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2003 Blackwell Publishing, Inc., 1075-122X/03/$15.00/0The Breast Journal, Volume 9, Number 6, 2003 509–510

Blackwell Publishing Ltd.

Biopsy of Sentinel Node in Mammary Cancer: Initial

Experience at the Centro Clinico de Estereotaxia, Caracas, Venezuela

To the Editor:The possibility of replacing axillary dissection with

biopsy of the sentinel node as the standard treatment inbreast cancer stages I and II with clinically negative axillais being thoroughly evaluated. The technique of lymphaticmapping and biopsy of the sentinel node has been broadlytested in patients with breast cancer (1,2). In most cases,the nodular status of the rest of the axilla is reflected bythe histologic characteristics of the node. This way, if wecan obtain a staging and an appropriate prognosticinformation with an accurate and less damaging proce-dure and as the biopsy of the sentinel node, the usefulnessof the axillary dissection will lesser in time (3). The pro-cedure will also enable the pathologist to focus on thehistologic evaluation of the sentinel node, potentiallyincreasing the reliability of the diagnosis (4).

The incidence of axillary metastasis in breast tumorssmaller than 2 cm has been reported by some authors to bearound 20% (5). In addition, certain factors of histologictype reduce the possibility of axillary node involvement.We present a prospective work that summarizes the experi-ence of the Centro Clinico de Estereotaxia (CECLINES),Caracas, Venezuela, in the biopsy of the sentinel node inpatients with breast cancer.

From February 1998 to August 2001, patients with ahistologic diagnosis of breast cancer with a tumor size of

≤

2 cm, determined by clinical examination, mammogra-phy, and ultrasound in the case of infiltrating tumors,and larger than 4 cm in cases of ductal carcinoma in situ(extensive ductal carcinoma) were included in the study.The clinical examination of the axilla did not show aden-opathies suspicious of metastasis. Patients with multiplelocal lesions, pregnant women, and male patients wereexcluded. In all the patients we conducted presurgicallymphatic mapping with identification of the axillary

sentinel node as the initial surgical procedure, followed bymastectomy, and later by the axillary dissection in thosecases in which the sentinel node was reported with malig-nant disease. To locate the node, a peritumoral injectionof dye was used: isosulfan blue or patent blue, with anaverage dose of 2.5 cc, 10 minutes before carrying out theaxillary incision.

In 51 cases (89.47%), the coloring injection was com-bined with a peritumoral injection of colloidal sulfide fromtechnetium 99 nonfiltered, with an average dose of 1

µ

Ci.During the intervention, a gamma radiation accountant(Europrobe, Eurorad, Strasbourg, France), without previouslymphoscintigraphy, was used. The injection of the radionu-clide (Tc99) was carried out 4–18 hours (average 12 hours)prior to the surgical procedure. The most radioactive pointwas located in the axilla and an incision of approximately3 cm was made in the line of insert of the axillary hair.

The dissection was carefully done by layers, using theradiation count as a guide, and visually, the blue dye of thelymphatic vessels, until the nodal structure was identified;thereafter the level of radioactivity of the node was deter-mined “in vivo,” and finally the node was excised. Theradioactivity count of the lymph node “ex vivo” was alwaysverified. Finally, we proceeded to a new exploration of theaxilla with the gamma counter to discard residual radio-activity and to rule out the presence of another sentinelnode. All our cases were evaluated by the same pathologistwith experience in breast pathology. When the sampleallowed, histologic cuts were done; furthermore, cytologywas used as support for the hematoxylin-eosin frozensectioning.

The surgical procedure was carried out only once, withan average stay at the hospital of 1 day. The last nineprocedures (15.78%) were carried out in an outpatientsetting. In 12 (21.05%) in which immediate mammaryreconstruction was used, the average of hospitalizationtime was 3 days. No intraoperatory complications wereregistered. A total of 57 cases were studied. The average

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age of the patients was 52 years (range 32–73 years). In thefirst 11 cases of our series we carried out axillary dissec-tion independent of the histologic results of the sentinelnode biopsy. There was only one identification failure. Wecarried out a total of 19 axillary dissections (33.33%), 3of them because the sentinel node could not be identified.Of the 16 remaining cases, in 8 cases (50%) the sentinelnode was negative and the rest of the dissected lymph nodesdid not show signs of disease. In the other eight cases(50%), the sentinel node proved positive for malignancy.Of these, in four (50%), disease was not demonstratedin the rest of the nodes of the axilla, and in four (50%),other positive axillary lymph nodes were reported. Nofalse negatives were reported.

The sensitivity of the method was 100%, with aspecificity of 100%. A success rate of 94.73% (54/57) inthe identification of the sentinel node was obtained. Theaverage time it took to identify the sentinel node was 18minutes (range 10–40 minutes). The average number ofidentified nodes was 1.35 (range 1–4 nodes).

In 48 of 54 cases (88.88%) the sentinel node wasreported negative for malignancy during surgery. Of these,five (10.41%) were reported with malignant disease inthe definitive histologic study: two cases (40%) had micro-metastases (infiltration

≤

2 mm). A total of 84.22% of thetumors measured less than 2 cm in the definitive histologicstudy. Of the 11 cases of sentinel node reported as posi-tive in the definitive histologic study, 7 (63.63%) corre-sponded to tumors 1–2 cm in size (T1c), 5 (45.45%) wereinfiltrating ductal carcinoma, 7 (63.63%) were moderatelydifferentiated, and 7 (63.63%) were nuclear grade III.

At the present time, intraoperative pathologic study ofthe sentinel node is the basis for a surgeon’s decisionmaking; nevertheless, we believe this must be reevaluated,since the decision should be taken with a definitive report,for which the recognizing procedure of the sentinel nodeshould be performed previous to the breast surgery.Diverse techniques have been described to optimize thediagnosis: cytology, frozen section, immunohistochemis-try, and others. Each node can be subjected to one or moreof these procedures, and the diagnostic certainty will berelated to the number, size, and other characteristics ofthe nodes. Likewise, the experience of the pathologist isfundamental (6). Moreover, the possibility of pathologicdiagnosis of one or more lymph nodes helps the surgeondecide whether to use axillary dissection or not, thusreducing the chances of a mistake. It should be pointed outthat in this series only 5 of 48 cases that were reported asnegative during the preoperatory stage (10.41%) showed

malignant disease in the final diagnosis. Of these, two(40%) were micrometastases, a fact that undoubtedlycontributes to the false negativity. We propose identifyingand extracting the sentinel node first to obtain an ade-quate histologic study, as well as determining differenttumor markers.

The present study shows that sentinel node analysisin our center produced favorable results similar to thosereported internationally, but long-term follow-up willbe necessary to determine the consequences concerningthe treatment and prognosis of every patient (7). Sentinelnode analysis is simple and useful for the diagnosis ofaxillary node disease and the consequent treatment ofbreast cancer in its early stages. The procedure can be per-formed in an outpatient setting. We pose the possibility ofperforming sentinel node analysis presurgically for betterdiagnostic accuracy and better surgical treatment of thepatient. The technique must be performed by personneltrained in the handling of mammary pathology.

Victor Acosta, MD Alberto Contreras, MD Ricardo Ravelo, MD Oscar Hurtado, MD Elena Marín, MD Aisa Manso, MD Jorge Pérez, MD Itala Longobardi, MDCentro Clinico de Estereotaxia, Caracas, Venezuela

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