الفهرس 
ANATOMY OF THE BREASTOnly 14 pages are availabe for public view
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Abstract
I
n the last three decades, the management of breast cancer has changed dramatically. Gradually, the extent of breast surgery has evolved from radical mastectomy to modified radical mastectomy to more conservative approaches as lumpectomy followed by radiotherapy that is now known as breast conservative therapy.
Meanwhile, the same transformation is taking place in the management of the axilla in breast cancer patient, where the operations have evolved from complete ALND to a SLNB. One might refer to it as ”axillary conservation”. In this new era of SLNB, it has been shown to be highly accurate in determining when the remainder of the axilla is negative.
Many parameters have been demonstrated to predict prognosis in breast cancer, but multivariate analysis has shown that the most useful, independent factors are tumor grade, tumor size and lymph node metastasis. Of these, the most powerful is lymph node metastasis. Axillary lymph node status continues to be the single most important prognostic variable in patients with breast cancer. Thus, the evaluation of the axilla has been a major focus of interest in the treatment and staging of patients with breast cancer.
The sentinel lymph node is defined as any lymph node receiving lymphatic drainage directly from the primary tumour. Thus, it is the node most likely to be the site of initial lymphatic metastasis. The rationale is that, if the SLN is free from metastatic disease, the rest of the higher echelon lymph nodes in the axillary lymphatic drainage will also be negative and may therefore be left in situ.
SNB was started with peritumoral injection in the mid-nineties. Around the year 2000, many departments changed to subareolar injection, making SNB in nonpalpable breast lesions much easier. The simplicity and reliability of this method requires less expertise than other techniques. It avoids the necessity for image-guided injections for nonpalpable lesions. Moreover, subareolar injection reduces the shine-through effect from tumours located in the upper outer quadrant of the breast. It is also recommend that SLNB be considered in patients with multicentric at least in institutes with considerable experience in SLNB.
Intraoperative frozen sectioning with H&E staining in sentinel node is used as a single procedure. It had high sensitivity in detecting macrometastases but was not optimal in detecting micrometastases. Frozen section with IHC was somewhat superior to H&E in detecting micrometastases, but did not add anything to H&E concerning macrometastases. The combination of these two methods raised the sensitivity but still, only little more than half of the cases with micrometastases were found on intraoperative assessment. . Addition of IHC intra-operatively is not necessary since it only marginally increases overall accuracy at considerable expense. H&E.is a standard procedure that most pathology laboratories are familiar with, and is now recommended as intra-operative method in sentinel node biopsy for breast cancer.
Of patients with symptomatic breast cancer, 40% have positive nodes, compared with only 25% of patients with breast carcinoma detected by mammographic screening. As breast screening continues to expand, the proportion of lymph node stage 1 (node-negative) cancer will increase. Of symptomatic patients, 60% are potentially being over-treated by ALND; in screened patients, this rises to at least 75%.
Without any axillary treatment at all only 21% of breast cancer patients will develop axillary disease in their lifetime. Sentinel lymph node biopsy can not only select patients who would benefit from further axillary treatment, but, more importantly, select those who require no further axillary intervention.
In (1994) Giuliano and colleagues injected a 1% isosulphane blue solution in 174 patients and identified the SLN in 65.5% of the patients reporting a 93% success rate and 100% accuracy.
Albertini et al. in (1996) used vital blue dye solution and filtrated technetium-sulphur colloid to mark SLN. Out of 62 evaluated patients, SLN was identified in 57 (92%). Metastases were found in 18 SLN, which were all marked with the blue stain and radioactive colloid. There were no false – negative SLNs in this study.
Varghese, et al. in (2006) used methylene blue and combined dye and radioactive tracer to mark SLN. With blue dye technique alone SLN was identified in 96.5%. With the combined technique they found an improvement in the success rate to 98.7%. The false negative rate with both techniques was 3.7% - 4.1% respectively. Accuracy was 83.8% - 87.4% respectively. They concluded that combined technique facilitates quicker identification of sentinel lymph node; however the dye technique can be used successfully in centers without nuclear medicine facilities.
Several studies have shown the superiority of a combination of dye and radioisotope over dye alone in terms of the identification, significantly higher accuracy rate and false-negative rate. However the dye technique can be used successfully in centers without nuclear medicine facilities.
Tumor size, surgical procedure and tumor histology did not affect SLN identification. However, the level of success was markedly higher in patients without (79.0%) than in those with involved axillary lymph nodes (63.8%), as well as in those aged below 50 years (83.3%) compared with the patients over 50 years (64.8%). Also, experience of surgeons is very important for successful SLN detection. Giuliano, et al even think that there is a ”Learning Curve”, i.e. that the increase of SLN detection percentage correlates with the experience of the surgeons.
Sentinel lymph node biopsy in breast cancer can accurately stage the axilla; it is minimally invasive, safe and is an accurate procedure with less morbidity when compared to axillary clearance. Initially used in penile cancers and melanoma, it was applied to breast cancer using a radioisotope by Krag et al. in 1993. Sentinel lymph node localization using blue dye was used in breast cancer for the first time in 1994 by Giuliano using isosulfan blue.
Local complications after SLNB are rare. No injuries to motor nerves have been reported. Similarly, lymphoedema has not been reported so far. Skin tattooing from isofluran blue dye may occur, but the discoloration fades and becomes faint. Isosulfan blue and patent blue V dyes are particularly associated with allergic type of reactions. Methylene blue rarely evokes an allergic response. Occasionally; minor allergic reactions or even anaphylaxis has been reported with the dye technique. While systemic effects from the use of radiocolloid are rare.
Based on several reports, the success rate of SLN resection exceeds 90% and the overall accuracy exceeds 95%.The false-negative rate is defined as the number of negative SLNs identified within an axilla that is found to be positive on subsequent full examination of all the axillary nodes, divided by the total number of positive axillae. This varies greatly, between approximately 2% and 17%, but appears to be an average of approximately 5%. Most studies have demonstrated a learning curve for surgeons, during which the detection rate of SLNs increases to approximately 98% and the false-negative rate declines. The false-negative rate does not fall below 5%, and this seems to be accepted by the medical breast cancer community.
It has become clear that SLNB results in considerably less morbidity compared with ALND. Both lymphoedema (short- and long-term) and restriction of shoulder mobility are much less common in patients who undergo SLNB compared with ALND. In addition, the rates of wound infection are reduced, the duration of hospital stay is shorter, and patients can return to work more quickly following SLNB alone. This results in economic benefits for the health care system and society as a whole and improved quality of life for patients. The major advance in breast cancer treatment in the last decade has been the development of techniques that reduce the complications and extent of axillary procedure.