Objectives

The therapeutic relevance of enhanced sensitivity in detection of lymph node metastases has to be considered in the light of increased morbidity versus eventual prognostic improvements by modification of therapy. An interesting concept which might improve diagnostic accuracy while reducing operative morbidity is the "sentinel node" technique. The sentinel lymph node is the first lymph node to receive the lymphatic drainage from a primary tumour. Conducted using vital dye or visualisation would indicate that this concept can be successfully applied to the management of mammary tumours. (1) The immunohistochemical detection of cytokeratin positive disseminated tumour cells in lymph nodes can help to obtain a more exact identification of patients with an unfavourable prognosis. The use of immunohistochemistry can change the status of a negative node to a positive node in 5-20% of the sample tested, and thus inclusion of an immunohistochemical evaluation may reduce the false-negative rate of the sentinel node technique to almost zero (2). Aims and scope of our experiments to demonstrate the role of detection of sentinel lymph node in diagnosis, therapy and follow up of canine mammary tumours.

Materials & Methods

54 patients (dog and cats) with mammary tumours were examined.

1.  Three-six hours before surgical removal of tumours 20-37 MBq/0,1mL Tc-99m HSA colloid (Senti-Scint^®) was injected subcutaneous. Gamma camera imaging (Nucline X-ring) was used for localizing sentinel nodes.

2.  The nanocolloid size (5 nm diameter) blue dye was subcutaneous injected in four points around the primer tumour immediately before operation.

3.  AE1/AE3 immunostain were occur after remove of primer tumours and of visualised lymph nodes.

Results

Sentinel lymph nodes were localized by Patent blue dye in twenty four (44%) patients. Fourteen (60% of visualized ln) lymph nodes and fourth six (78%) tumour were immunohistochemically cytokeratin positive stained by AE1/AE3. Malignancy (30 patients 57%), inflammation (13 patients 24%), metaplasia (16 patients 30%), and infiltration (10 patients 18%) were examined beside the visualisation of lymph nodes. Both sides of mammary line was affected in 41% of patients, right side was affected in 44% of patients and only left side was affected in 14% of patients. Eighteen sentinel lymph nodes in the 14 oncological dog patients were localized by using the combined method. Thirteen of the nodes (72%) were found to be painted by the blue stain intraoperatively. Only 12 lymph nodes (67%) were clearly identified by gamma camera imaging and 10 (55%) were palpable before surgery.

Conclusions

Palpation, blue stain localizing method and gamma camera imaging alone resulted not satisfactory data on sentinel lymph node detection. Intraoperative radioactive guided surgery combined with blue stain seems to be the superior method for localizing sentinel lymph nodes in dogs like in human beings. The dye is a choice for detection of distant metastases which indicates the lower incidence of residues. The use of immunohistochemistry can change the status of a negative node to a positive node in 5-20% of the sample tested, and thus inclusion of an immunohistochemical evaluation may reduce the false-negative rate of the sentinel node technique to almost zero.

References

1.  Giuliano AE, Dale PS, Turner RR, et al. Improved axillary staging of breast cancer with sentinel lymphadenectomy. Ann Surg 1995, 222: 394-401.

2.  Giuliano AE, Jones RC, Brennan M, Statman R. Sentinel lymphadenactomy in breast cancer. J Clin Oncol 1997, 15: 2345-2350.