Effect Of Needle Gauge On Adequacy and Accuracy Of Aspiration Biopsy In

Palpable Breast Masses

Joseph A. Estanislao, MD

Alexander D. Deveza, MD

Hazel Z. Turingan, MD

Maria Cecille T. Leyson, MD

Edgardo Penserga, MD, FPCS

Reynaldo O. Joson, MD, MHA, MHPEd, MS Surg

Department Of Surgery

Ospital Ng Maynila Medical Center

Malate, Manila

2002

ABSTRACT

Needle aspiration biopsy of palpable breast masses has varied techniques and outcome. The objective of this study is to see the effect of needle gauge (G) in the diagnostic adequacy and accuracy of this procedure. A randomized trial was done on 122 female patients with a palpable breast mass. Each patient was randomized to one of 3 arms, G-19 needle, G-21 needle, and G-23 needle. The use of G-19 needle had the best results in terms of adequacy of sample and conclusive reading compared to the use of G-21 and G-23. G-19 and G-21 had the same sensitivity, specificity and accuracy rates and these rates were higher than seen with the use of G-23 needle. With the results of this study, use of G-19 needle (1.5 inch long) is being recommended in the aspiration biopsy of the palpable breast masses.

Key words: needle aspiration biopsy, needle gauge, breast masses

INTRODUCTION:

Needle aspiration biopsy is presently and universally recommended ^1-3 as the initial diagnostic procedure in acquiring cytologic diagnosis of a breast mass because of its acceptable accuracy rae, safety, simplicity, and low cost. In the study by Kline et al.⁴, they reported an abnormal cell aspiration rate of 90% of 368 breast malignancies. Wilson and Ehrmann⁵ identified carcinoma in 92% of patients while Shabot et al⁶ had a 96% accuracy rate with aspiration cytology. Accuracy of this procedure has been reported to exceed 90%.^{3, 7}

Even with the widespread use of this procedure, there is still no known single protocol that is universally accepted. There are many variations in the technique of aspiration, size of needles and syringes used, number of needle passes, etc.^3,8-11 Studies had already been done by other authors regarding the other causes of variation but researches regarding the gauge of needles used have been very scarce. Because of this, the authors decided to study at least one of these variations.

The gauge of the needles used for needle aspiration biopsy in the literature has generally ranged from 18 to 25. ^{1-3, 8-9, 11-13} It is also the common practice in our hospital to use needle with gauge no larger than 21 in doing aspiration biopsy. But a high rate of inadequate smears (acellular and/or hemorrhagic smears) and inconclusive results (“atypical” reports) in the past reminded the authors that a larger bore needle is expected to yield more cells, thereby increasing the diagnostic yield and accuracy of the procedure. The issues of sampling adequacy, conclusive reports, and accuracy rate had been raised.¹⁴ Lazda et al ¹⁵ also reported percentages of breast aspiration samples reported as inadequate 46.8%, 20%, and 30.6% for years 1988-1989, 1991-1992, and 1993 respectively.

The general objective of this study is to determine the effect of needle gauge on the adequacy of samples and accuracy of aspiration biopsy of palpable breast masses.

The specific objective consisted ofa comparison of G-19, G-21, and G-23 needles in the aspiration biopsy of a palpable breast mass using the following parameters:

1. Sampling adequacy

2. Inconclusive report rate

3. Accuracy rate of interpretation

For the purpose of this study, the authors prefer the coinage “needle aspiration biopsy” to designate the procedure of aspirating a breast mass using 19-gauge or smaller gauge needle for cytologic evaluation. ⁸

The following histopathologic categories were likewise used in this study:

1) inadequate smear à no epithelial cells were identified. This category will include both acellular smears and hemorrhagic smears.

2) inconclusive results à adequate specimen but the pathologist was unable to make an interpretation of benign or malignant (this includes reports with “atypical cells seen.”

METHODOLOGY

A randomized double-blind study was done, where the patient did not know her group, and the pathologist did not know the gauge of needle used and the identity of the patient and to what group the patient belonged. In this study, as patients consulted they drew a stub which contained the group where they belonged. Independent personnel then took note of what group the patient belonged. Two senior residents performed all the needle biopsies.

Needle aspiration was used to evaluate 157 consecutive female patients with a palpable breast mass who consulted at Ospital ng Maynila Medical Center from July 2001 to December 2001. Excluded from the study were those with breast abscesses and cystic lesions.

Each patient was randomized to one of the 3 study groups upon consult:

1) GROUP A, the needle used was gauge 19 (1.5 inch long)

2) GROUP B, the needle used was gauge 21 (1.5 inch long); and

3) GROUP C, the needle used was gauge 23 (1.5 inch long).

The technique that was followed in the course of the study was the one published in the American Journal of Surgery. ⁹

The aspiration of each mass was done using the assigned needle attached to a 20-ml syringe. No local anesthesia was used as this may hinder the palpation and localization of the mass. A slightly oblique entry of the needle was made so as to avoid penetration into the chest wall. Ten milliliter of suction was applied, and a standard of 4 needle passes were made. Before removing needle from the mass, the syringe will be removed first to avoid cellular contents getting sucked into the syringe. Three smear-containing slides were then submitted to the pathologist for cytologic evaluation. After the results had come out the same mass will be excised, either as the sole procedure (excision only) or as part of a more definitive procedure (e.g. mastectomy). Cytology results of aspiration were compared with the final histopathological result of the specimen. Percentages of inadequate sampling and inconclusive report were computed. Likewise, sensitivity, specificity and accuracy rates were computed.

RESULTS:

One hundred fifty-seven female patients were included in the study. The age range was 12 to 79 years old with a mean of 35. Of the 157 patients, 5 had bilateral breast masses, which were sampled separately, bringing to 162 the total number of breast masses that were evaluated.

The 162 breast masses were equally randomized into the 3 groups, with 54 breast mass aspirations in each group.

The inadequate sampling rates were 0%, 17% and 18% for G-19, G-21, and G-23 respectively (Table 1).

The conclusive report rates were 96%, 78%, and 80% for G-19, -21, and G-23 respectively (Table 2).

The sensitivity, specificity, and accuracy rates for each gauge of needles are seen in Tables 3, 4, and 5.

The accuracy rates were 100%, 100%, and 97% for G-19, G-21, and G-23 respectively (Table 6).

No complications were noted in all the subjects.

The differences in sensitivity, and accuracy between the 3 groups were computed to be statistically significant, based on chi-square test (x²> 4.605). Likewise, the differences between the rate of inconclusive smears and those with conclusive smears based on needle sizes were determined to be statistically significant, based on chi-square test (x²> 4.605).

DISCUSSION:

The results of this study show that G-19 needle was the best compared to G-21 and G-23 needles in terms of sample adequacy, conclusive report rate, and accuracy rate. Based on this study, therefore, G-19 is being recommended as the gauge of needle to use in aspiration biopsy of palpable breast lumps.

The authors were not able to encounter research papers in the literature that deal compare G-19, G21, and G-23 needle gauge. However, there are some papers that compare other needle gauges. ^16,17 The results varied from no significant differences to a preference for bigger needle gauge.

Most of the papers are on fine needle aspiration biopsy which used needles with gauge 22 or smaller. The reason usually advanced by pathologists preferring the use of fine needles is the avoidance of a bloody smear. In this series, incidence of bloody smear with G-19 was lowest and even lower than that with G-21 and G-23. An explanation for this finding could either be that the fear of a bloody smear is just hypothetical or the sample size in this series was too small to account for the occurrence for a bloody smear with the G-19. Another hypothesis could be that a bloody smear may be dependent on the vascular status of the tumor and not on what gauge of needle is used.

From the results of this study, the acellularity and inconclusive rates were higher with smaller gauge needles. These findings are easy to understand on the basis of the volume of sample that a particular needle barrel can physically contain.¹⁷ The smaller the needle gauge, the higher the chance for acellularity and inadequate or fewer number of cells to be examined and interpreted by a pathologist. With acellularity and few number of cells, the higher the rate for inconclusive readings by the pathologist. A satisfactory number of cells is considered to contain 6 or more cell clusters in a paper which also stated that conclusive reading and accuracy rates could be affected by the amount of cells present in the smear¹⁸. The findings in this study are consistent with the hypothesis that the bigger the gauge, the more cells can be obtained for the smear. The more cells in the smear, the higher the conclusive report rate and the higher the accuracy rate. The other factor, however, that should not be forgotten that could influence the accuracy rate of an aspiration-biopsy report is the skill of the interpreting pathologist. This pathologist factor is most likely seen in the lower accuracy rate in the
G-23 group in this study, despite the smear being categorized as conclusive.

With the results of this study, our institution will now be using G-19 needle in the aspiration-biopsy of a palpable breast mass as part of its clinical practice guidelines and further validation of the effectiveness of this procedure will be done.

REFERENCES:

1. Reid, Cynthia. J Amer Coll Surg June 2000; 24: 11.

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5. Wilson SL, Ehrmann RL. The Cytologic Diagnosis of Breast Aspirations. Acta Cytol 1978; 22: 470-475.

6. Shabot MM, Goldberg IM, Schick PS et al. Aspiration cytology is superior to Tru-cut needle biopsy in establishing the diagnosis of clinically suspicious breast masses. Ann Surg 1982; 196: 122-126.

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12. Ballo MS, Sneig N. Can Core Biopsy Replace Fine-Needle Aspiration Cytology in the Diagnosis of Palpable Breast Carcinoma: A comparative study of 124 Women. Cancer 1996; 78: 773- 779.

13. Daltrey IR, Kissin MW. Randomized Clinical Trial on the Effect of Needle Gauge and Local Anesthetic on the Pain of Breast Fine-Needle Aspiration Cytology. Br J Surg 2000; 87: 777-779.

14. Smeets HJ, Saltzstein SL, Meurer WT, Pilch YH. Needle biopsies in breast cancer patients: Techniques in search of an audience. J Surg Oncol 1986; 32: 11-15.

15. Lazda EJ, Kocjan G, Sams VR, Witherspoon AC, Taylor I. Fine-Needle Aspiration Cytology of the breast: the influence of unsatisfactory samples on patient management. Cytopath 1996; 7: 262-267.

16. Daltrey IR, Lewis CE, McKee GT, Kissin MW. The effect of needle gauge and local anaesthetic on the diagnostic accuracy of breast fine-needle aspiration cytology. Eur J Surg Oncol 1999 Feb;25(1):30-3.

17. Helbich TH, Rudas M, Haitel A, Kohlberger PD, Thurnher M, Gnant M, Wunderbaldinger P, Wolf G, Mostbeck GH. Evaluation of needle size for breast biopsy: comparison of 14-, 16-, and 18-gauge biopsy needles. AJR Am J Roentgenol 1998 Jul;171(1):59-63.

18. Layfield LJ, Mooney EE, Glasgow B, Hirschowitz S, Coogan A. What constitutes an adequate smear in fine-needle aspiration cytology of the breast? Cancer 1997; 81(1):16-21.

Table 1. Comparison of adequacy of sample.

	G-19	G-21	G-23
Acellular smear	0	4	6
Hemorrhagic smear	0	5	4
Inadequacy rate	0% (0/54)	17% (9/54)	18% (10/54)

Table 2. Conclusive report rate.

	G-19	G-21	G-23
Inconclusive report	2	10	9
Conclusive report	52	35	35
Inconclusive rate	4% (2/54)	22% (10/45)	20% (9/44)
Conclusive rate	96%	78%	80%

Table 3. Results of conclusive report that used G-19 needle.

	BREAST CANCER		TOTAL
NEEDLE ASPIRATION BIOPSY	PRESENT	ABSENT
POSITIVE	19	0	19
NEGATIVE	0	33	33
TOTAL	19	33	52

Sensitivity = 19/19 x 100 = 100%

Specificity = 33/33 x 100 = 100%

Accuracy = 52/52 x100 = 100%

Table 4. Results of conclusive report that used G-21 needle.

	BREAST CANCER		TOTAL
NEEDLE ASPIRATION BIOPSY	PRESENT	ABSENT
POSITIVE	8	0	8
NEGATIVE	0	27	27
TOTAL	8	27	35

Sensitivity = 8/8 x 100 = 100%

Specificity = 27/27 x 100 = 100%

Accuracy = 35/35 x100 = 100%

Table 5. Results of conclusive report that used G-23 needle.

	BREAST CANCER		TOTAL
NEEDLE ASPIRATION BIOPSY	PRESENT	ABSENT
POSITIVE	1	0	1
NEGATIVE	1	33	34
TOTAL	2	33	35

Sensitivity = 1/2 x 100 = 50%

Specificity = 33/33 x 100 = 100%

Accuracy = 34/35 x100 = 97%

Table 6. Accurate report rate.

	G-19	G-21	G-23
Sensitivity rate	100%	100%	50%
Specificity rate	100%	100%	100%
Accuracy rate	100%	100%	97%