Australasian experience and trials in sentinel lymph node biopsy: the RACS SNAC trial

Sentinel lymph node biopsy (SLNB) has been rapidly adopted by surgical oncologists in the management of invasive breast cancer. This study reviews the Royal Australasian College of Surgeons (RACS) Sentinel Node versus Axillary Clearance (SNAC) trial and reports an interim analysis of the first 150 subjects. Other currently open multi-institutional randomized trials in SLNB are reviewed.

The SNAC trial is a multicentre, centrally randomized, phase III clinical trial. Subjects are randomized to SLNB alone (with completion axillary clearance, AC, for sentinel node-positive patients) or AC plus SLNB, with stratification according to age (< 50 years, more than or equal to 50 years), primary tumour palpability (palpable vs impalpable), lymphatic mapping technique (blue dye plus scintigraphy vs blue dye alone) and centre.

The trial was launched in May 2001 in two centres. Randomization continues currently at the rate of approximately 30 subjects per month (total, 1,012 at the time of writing) from 32 participating centres in Australia and New Zealand. Data from the first 150 subjects have been analysed to assess: compliance with randomized treatment allocation; measures of test performance for SLNB (detection, removal, sensitivity, specificity and false-negative rates); measures of arm volume, function, symptoms and quality of life; and sample size estimates.

The SNAC trial is one of the fastest accruing clinical trials in Australasia. It is on track to determine whether differences in morbidity, with equivalent cancer-related outcomes, exist between SLNB and AC for women with early breast cancer.