Background: The indication for sentinel node biopsy (SNB) has not been fully established yet for patients with ductal carcinoma in situ (DCIS).
Aim: To relate the conversion rate to invasive carcinoma with sentinel node positivity in high risk DCIS, and to refine the clinical presentation analysis in order to better select patients for SNB. For this purpose, a risk score was devised.
Methods: From 1998 to 2005, 151 high-risk DCIS patients from six clinical centres were included in a prospective sentinel node database. The conversion rate to invasive carcinoma was 39%. Ten of 142 (7%) successful SNBs showed a positive sentinel node (eight micrometastatic). The sentinel node was positive in 1% of pure DCIS, in 5.5% of DCIS with micro-invasion, and in 19.5% of invasive carcinoma.
Results: Both clinical presentation and corresponding risk score were closely related to conversion to invasive carcinoma. The association of risk score and sentinel node positivity approached but did not reach statistical significance (P=0.06); therefore a subset of further selected higher risk patients could not be defined.
Conclusion: The relevance of SNB positivity cannot be overlooked in high-risk DCIS patients, however, because SNB is not free from morbidity and cost, more studies are needed to refine its final indication.