Surgical intervention in screen-detected patients versus symptomatic patients with breast cancer.

OBJECTIVES: The impact of population-based screening for breast cancer on the rate of breast-conserving surgery has not been established. We sought to evaluate whether surgical intervention in patients with screen-detected breast cancer differed from those with clinically detected tumours. SETTINGS: St Vincent's University Hospital and the BreastCheck Merrion Unit, part of the Irish National Breast Screening Programme, were the setting for the study.
METHODS: A total of 902 patients referred for surgery to St Vincent's University Hospital over a four-year period (2000-2003) were studied. Patients with breast cancers detected during the prevalent round of screening (n=325) were compared with patients presenting with symptomatic disease (n=577). The operative procedure, nature of axillary surgery and histopathological findings were recorded in each case.
RESULTS: There was an increase in breast-conserving therapy in the screened population compared with symptomatic cases (68% screened versus 53% symptomatic; p<0.0001), with a corresponding reduction in axillary clearance rates (65% screened versus 81% symptomatic; p<0.0001). Nodal positivity was similar following correction for size in all tumours >1 cm, regardless of method of detection. Sentinel node biopsy was successfully undertaken in 39% of tumours <2 cm (T1 tumours) [corrected] in the screening population.
CONCLUSIONS: The screened population was statistically more likely to have breast-conserving therapy than the symptomatic group. Sentinel node biopsy has evolved into an acceptable alternative to axillary clearance in T1 cancers, particularly in screen-detected cases.