Fine needle aspiration of the breast: review of the technique and a comparison with excisional biopsy

Summary Women presenting to a breast clinic with a palpable breast abnormality should be first examined by a clinician to establish a clinical diagnosis. If the nodule is believed to represent a cyst, needle aspirate and cyst drainage should be immediately performed. The cyst should be completely drained. Clear fluid may be discarded or preferably submitted for cytospin preparations and cytologic examination. Cloudy, turbid or bloody fluid requires preparation of direct smears and cytospins for cytologic examination. Any residual solid areas should be reaspirated and treated as any other solid nodule. When the palpated breast nodule is perceived as solid by the clinician, the patient should be sent for a mammogram either before an FNA is performed or 2 weeks after the FNA. This sequence avoids FNA artifact from distorting the mammographic appearance of the breast tissue and assures a satisfactory mammographic examination. Following the mammogram, the patient returns to the clinic where FNA of the nodule is performed, stained with the Diff-Quik method and diagnosed immediately without knowledge of the clinical or mammographic diagnoses but with adequate clinical history including: patient age, history of current pregnancy or lactation and information on prior breast disease. Patients with malignant clinical, mammographic and cytologic findings are informed of their diagnosis, therapeutic options are discussed and surgery or referral for a second opinion scheduled. Patients with benign triplet diagnoses who are deemed reliable are informed of the benign diagnosis, the need for close follow-up and a 3 month follow-up visit is scheduled. Patients, who the clinician believes may not return for follow-up clinic visits, are scheduled for open biopsy of the nodule. When discordant triplet diagnoses are obtained, the protocol is more complex but all patients with benign cytologic diagnoses but malignant clinical and or mammographic diagnoses are referred for open biopsy of the suspicious area. When the FNA discloses a malignancy, the patient is informed of the diagnosis, appropriately counselled and undergoes surgical therapy with a confirmatory frozen section prior to mastectomy. The widespread utilization of a diagnostic scheme as outlined in Figure 8 requires an understanding of the relative diagnostic accuracies of the biopsy techniques currently available, an informed and reliable patient population and a national health care and litigation policy recognizing the limitations of any and all diagnostic modalities. The accuracy of FNA cytology for the diagnosis of breast nodules is imperfect even in the most experienced of hands. The diagnostic accuracy of FNA is very similar to that of cutting needle biopsy and may even be superior to that of cutting needle biopsy. However, the false negative rate of FNA as an isolated technique (7%) is clearly higher than the 0.5%–1.4% associated with open biopsy. When FNA is used in the format of the Triple Diagnosis technique, its false negative rate is essentially identical to that of open biopsy. The major obstacles to generalized acceptance of FNA as the initial technique of choice for tissue diagnosis of breast nodules are represented by three issues. The first is the small but real reduction in diagnostic sensitivity of FNA in comparison to excisional biopsy. Second is the shortage of trained competent individuals capable of performing and interpreting FNA. Third is the resistance by the legal and medical communities to replace any successful and well established technique by a new method primarily on the basis of reduced cost and more rapid reporting turnaround time. This latter issue may indeed be the most critical obstacle to the wider use of FNA in the diagnosis of breast disease. Koss 44 brings the problem into focus when discussing malpractice issues and standard of care. Whenever a breast carcinoma is improperly diagnosed as benign by any technique other than excisional biopsy, that implies that the patient has not been treated within the ‘standard of care'. Such rationalizations indeed do reduce the utilization of FNA by many practitioners and hence, it may be perceived in a court of law as outside the standard of care. Only when national health care policy and the medical-legal environment change can FNA fully realize its potential. The degree of diagnostic sensitivity and the relative shortage of competent FNA practitioners are interrelated problems. Diagnostic sensitivity is maximized in the hands of appropriately trained individuals, competent in both the aspiration technique and the interpretation of FNA material. Most large university based pathology residency programs now require cytology as a rotation. Hence, most pathology residents receive training in FNA which should improve the supply of pathologists competent to interpret FNA smears. Despite this improvement, many aspirates continue to be performed by clinicians with little or no training in FNA technique. Most surgical and medical residencies do not offer realistic training in this method allowing the continuation of a perception that FNA is a simple technique requiring no skill. Until this belief changes, many FNA will still be inadequate and lead to falsely negative diagnoses. If FNA is to achieve its potential as the diagnostic technique of choice for the work-up of breast nodules, the supply of physicians competent in the technique must increase and national health care policy and the medical-legal environment must develop realistic expectations concerning the accuracy of any and all diagnostic techniques. As indicated by Koss, these changes will be needed before the advantages in cost and speed of diagnosis associated with FNA can be truly realized.