Medico-economic Study of Three Strategies of Sentinel Lymph Node Analysis in Operable Breast Cancer

Breast carcinoma requires frequently an adjuvant therapy after surgical excision: in this way, one of the major criteria indicating the need of adjuvant chemotherapy is the diagnosis of a metastatic lymph-node invasion, mainly in the axillary field. Axillary surgery is therefore mandatory at the diagnosis of breast carcinoma. For many years, in order to avoid unnecessary complications due to extensive axillary surgery (for instance, arm enlargement by lymphedema), a limited surgery is frequently performed on the first supposed invaded lymph-nodes (LN) called "sentinel" LN technique; if the sentinel LN are not invaded, extensive axillary surgery can be omitted. To decide it during the surgery, removed sentinel LN are cut in 3 to 4 slices which are examined immediately as smears (cytology) or frozen slices (pathology). However, due to hazard in cutting the LN, micro-metastases can be misdiagnosed. That is why a recent molecular biology method has been developed in which the total LN are crushed and blended, then analyzed by OSNA technique (One Step Nuclear Acid analysis) so as to amplify and detect the mRNA coding for cytokeratin-19 protein witnessing the LN metastatic invasion. A standardized automated technique is available with a mean time of 30 to 50 minutes according to the number of analyzed LN. In 12 international studies (2830 cases) the consistency between OSNA technique and final pathology is of 91 to 98% and the sensitivity seems higher. Less than 5% of all breast carcinomas cells don't express CK-19 protein. The use of OSNA technique requires a dedicated machine and a skilled pathologist, increasing slightly the operation time; however it allows to avoid the immediate and long-term complications due to the radical LN axillary surgery in case of negativity of the sentinel LN procedure. To date, the three techniques including extemporaneous examinations (OSNA or classical methods) or not (classical pathological analysis) have their own advantages and drawb