COMMENTARIES 783

SENTINEL NODE BIOPSY IN THE MANAGEMENT OF BREAST CANCER

Since Halsted introduced the radical mastectomy, there have beenonly a few major shifts in breast cancer surgery. These have beenbased on an emerging understanding of tumour biology and backedup by clinical trial evidence. The current major shift in axillary sur-gery, from full axillary dissection to lower level dissection and totargeted lymph node biopsy (sentinel node biopsy (SNB)) is high-lighted in this volume of the journal. Wilkinson

et al

. report on theearly experience from the Princess Alexandra Hospital in Brisbane,with 90% of sentinel nodes being identified with a combination oflymphoscintigraphy, intraoperative gamma probe localization andpatent blue dye but only 57% with blue dye alone.

1

In a similar paper from a single institution, Northshore hospitalin Auckland, Meyer-Rochow

et al

. report a ‘find rate’ for sentinellymph nodes of 90% when using patent blue dye only and 98%when using a combination of lymphoscintigraphy, gamma probeand blue dye together.

2

However, the contribution of lympho-scintigraphy to the success of finding the axillary sentinel node isdifficult to determine from the papers, except to say if an axillarynode is not seen on scintigraphy it might be more difficult tolocate with the other modalities.

Lymphoscintigraphy will sometimes identify an internal mam-mary or supraclavicular node presenting a management dilemma.Should these nodes be pursued surgically or should they be con-sidered in planning radiation fields without the knowledge oftheir pathological status? This is a particularly vexing question inregard to adjuvant therapy, when the sole drainage is medial andthe axillary nodes (if dissected) are clear.

False negative rates in small series are not informative as longas they are not excessive but large reviews have reported rates ofapproximately 5%.

3

Given there is a false negative rate at all, it isimperative that patients considering SNB be aware of this andthat standard axillary dissection also has a pathological false neg-ative rate. It would seem prudent that outside of a clinical trial,SNB be offered only to those patients with a low probability ofhaving positive axillary nodes and with their fully informed con-sent. Wilkinson

et al

. give a good profile of patients suitable forSNB and also give a method for calculating the ‘risk of increasedmortality’, which in the final analysis is what a patient wouldwish to know and to balance against less arm morbidity.

3

Although it is intuitive that SNB will produce much less armmorbidity, there are little data to prove this. Those surgeons con-tributing to the Australasian Sentinel Node or Axillary ClearanceTrial (SNAC) are encouraged to continue, as it is likely this willbe the last opportunity for a randomized trial of SNB and axillarydissection to prove both the efficacy of the procedure and assessits sequelae.

More detailed pathology examination of sentinel nodes,including immunohistochemistry has led to the identification ofnodal micrometastases. The question of what to do when micro-metastases are found in sentinel nodes remains unresolved andlarge studies are currently underway to clarify this managementproblem. It is clear from both papers in this issue that sentinelnodes containing obvious tumour are an indication to proceed to alevel II axillary dissection.

Finally there are a couple of practical hints offered: that peri-tumoural or pericavity injection seem to make little difference indetection rate; and that the acceptable time from isotopic injec-tion to surgery may be 2–22 h. Each surgeon and unit practisingSNB should develop and validate the technique in their ownenvironment and maintain an audit to benchmark against pub-lished data.

REFERENCES

1. Wilkinson DS, Wetzig NR, Bennett IC. Sentinel node biopsy forbreast cancer: using local results for estimation of risk to thepatient.

ANZ J. Surg.

2003;

73

: 811–14.2. Meyer-Rochow GY, Martin RCW, Harman CR. Sentinel node

biopsy in breast cancer: validation study and comparison of bluedye alone with triple modality localization.

ANZ J. Surg.

2003;

73

: 815–18.3. Hansen NM. Current status of sentinel node biopsy.

Seminars inBreast Disease

1998;

1

: 146–51.

S

TEWART

H

ART

, FRACS

Head of Breast ServiceMonash Medical CentreSouthern HealthVictoria, Australia

ANZ J. Surg.

2003;

73

: 783

COMMENTARY