Specific Techniques


Sentinel Lymph Node Technique

LINKS
  
Introduction
Validation of the Technique
Inclusion Criteria
Methodology
Follow-up
Technique





INTRODUCTION

The degree of axillary affectation is the most important prognostic factor. Breast cancer tumours are being diagnosed at earlier stages, to the extent that in our PDPCM, approximately 75% of the cases are NO.

Besides, according to the recommendations from the different Saint Gallen consensus, for NO cases a series of prognostic factors are considered that recommend cytostatic systemic treatment even in cases in which the axilla is negative.

We are at a stage of a progressive detection of small sized-tumours, mostly NO cases, in which an unnecessary operation is carried out. The philosophy and clinic evidence of the published research makes us consider the detection technique and lymph node study as useful to determine a subgroup of women that can benefit from the treatment without having to have an operation when the sentinel lymph node is negative.

VALIDATION OF THE TECHNIQUE

We carried out 100 lymph node studies in our hospital between October 1998 and October 2000.

The lymph node was not possible to locate in 8 cases (8%).

Total valid cases: 92
VP:31
FN:1
VN:60
Sensitivity:98%
IC 95%: 79.8-100%
VPN: 99%.


These results comparable to the already published series allow us to validate the data (according to the calculations of our Research Department also authorised by the Hospital of Badalona and with the consulting of the Instituto Catalán de Oncología). We propose to apply this technique within the framework of our guideline.


INCLUSION CRITERIA

  • T1 N0.
  • Extense DCIS, high degree with necrosis.
  • Obesity, breast and axillary volume are assessed.
  • Patient's informed agreement.

METHODOLOGY
  • Carcinoma's pathologic diagnose (Trucut-Mammotomeâ-ABBI).
  • Clinic-radiologic size assessment (mammography+ecography).
  • CDI 2 cm.
  • DCI 4cm with demand of mastectomy.
  • Inform the patient. Agreement.
  • Planning of the preoperatory study and the same day, early in the morning (8:30am):

-Four cardinal points in the breast with TC99.
-Breast Gammagraphy after 2h.
-If (+): local anaesthetic and removal of the lymph node for deferred pathological study (haematoxiline-eosine+Inmunohistochemistry).
-If (-): We assess the possibility of trying again after 24h.
-If (+): We proceed to surgical removal in internal breast chain or other localisations after 24h.

  • 8 days later:
    - Pre-operatory study results.
    - Sentinel lymph node results.

  • Therapeutic strategy planning (Multidisciplinary Breast Unit):
    - If negative lymph node: No axillar surgery (nor radiotherapy), lymphadenectomy or simple mastectomy.
    - If positive lymph node: Conventional treatmet.

  • Complementary treatment: Depending on risk factors (multidisciplinary breast unit).

  • MIBI and/or pre-operatory axillary ecography is assessed.
    		 

     

FOLLEW-UP

The follow-up takes place every 6 months during the first three years at the Breast Unit.

We carry out control axillary ecography and MIBI.

NOTE: In NO T1 NO tumours we continue to determine the sentinel lymph node followed by lymphadenectomy in order to assess its validity and to eventually widen the inclusion criteria to T2NO tumours.



TECHNIQUE

At the Nuclear Medicine Department:

The isotopic marker is an albumin nanocloid with TC99M. The patient is injected 2mCi in a 4ml volume. This total dose is fractioned in 4 aliquots to be injected in 4 localised points around the tumour. Between 1-4 hours after the injection we obtain the images in the gammacamera in anterior, oblique and lateral positions. Once the lymph node is localised we mark the patient's skin.

 

 

At the operating theatre:

We carry out a small cut in the axilla, close to the mark left on the skin. We introduce the Gamma Detection Probe until we localise the area of most incidence. This point coincides with the sentinel lymph node. We remove it and we send it to the Pathology Department. We introduce the probe again in the axilla to check the radioactivity.

 

 

At the Pathology Department:

1.- The removed tissue must be sent immediately to the Pathology Department so that it can be processed.

2.- Macro:

2.a. - The lymph node/s must be identified.
2.b. - We carry out cuts every 2mm and we include them all.
2.c. - Once sectioned, we carry out cytologic stamps.
2.d. - They are fixed in formol the following day.

3.- Intraoperatory:

In exceptional cases we express an intraoperatory diagnose with the cytologic stamps and the macroscopic aspect. Except for manifest positivity cases it is convenient to wait for the definitive study.

4.- Micro:

We carry out 5 micras sections to prepare 5 double preparations, one dyed with haematoxilin-eosin (HE) and the partner with Inmunohistochemistry (IH) with antikeratin antibodies (AE1-AE3), with sections 0.10mm the second and the rest every 0.20mm. The first two double preparations are dyed and assessed. If there is a positive result we proceed to write out the report and if it is negative, the rest of the preparations are dyed and after we give the corresponding result. If there were any problems or doubts the rest of the ganglionar tissue can be sectioned. The result is defined as positive or negative. In case of metastasic positivity with IH, the cellular group is assessed if it is than 10 cells ("occult tumoral colonies") in order to carry out posterior predictive studies.