Ultrasound guided core biopsy for breast lesions using 16G needle

Abstracts

OBJECTIVE: The objective of this study was to develop a standard diagnostic evaluation with 16G core-needle biopsy for breast lesions. We evaluated the ideal number of fragments using standard ultrasound criteria based on the previous results obtained on the size of the lesions. MEHTODS: A prospective study was carried out, from may 2004 to September 2005, in 79 patients with lesions that included categories 2,3,4 and 5, according to BIRADS -USTM using 16G core biopsy needle. We took up 5 pieces numbered and placed individually in vials with 10% formalin. RESULTS: In 84 biopsies performed there were 81 conclusive diagnoses (96%), with 43 malignant results (51%) and 38 benign results (45%). The effectiveness of the core biopsy increased with the sample numbers: one sample is 95.24% accurate; two samples reach 96.93%; three samples reach 98.8%; four samples reach 98.81%, and finally, five samples reach 100% accuracy. CONLCUSION: the resection of three fragments was sufficient for a satisfactory result.

Breast neoplasms; Ultrasonography; mammary; Diagnostic techniques and procedures; Biopsy; needle

OBJETIVO: O objetivo deste estudo foi desenvolver um padrão de avaliação diagnóstica pela Core biopsy com agulha de 16G em lesões mamárias. Utilizando critérios ecográficos padronizados e relacionando os resultados ao tamanho das lesões investigadas e avaliando o número ideal de fragmentos a serem colhidos. MÉTODOS: Estudo prospectivo de maio de 2004 a setembro de 2005 em 79 pacientes com lesões incluídas nas categorias 2, 3, 4 e 5, segundo Bi-RADS® US, realizando Core Biopsy com agulha de 16G, retirando-se cinco fragmentos numerados e colocados individualmente em frascos com formol a 10%. RESULTADOS: De 84 biópsias realizadas houve 81 diagnósticos conclusivos (96%), com 43 malignos (51%) e 38 benignos (45%). A eficácia da Core biopsy aumenta com o número de amostras colhidas: com uma amostra é de 95,24%,duas amostras 96,93%; três amostras 98,8%; quatro amostras 98,81%; cinco amostras 100%. CONCLUSÃO: A retirada de três fragmentos foi suficiente para um resultado satisfatório.

Neoplasias da mama; Ultrasonografia mamária; Técnica de diagnóstico e procedimentos; Biópsia por agulha

ORIGINAL ARTICLES

Ultrasound guided core biopsy for breast lesions using 16G needle

Elizabeth Costa Martins^I; Alkindar Soares^II; Carlos Marques Guimarães^III; Maria de Nazaré Bastos da Serra Freire^IV; Hilton Koch^V; Martha Marsillac^VI

^IProfessor, Graduate Program in Gynecology, Santa Casa de Misericórdia do Rio de Janeiro, RJ, Brazil

^IIHead, Ward 28, Santa Casa de Misericórdia do Rio de Janeiro Gynecology Service, RJ, Brazil

^IIIEx-staff member, Ultrasonography Service, Ward 28, Santa Casa de Misericórdia do Rio de Janeiro, RJ, Brazil

^IVHead, Anatomic Pathology Laboratory, Ward 33, Santa Casa de Misericórdia do Rio de Janeiro, RJ, Brazil

^VFull Professor, Radiology, Universidade Federal do Rio de Janeiro (UFRJ), RJ, Brazil

^VIEx-staff member, Mastology Service, Ward 28, Santa Casa de Misericórdia do Rio de Janeiro, RJ, Brazil

Correspondence address

ABSTRACT

OBJETIVE: The objective of this study was to develop a standard diagnostic evaluation with 16G core-needle biopsy for breast lesions. We evaluated the ideal number of fragments using standard ultrasound criteria based on the previous results obtained on the size of the lesions.

METHOD: A prospective study was carried out, from may 2004 to September 2005, in 79 patients with lesions that included categories 2,3,4 and 5, according to BIRADS -USTM using 16G core biopsy needle. We took up 5 pieces numbered and placed individually in vials with 10% formalin.

RESULTS: In 84 biopsies performed there were 81 conclusive diagnoses (96%), with 43 malignant results (51%) and 38 benign results (45%). The effectiveness of the core biopsy increased with the sample numbers: one sample is 95.24% accurate; two samples reach 96.93%; three samples reach 98.8%; four samples reach 98.81%, and finally, five samples reach 100% accuracy.

CONCLUSION: The resection of three fragments was sufficient for a satisfactory result.

Key words: Breast neoplasms. Ultrasonography, mammary. Diagnostic techniques and procedures. Biopsy, needle.

INTRODUCTION

The high incidence of breast diseases, frequently malignant and with high mortality rates, necessitates more detailed studies for enhanced knowledge on the alterations presented by the mammary glands and the resulting improvement in propedeutics¹. This fact motivates us to be continuously developing new approach techniques to enable adequate diagnosis, especially when it comes to early diagnosis². The association of mammography with ultrasonography brought an important contribution to the diagnosis of breast disease³.

Ultrasound-guided core biopsy has been widely used in the histopathological study of mammary lesions, with a Positive Predictive Value (PPV) of 100% when compared with mammography (PPV 52.3%) in the diagnosis of those lesions⁴. Core biopsy is a crucial method to prevent unnecessary operations. Even when a surgical intervention is necessary, knowledge of the histopathological nature of the lesion enables more rational surgical planning and allows for greater efficacy in final outcomes⁵.

With respect to the prognosis for breast cancer patients, lesion size is the most determinant of all predictive factors, and the diagnosis of lesions smaller than 1 cm² is key to enhancing the survival of those patients⁶.

Most studies involving core biopsy use large-caliber 14-gauge (14G) needles that could hinder the collection of adequate material from smalls lesions, in addition to a greater risk for complications⁷.

Therefore, questions have been raised in more recent work regarding whether smaller caliber needles, such as 16G and 18G, could improve the diagnostic efficacy of core biopsy, particularly for lesions smaller than 1 cm², or whether providing smaller cores could hamper histopathological examination ⁸.

The aim of the present study was to develop a standard for diagnostic evaluation by core biopsy with a 16G needle on suspicious mammary lesions, using standardized sonographic criteria for the characterization and description of ultrasound images and relating the results to the size of the investigated lesions, as well as evaluating the ideal number of cores to be taken⁹.

METHODS

This study was approved by the Ethics Committee of the Institution where it was conducted and registered as CEP 009/05. Informed consent was obtained from the patients enrolled in the study or their relatives.

From May 2004 through September 2005, the study prospectively evaluated 79 patients with lesions included in categories 2 (benign), 3 (probably benign), 4 (suspicious) and 5 (highly suspicious) of the BI-RADS®-US classification. The study included all patients referred to our service on the basis of clinical suspicion, mammographic and sonographic studies, with a request for histopathological studies to be investigated through ultrasound-guided needle procedures. Patients who presented with cystic lesions or did not meet the above criteria were excluded from the study.

A sequential evaluation of the mammary lesions was performed through diagnostic imaging and invasive procedure, as follows:

A - After total mammary scan

A1 - The lesion was characterized sonographically according to standards from the Lexicon Classification Form - ACR BI-RADS® - US.

A2 - The volume of the lesion was estimated from three orthogonal measurements of diameters using the ellipse constant (0.52). For purposes of statistical calculations, the lesions were grouped according to size in smaller than 1 cm³, between 1 and 2 cm³, between 2.1 and 5 cm³ and larger than 5 cm³.

A3 - The lesion described on ultrasonography was classified according to the ACR BI-RADS® - US.

Ultrasonographic imaging was performed by a physician qualified by the American Board of Radiology. Ultrasonography was conducted on a Hitachi EUB 525 system (Hitachi Medical Systems) with a 7.5-10 MHz frequency spectrum probe and an L5 system (GE Medical Systems) with a 6.5-12MHz frequency spectrum probe.

B – Invasive approach

Prior to the procedure, the patient was advised to discontinue any type of medication that could affect coagulation.

B.1 – Local anesthesia was applied at the site of the procedure with a 1 mL injection of 2% xylocaine, intradermally, with no vasoconstrictor.

B.2 – The core biopsy was carried out with a 16G needle mounted onto an automated Pro-Mag 2.5 core biopsy gun (Manon Produtos Médicos, São Paulo, Brazil).

Five numbered cores were taken and placed individually in vials containing 10% formalin, also numbered .

C - Examination of the collected material

C.1 – The examination of the material was conducted by a physician with qualification equivalent to the American Board of Pathology certificate.

C.2 – The examination of the core biopsies was carried out sequentially, from the first to the fifth vial, providing individual histopathological results. At the end, the number of cores necessary for definitive diagnosis was determined.

The patients who, after biopsy, had clinical indication for surgical resection were operated on.

The anatomopathological examinations of the surgical specimens were performed by a second pathologist. The results obtained on the surgical specimen were compared with those from the first part of the evaluation.

The lesions with no indication for surgical excision were monitored at three-month intervals for one year in order to check for alterations in their dimensions and/or sonographic characteristics in relation to the initial examination.

The EpiInfo software was used for calculations of sensitivity, specificity, positive and negative predictive values for core biopsy overall and stratified according to nodule size.

To serve as criteria for calculations of sensitivity and specificity, as well as positive and negative predictive values, the lesions of patients on stable follow-up for over a year were considered to be benign lesions.

It must be noted that those lesions on follow-up had a cytological or histopathological benign diagnosis and were undergoing systematic reviews at three month intervals after initial diagnosis. All had already passed by the fourth review and all had proved stable.

Results of probably benign atypical hyperplasia were considered false-positive biopsies, as this result requires excisional biopsy for diagnostic confirmation, i.e., the patient is subjected to a theoretically unnecessary surgical procedure.

For the patients who underwent surgery, the surgical specimen was considered to be the gold standard.

RESULTS

Eighty-four biopsies were performed in 79 patients, since five patients had bilateral lesions, both biopsied. The mean age of the group was 49 ± 5 years (range, 15–90 years) and diagnosis was conclusive in 81 lesions (96%), 43 of them malignant (51%) and 38 benign (45%). There were two inconclusive results of cellular atypia (2%), subsequently confirmed with the diagnosis of benign lesion on the surgical specimen. One result of insatisfactory material occurred, for which new core biopsy was performed, with the diagnosis of malignant lesion confirmed on the surgical specimen. For purposes of statistical calculations, it was decided to maintain the result of the first biopsy.

Regarding the number of cores required for the diagnosis of the lesion, 80 out of the 84 biopsies were diagnosed with the first core; one required two cores; two lesions were diagnosed with three cores, none with a fourth core, and one case was diagnosed in the fifth core.

There was only one case of a small hematoma after punction, controlled by local compression after five minutes. Complete remission was verified after two weeks of sonographic monitoring.

DISCUSSION

When the methods of ultrasound-guided biopsy in general are evaluated and related to lesion size, cost/benefit considered, core biopsy is found to be the most sensitive method, as supported by the reported literature^10,11. It is the most widely used method for mammary lesion screening, since the sample is quite representative and has a low rate of inconclusive results. This helps prevent surgery in cases of benign lesions and enables individualized treatment for malignant lesions. It is important to emphasize the relevance of ultrasonography as an indispensable tool in this procedure, especially to identify and guide procedures on nonpalpable lesions. Ultrasonography associated with core biopsy enables the harvest of better quality material from small lesions.

There are a number of studies showing low sensitivity with only one sample^12,13. However, that can be enhanced with a greater number of core samples taken¹⁴. In our study, core biopsy accuracy with three samples taken was 98.81%. The use of the 16G needle yielded the same satisfactory results when compared with similar studies using 14G needles^14,15. The 16G caliber permits better transit through the mammary tissue, especially for breasts in which glandular tissue predominates, and eliminates the need for a skin incision with a scalpel for needle entry. It also provides cores with viable sizes for histopathological analysis.

It is worth noting the good performance of core biopsy in the present study with a 16G needle for lesions smaller than 1 cm³. Most of our study cases were tumors smaller than 1 cm³ (27%), and in 20 cases (24%) tumors were between 1 and 2 cm³. Table 1 correlates the classification of lesions after core diagnosis with their respective volumes. Even with small tumors, the diagnosis based on core biopsy achieved 100% sensitivity and high specificity – ranging from 80% to 90%. Table 2 shows the sensitivity, specificity, positive and negative predictive values of the core biopsy and table 3 relates core biopsy sensitivity, specificity and positive and negative predictive values to nodule size.

In the group of suspicious mammary lesions, the use of a 16G needle for core biopsy revealed high sensitivity and specificity, as well as a high percentage of usable material. Collecting three cores is sufficient for a satisfactory result and affords safety in the diagnostic management of those patients.

REFERENCES

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Publication Dates

• Publication in this collection
  09 Nov 2009
• Date of issue
  Aug 2009

History

• Received
  04 Nov 2008
• Accepted
  15 Jan 2009