Other Guidelines

Quality control in the locoregional treatment of breast cancer

Lymphatic dissemination

Invasive cancer may lead to lymphatic dissemination. The most important primary tumour factors related to the risk of lymphatic dissemination are:

• Size of the tumour

• Grade

• Vascular invasion

Patients with micro-invasive (<2 mm) or tubular cancer up to 10 mm have a very low probability of lymph node metastasis. For these patients the search for lymph node metastasis or elective treatment of lymph nodes can be omitted [27] [28] [29].

The presence of lymph node metastasis is the most important prognostic factor for survival; the more involved the lymph nodes, the worse the prognosis [30]. Treatment of lymph node metastasis will result in a better lasting regional control of the disease [31]. Whether early treatment for clinically-occult lymph node metastasis has an impact on overall survival is not proven.

Indirect evidence strongly suggests a small, but significant, positive effect on survival [32] [33] [34].

In conclusion, the knowledge of lymph node dissemination will result in treatment adjustment to improve the outcome of the patient.

Measures to diagnose lymphatic dissemination are:

1. FNA cytology of clinically-overt enlarged regional lymph nodes
2. Ultrasound-directed FNA cytology of suspicious lymph nodes
3. Non-selective lymph node sampling
4. Axillary lymph node dissection (ALND), level I-II
5. Full axillary lymph node dissection, level I-II-III
6. Lymphatic mapping by the sentinel node (SN) procedure.

Every method has its own accuracy depending on experience, the a priori chance of lymph node involvement, the applied techniques. ALND (at least level I-II) resulting in the examination of at least 10 lymph nodes by the pathologists, has proven to give an excellent prognostic information on nodal status and axillary tumour control at the expense of certain morbidity, which is particularly a price to pay for node-negative patients [35]. If ALND is used as a staging procedure, it is recommended to perform a complete axillary clearance which results in sufficient axillary tumour control in the majority of node-positive patients [33][34]. Non-selective lymph node sampling may result in a sampling error, but has proven to provide sufficient prognostic information with less morbidity [36].

Maturing data from many prospective studies indicate that lymphatic mapping by the sentinel node technique may be an equal staging procedure compared with ALND [37] [38]. However, the sentinel node technique is laborious, demands expertise and a careful mapping of the sentinel nodes with tracers (lymphoscintigraphy, intraoperative use of the probe and dye). However, anyone involved in this new technique should be subject to a certain learning phase, including a training course and the verification of the procedure by an ALND in at least 25 and preferably 50 patients [39].

Once lymphatic dissemination to the axilla is established, it is generally accepted that treatment of the axilla is indicated [31] [32] [33] [34]. In clinically-overt disease, complete ALND (on indication followed by radiotherapy) provide the best axillary tumour control. If lymph node metastasis are found in the ALND specimen, in general the axilla is sufficiently treated except in extensive dissemination: arbitrarily more than four positive lymph nodes, a positive apical node, extra nodal growth are indications for adjuvant radiotherapy [32]. In these situations, the option of regional radiotherapy should be discussed with the patient. If, after non-selective lymph nodal sampling or after the sentinel node procedure, lymph node metastasis are found, there is a substantial risk that there are more tumour-positive nodes left behind in the axilla (after sentinel node procedures varying from 10 to 50%). These findings justify elective treatment of the axilla. The options for treatment of the axilla after lymph node sampling or sentinel node procedure are either complete ALND or radiation therapy of the axilla. What treatment leads to the best regional control with the least toxicity and long term morbidity remains to be established [34][40].

The elective treatment of internal mammary chain (IMC) nodes is heavily debated [41]. If lymphatic mapping locates sentinel nodes at the internal mammary chain, these nodes can be removed if they appear. If tumour-positive, the internal mammary chain area can be irradiated. When lymphoscintigraphy does not show drainage to the internal mammary chain, it is uncertain whether this implicates that there is a low risk of tumour dissemination to this region. The role of IMC node biopsy is currently under investigation.
The value of elective irradiation of the internal mammary chain nodes is currently investigated in a large European Organization for Research and Treatment of Cancer (EORTC) trial in patients with a positive axilla or medial located tumours.

OUTCOME MEASURE: For patients with invasive breast cancer of less than 2 mm or tubular cancer of less than 10 mm do not need lymphatic mapping or elective treatment of axillary lymph nodes.
OUTCOME MEASURE: For patients with an invasive cancer, information on the nodal status should have been obtained (lymph node sampling >4 nodes, ALND more than 10 nodes, sentinel node procedure).
OUTCOME MEASURE: More than 90% of the patients with invasive cancer and proven lymph node metastasis should have had axillary treatment (ALND, radiotherapy to the axilla or combined in extensive nodal involvement).

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