A Review of the Use of Fine-Needle Aspiration Biopsy of Mammary Tumors for Diagnosis and Research

The accuracy of fine-needle aspiration (FNA) cytology in the diagnosis of breast lesions is based on the results of a study on 2,200 patients diagnosed between 1955 and 1962 [1]. To a large extent, this represented the work of the pioneer of FNA cytology, Dr. Sixten Franzén (1919-2008). From Figure 3 in this original article, it can be seen that relatively few patients, around 50 each year, were diagnosed between 1955 and 1959. After that, the number increased dramatically and reached over 900 in 1962. However, the early introduction of FNA in tumor diagnosis at Radiumhemmet, Karolinska Hospital, Stockholm, Sweden, took place in 1950 already, with the cases just not being registered properly before 1955.

The technique used for FNA biopsy was similar to that used in many institutions today, but the equipment was different, as can be seen from Figure 1. The one-handed-grip apparatus was used for aspiration by Sixten Franzén. The syringe was of glass and was nondisposable, which necessitated arduous cleaning by the technical staff. The 22-gauge needles were also nondisposable, and had to be cleaned after being used as well as being sharpened at regular intervals. Gloves were not used due to high costs.

The equipment used in the FNA cytology clinic may be outdated, but the diagnostic work is still first-rate. In 980 patients, the FNA cytologic diagnosis was not followed by surgery. In 764 of these patients, various benign lesions were diagnosed. The remaining 216 had inoperable carcinomas, thus representing 10% of all patients in the study. Today, inoperable carcinomas are rare in most developed countries as a result of many factors, such as screening mammography and high awareness among patients and doctors.

In 1,220 patients, the cytologic diagnosis was followed by surgery and histopathology. Benign histologic diagnoses were reported in 542 patients; in 96% of these, the cytologic diagnosis was benign. No false positive cytologic diagnosis was given.

A histopathologic diagnosis of cancer was reported in 645 patients. The FNA cytologic diagnosis was cancer or suspicious for cancer in 88.9%. In 9.1% of the cases, the cytologic material was nondiagnostic, reported as being due to unsatisfactory specimens. From the results presented, it can be seen that the percent of false-negative cytology decreased markedly with the increasing experience of the cytologist. This is an excellent example of a “learning curve.”

The excellent performance of FNA cytology in the diagnosis of breast lesions was confirmed in several simultaneous articles by Franzén and Zajicek [2,3,4]. This slowly led to the acceptance of FNA cytology as a valuable procedure in the diagnostic workup of patients with breast lesions.

Today, FNA cytology has been replaced by core-needle biopsy in some institutions. In the first instance, this can, to a large extent, be explained by the lack of interest shown by pathologists in obtaining the proper training in the FNA procedure and the interpretation of the cytologic smears. This reluctance inevitably results in low diagnostic accuracy and the abandonment of the FNA procedure. Secondly, a preoperative analysis of proliferation rate, hormone receptor content, and Her2 status is often required for the correct choice of therapy. Without proficiency in the FNA cytology procedure, this is difficult to achieve. There are, however, many institutions in which breast cytology is still the first approach in the diagnosis of breast lesions. In addition, aspirated cells offer an excellent material for the evaluation of biomarkers, with both immunocytochemistry and in situ hybridization [5,6].

The second part of the article describes the effect of negative pressure on cell viability during the aspiration procedure. This study was designed by Josef Zajicek (1923-1979), who, at the time, focused his research on using aspirated cells for the analysis of cellular enzymes as markers of malignancy and identifying the site of origin in metastatic cancer. In addition, the viability of aspirated cells as measured by dye exclusion after radiotherapy was studied to evaluate the effect of therapy. Figure 2 shows the elaborate apparatus for registering pressure differences during the biopsy procedure. In lymphocytes aspirated from a rat spleen, the viability was around 90% when the negative pressure was 80 mm Hg, as shown in Figure 5. From this figure, it can also be seen that a negative pressure of 760 mm Hg resulted in a decrease of viability, to approximately 75%. In contrast, cells aspirated from a series of 29 mammary carcinomas showed a much lower viability. Thus, in 50% of the cases, the viability was lower than 30%, as presented in Figure 6.

The use of aspirated cells for biological work continued for some years and resulted in several scientific reports. The cellular content of alkaline phosphatase was analyzed in cells aspirated from fibroadenomas and mammary carcinomas [7]. The enzyme level was 2-4 times higher in fibroadenomas than in carcinomas. In addition, the effect of radiotherapy on cell permeability was studied in cells aspirated from a metastatic squamous carcinoma and lymphoblastic lymphoma. Somewhat unexpectedly, the cells from the radioresistant squamous cell carcinoma increased their permeability. In contrast, the cells from the lymphoblastic lymphoma (which regressed completely after 11 days of radiation therapy) showed no increase in permeability.

Moreover, in a separate article, Esposti et al. [8] showed that cells aspirated from a prostatic carcinoma had lower levels of acid phosphatase than benign prostatic cells. The cellular content of acid phosphatase in cells from thyroid and mammary tumors was barely detectable, and it was suggested that this difference could be of value in the identification of metastatic prostatic carcinoma. In 1976, aspirated cells were used for measuring DNA synthesis by ³H-thymidine incorporation in patients treated with endocrine therapy for mammary carcinoma [9]. This produced promising results, but could not be introduced in routine work because of the laborious technique including autoradiography. After this, the interest in enzymatic reactions in aspirated cells diminished because the technique was difficult to reproduce, required microgram quantities of cells, and was time consuming.

The introduction of immunocytochemistry obliterated these problems since it was reproducible and analysis was possible from examimning less than 100 cells. This technique was established in the Karolinska Hospital Cytology Clinic early in 1980, to analyze hormone receptors, cell proliferation and clonality, and the subclassification of lymphomas [10,11,12,13]. These studies thus followed up Zajicek's intentions to give a preoperative biological characterization of tumors on FNA material.

However, let's go back to around 1970. The aspiration clinic attracted many patients and it was impossible for Sixten Franzén (an oncologist with no training in histopathology) to cope single-handedly with this task. So Torsten Löwhagen (trained in histopathology and an excellent teacher) was recruited and, together with Josef Zajicek (trained in histopathology and with a sharp intellect), they formed an ideal team. Franzén and Löwhagen were dedicated clinicians who examined the patients, performed the FNA biopsies, and read the slides. This concept, i.e., that a pathologist examines a referred patient, performs the FNA biopsy, and reads the slides, has been referred to as “the Karolinska Model”. Franzén had diagnosed and collected a large number of cases which Zajicek catalogued and compared to histopathology. Numerous scientific articles were published, several international courses given, and textbooks written on the subject. This work became the basis for the acceptance of FNA cytology in routine clinical work worldwide. These three men had different talents and personalities, but together they became the Titans of modern FNA cytology.

The authors have no conflicts of interest to declare.