1b. SLN biopsy Flashcards
1
Q
Sentinel lymph node
A
1st lymph node draining fluids from the breast tissue
2
Q
Sentinel lymph node biopsy functions
A
- Predict true pN0 status
- Avoid unnecessary nodes dissection
3
Q
Possible sequelae of extensive LN dissection
A
- Vascular and nervous damage
- impairement of lymph drainage
4
Q
Procedure steps
A
- Injection of labelled human colloidal albumin inside tumor lesion
- lymph is drained trhough the axilla -> 1st drainin node is identified through scintigraphy with a gamma camera
- it is excised surgically
- Double checked for famma emission with a sensitive probe
- Breast tissue is controlled again for the presence of other reactive LNs
5
Q
Safety
A
- It is a safe and effective procedure for the staging of breast cancer
- No proof of superioriy of SLN biopsy on axilla dissection
6
Q
3 main modalities of SLN involvement
A
- Isolated tumor cells (small aggregates <200 um): do not display metastatic activity, risk up to 5% to have additionally axillary met
- Micrometastases (200-2000 um): since if present they have the same risks of ITCs for additionally axillary mets, thus it is not an indication for axillary dissection
- Macrometastases (>2000um) -> indication for axillary dissection
7
Q
Metastatic activity definition
A
Ability of a disseminated lesion to modify the surrounding microenvironment, in particular by inducing fibrosis and desmoplasia and by penetrating vascular compartments.
8
Q
Optimal histopathological assessement
A
- Cancer cells do not have a preferential distribution in the LNs
-> the entire SLN should be sampled and examined through serial sections at regular pre-defined cutting intervals
SInce only macromets are an indication for axillary dissection, cut is usually performed at 2mm
9
Q
Gold standard analysis
A
SLN histopathological assessment Molecular methods (e.g. qPCR) have poor sensitivity so they are not recommended.
