Variations in the management of the axilla in screen-detected ductal carcinoma in situ: evidence from the UK NHS breast screening programme audit of screen detected DCIS.

ABSTRACT

The diagnosis and surgical management of screen-detected Ductal Carcinoma In Situ (DCIS) remains controversial including a range of axillary approaches and consequent morbidity. This study examined the management of the axilla in all patients with DCIS presenting through the United Kingdom National Health Service Breast Screening Programme (UK NHS BSP). Retrospective analysis of the UK NHS BSP identified 26,696 women initially diagnosed with DCIS over the 8 years 1 April 2003-31 March 2011. The final breast pathology of these women was upgraded to invasive ductal cancer in 5564 (20.8%) women or micro-invasive cancer in 1031 (3.9%) women. At first operation, 5290 (26.3%) of the 20,094 women who had a final post-operative diagnosis of DCIS only underwent axillary surgery (72.4% at the time of mastectomy, 23.8% breast conservation surgery, 3.8% axillary surgery alone). Performance of axillary surgery reflected increasing tumour size, micro-invasion or increasing nuclear grade for the final diagnosis of DCIS. More extensive nodal surgery was performed in those undergoing mastectomy; 10.8% of women had more than 8 nodes removed. Overall, 12.0% of women with invasive cancer, 1.7% with micro-invasion, and 0.2% with DCIS alone, were ultimately node positive. Improved pre-operative sampling of DCIS, axillary assessment by ultrasound with needle biopsy for suspected metastases, risk stratification for sentinel node biopsy (for high grade or extensive DCIS) and avoiding axillary clearance for a pre-operative diagnosis of DCIS alone should reduce unnecessary axillary surgery. Standards using such criteria for axillary surgery in screen-detected DCIS should be integrated into the NHS BSP.