emission tomography) undertaken due to the presence of suspicious baseline tests or due to worrying symptoms was also obtained. The prevalence of metastatic disease after each baseline imaging technique was analysed, as was the frequency of discordance between baseline staging tests and confirmatory imaging where applicable.

Results

In total, 144 patients with LABC were assessed. After initial staging investigations, 15 patients (10.4%) were diagnosed as having overt metastatic disease. Confirmatory imaging was carried out on 19 patients (13.2%); five (3.5%) for unexplained symptoms and 14 (9.7%) due to equivocal baseline imaging. These additional investigations isolated a further four subjects with metastatic disease, bringing the overall prevalence of overt metastases to 13.2%.

Conclusions

Given that the rate of systemic relapse in patients with LABC is very high, current baseline staging investigations probably underestimate the true incidence of metastases. This study has shown that further confirmatory imaging can be helpful, especially in symptomatic patients, as it seems that negative baseline tests in these patients can be falsely reassuring. Accurate staging of patients with LABC has many advantages and, therefore, further research is needed to define the role of newer imaging modalities.

Key words: Imaging, locally advanced breast cancer, metastases, staging