CT staging in breast cancer: Can we select patients requiring staging with CT?

Abstract

BackgroundOne-in-nine women in the UK will develop breast cancer. Current estimates suggest 5% of women presenting with breast cancer will have metastases at the time of diagnosis and 35% will develop metastases within 10-years of diagnosis. At present, no firm guidelines indicate which patients should undergo staging CT: cancer units use local criteria to select patients for CT, meaning some patients undergo unnecessary investigations and exposure to ionising radiation. AimsWhich patients are most likely to have metastases and what characteristics determine whether to CT stage? MethodsData regarding patient and tumour characteristics was retrospectively collected from Equest and CRIS databases on patients who had a CT staging investigation at Southampton Breast Screening Unit during a 4-year period. Results114 patients were eligible for analysis. 21 had distant visceral metastases confirmed by CT. Statistically significant (p≤0.05) relationships were found with axillary lymph node involvement on ultrasound and biopsy results of tumour size (pT) (OR 2.078, 95% CI 1.166–3.704), mammographic size (OR 1.04, 95% CI 1.011–1.069), pre-CT stage (OR 18.831, 95% CI 2.391–148.287) with the existence of metastases on staging CT.The most common reason for CT staging was axillary lymph node involvement on ultrasound with 56.5% with metastases being staged for this reason. Incidence of metastases increased from 3.64% in early stage disease to 13.33% in late stage disease. ConclusionCT is a highly effective staging investigation; however, involves exposure to ionising radiation and financial costs. These results indicate staging CT may not be required in all cases and could be restricted to those patients most at risk from metastases, including patients with late stage disease, axillary lymph node involvement on ultrasound and large tumours. Our results suggest a prompt review of current breast cancer staging guidelines is required to ensure regional consistency in patient selection for CT staging of breast cancer.