Aspiration Needle Biopsy of Thoracic Lesions

Transcription

1 Aspiration Needle Biopsy of Thoracic Lesions T. R. J. Todd, F.R.C.S.(C), G. Weisbrod, F.R.C.P.(C), L. C. Tao, F.R.C.P.(C), D. E. Sanders, F.R.C.P.(C), N. C. Delarue, F.R.C.S.(C), D. W. Chamberlain, F.R.C.P.(C), R. Ilves, F.R.C.S.(C), F. G. Pearson, F.R.C.S.(C), W. Cass, F.R.C.P.(C), and J. D. Cooper, F.R.C.S.(C) ABSTRACT We reviewed our experience with 2,114 percutaneous aspiration needle biopsies of intrathoracic lesions. Aspiration was performed for cytological diagnosis employing biplane fluoroscopy and a 20 gauge needle, 0.9 mm in outside diameter. A satisfactory specimen was obtained in 88% of biopsies, and the chance of obtaining a correct diagnosis of a malignant lesion was 81.5%. The false positive rate was 2.2%, and the cytologists could always distinguish between primary and secondary neoplasms. A false negative rate of 13.6% (36 patients) resulted in only three delayed thoracotomies and two instances of interval metastases discovered at mediastinoscopy. Cellular specificity in primary tumors was not sufficiently accurate to affect therapy. Pneumothoraces occurred frequently (31.9% of patients) but were generally small; of patients required chest drainage. There were no recorded instances of tumor implantation in needle tracts. We conclude that a rapid and accurate diagnosis of intrathoracic pathology can be obtained by this technique. It is associated with an acceptable morbidity and may greatly expedite both patient care and investigation. Aspiration needle biopsy of intrathoracic lesions has become increasingly popular in North America during the last 10 years. However, controversy concerning its value in clinical practice and concern about the variously reported complications remain. An initial report from our institution in 1971 concluded that From the Division of Thoracic Surgery, and Departments of Pathology and Radiology, Toronto General Hospital, Toronto, Ont, Canada. We are grateful to Mrs. Joan Basiuk and Mr. Robert Fehr for supervising the acquisition of data and the management of our computer facility. Presented at the Seventeenth Annual Meeting of The Soaety of Thoracic Surgeons, Jan 26-28,1981, Los Angeles, CA. Address reprint reauests to Dr. Todd, Division of Thoracic Surgery, Eaton 10-i28, Toronto General Hospital, Toronto, Ont, Canada M5G 1L7. there was very little morbidity and no mortality in a series of 182 biopsies ill. A correct diagnosis was achieved in 75% of patients in that series. Encouraged by those results, aspiration biopsy became increasingly utilized as a diagnostic tool in our institution and has been employed extensively to streamline patient investigation and to reduce the number of lesions that were being observed. Since the complication rate appeared low [ll, the indications were extended to patients with advanced obstructive airway disease and to lesions that because of their size or location appeared difficult to aspirate. Most reported experience with this technique has been entirely retrospective and, with few exceptions L2-41, consists of relatively small numbers. As a result we have conducted both a retrospective survey as well as a prospective study of percutaneous aspiration transthoracic biopsy. This series represents the results of a broad application of aspiration biopsy over the past 13 years. Our current contraindications include coagulopathies, severe bullous lung disease in patients with respiratory impairment, and suspected vascular or hydatid lesions. Material and Methods Patient Population RETROSPECTNE SERIES. The charts of 1,442 patients who underwent 1,659 biopsies were reviewed thoroughly. Data were collected on checklist forms and stored in a computer facility for eventual processing. All false negative and false positive biopsies were reviewed a second time by one of us (T. R. J. T.) to be certain of the accuracy of the initial review. Detailed follow-up forms were developed and sent to the physicians of all patients who did not undergo operation to further assess the accuracy of the biopsy. Replies were received for 1,084 patients by The Society of Thoracic Surgeons

2 155 Todd et al: Aspiration Needle Biopsy PROSPECTIVE SERIES. Similar data were accumulated in a prospective fashion for 398 patients who underwent 455 biopsies during the last 2 years of the study. Each cytological biopsy was evaluated by one of two cytopathologists, and chest roentgenograms (inspiration and expiration) were reviewed by the radiologist performing the procedure at 4 and 24 hours following the biopsy. As in the retrospective analysis, follow-up forms were completed by the referring physicians on medical patients. Six months of follow-up were required in this group prior to assessment. There were a total of 306 biopsies on outpatients. Follow-up roentgenograms were not performed at 24 hours in this group unless a pneumothorax had been documented on the 4-hour roentgenogram. Technique of Aspiration Biopsy All biopsies were done employing a modification of the procedure described by Dalgreen and Nordenstrom [51. The location of the lesion is determined fluoroscopically. Then a 20 gauge needle, 0.9 mm in outside diameter and measuring 12.7 or 7.6 cm in length, is inserted with the stylet in place. The position of the needle in the lesion is verified by biplane fluoroscopy and by the resistance and texture of the lesion, movement of the lesion with movement of the needle, or movement of both needle and lesion in concert during normal respiration. With the stylet still in place, the needle is rotated both clockwise and counterclockwise to loosen a small amount of tissue. The stylet is removed while the patient holds his breath, and strong suction is applied with a 50 ml syringe. Any material obtained is assessed cytologically and also sent for all appropriate bacteriological and fungal cultures as well as immediate gram and acid-fast stain. If no material is obtained in the syringe (the usual situation), any material or fluid in the needle is expressed onto a frosted glass slide with the syringe. The slide is dipped in 95% alcohol just prior to preparation of the specimen. After the aspirated material is placed on the slide, it is fixed with cytospray." In addition, any material in *ICN Canada Ltd., Montreal, Que, Canada. the barrel of the syringe or on the plunger is similarly smeared on glass slides. The needle and syringe are then rinsed with mucolex solution, and the washings are submitted for further cytological evaluation. Diagnostic Classification The vast majority of biopsies were done to determine the possible malignant nature of the radiological abnormality. In every instance, the cytologist tried to apply strict criteria to his assessment, and the following diagnostic categories were developed for the purposes of this report. Malignant. A malignant diagnosis included all specimens with cytological features either definite for or highly suggestive of malignancy. In most instances, attempts were made to determine the cell type in primary tumors and the tissue of origin for secondary malignancies. Benign. A diagnosis of benign tumor or nonneoplastic process required definite cytological evidence of abnormal cells possessing no malignant characteristics. Unsatisfactory. This category included those biopsies for which material was scant or poorly prepared, and those for which only normal cellular elements of the lung were identified. Such biopsies were considered unsatisfactory because a biopsy of the lesion itself had probably not been obtained. Results Statistical evaluation of both the retrospective and prospective series revealed differences in the two studies in but a few areas. As a result, the two studies were combined for simplicity of presentation. Significant differences are indicated. A total of 2,114 biopsies were obtained. By cytological diagnosis, 1,086 (51.4 %) of these were malignant, 974 primary and 112 secondary; 464 (21.9%) were benign; 466 (22%) were unsatisfactory; and 98 (4.6%) had no available report. With an overall unsatisfactory rate of 22%, a definite cytological diagnosis was made in 78% of biopsies. In the prospective study, the unsatisfactory rate dropped to 14%. Almost

3 156 The Annals of Thoracic Surgery Vol 32 No 2 August 1981 Table 1. Eventual Pathological and Cytological Finding in 420 Primary Malignancies Cytological Accuracy (%) Cytological Pathological Malignancy Finding Finding Overall Prospective Squamous cell 159 Adenocarcinoma 60 Oat cell 16 Large cell 106 Bronchiolar 22 Unspecified 57 or mixed No. with False Follow-up No. Negative Study Total (6 mo) Malignant Rate (YO) Combined study Tumors Inflammationsa Prospective study All the false negatives were in the group with inflammatory diagnoses. half of the lesions biopsied in the prospective study were hilar (14y0), extraparenchymal (9%), or, if peripheral, less than 2 cm in greatest diameter (22%). Malignant Lesions The diagnosis of malignancy was confirmed by tissue histology in the resected tumors. In the nonresected tumors, malignancy was assumed on the basis of evidence of malignant progression on follow-up. At least six months of follow-up was obtained before confirmation was accepted. In the combined study, 81.5% of all eventually proved malignancies were correctly diagnosed cytologically at aspiration biopsy (84.6% in the prospective study). The accuracy of malignant cytological diagnosis was as follows: Out of 778 lesions labeled malignant by the cytologist and available for confirmation (histology or follow-up), 761 (97.8%) were confirmed as malignant. The false positive rate was 2.2%. Table 1 demonstrates the frequency of agreement between cytologist and pathologist in the cell typing of primary tumors for those patients for whom tissue histology is available for comparison (n = 420). There were 112 secondary neoplasms. In every instance, the cytologist was able to differentiate primary from secondary malignancies. The exact tissue of origin was specified by the cytologist in 64 of the 112 biopsies (57%). In 27, tissue was available for comparison. The cytologist was proved correct in 22 of the latter. Benign Lesions In patients with benign lesions, the accuracy of cytological diagnosis was evaluated when there was available tissue pathology or adequate clinical follow-up for confirmation. Out of 295 biopsies, 36 were found to be malignant. The false negative rate for the overall study was 12.2%. This rate fell to 8.6% in the prospective study. Of 41 lesions diagnosed as benign neoplasm by aspiration biopsy, follow-up was available on 30 and all 30 were confirmed benign (Table 2). Eleven of these underwent thoracotomy in our own institution, and hence we had pathological studies available for comparison. In each case, the cytologist correctly identified the specific tumor. There were 423 biopsies reported as inflammatory processes either specific (158) or nonspecific (265). Most

4 157 Todd et al: Aspiration Needle Biopsy of the 158 specific inflammations were tuberculosis but Cryptococcus, coccidioidomycosis, aspergillosis, and Chlamydia were seen. Among the 265 nonspecific inflammatory lesions at aspiration biopsy, 36 malignancies (13.6%) were discovered at follow-up. This accounted for all the false negative biopsies in the series. Eighteen of the 36 patients eventually underwent thoracotomy and resection (15 immediately and 3 delayed) because carcinoma was suspected on clinical grounds. Fourteen of these patients with false negative results were considered medically or surgically inoperable at the time of the biopsy and further efforts for tissue diagnosis were abandoned. Of the remaining 4 patients, 2 were found to have interval metastases at a subsequent mediastinoscopy and full information on the final 2 patients is not available. Unsatisfactory Diagnoses In the combined study, 22% of aspirates failed to yield a cytological diagnosis of definite disease involvement. The incidence of unsatisfactory specimens in the prospective study was 14 9'0 and is representative of current effectiveness. There were 196 patients who underwent a second biopsy attempt because the initial specimen was unsatisfactory. In 157 of them (8O%), a satisfactory specimen for diagnosis was obtained (67, benign; 90, malignant). Success by Size, Location, and Radiographic Appearance There were 177 lesions definitely known to be less than 2 cm in greatest diameter. Satisfactory specimens for a specific diagnosis were obtained in 134 (75.7%) of these small lesions. Only the prospective study had adequate radiographic information allowing for delineation between hilar and peripheral lesions. Satisfactory specimens were obtained more frequently from peripheral lesions (86%) than from hilar lesions (73%). There were a number of radiological abnormalities that could not be labeled as nodules or masses or even parenchymal disease. The success of aspiration needle biopsy with these abnormalities was as follows: atelectasis or consolidation or both, 68 instances and an accuracy of 63%; extraparenchymal disease, 51 and an accuracy of 78%; and interstitial disease, 12 and an accuracy of 75%. Complications There were no deaths associated with this procedure. There were no reported instances of hemothorax, air embolism, or tumor implantation in needle tracts. Pneumothoraces were recorded in 31.9% of patients undergoing aspiration biopsy. The majority of these were small and insignificant, and only 10.4% of patients in the total series required tube thoracostomy. Pneumothorax occurred with equal frequency in inpatients and outpatients, and there was no difference in incidence between biopsies done by staff physicians and those done by residents. Hemoptysis is rare. Any increase in the size of the lesion noted on roentgenograms made after aspiration was considered to represent hemorrhage. The overall rate of hemoptysis and hemorrhage was 1.4%. Comment Numerous reports have documented the success and diagnostic accuracy of aspiration lung biopsy [ Our success rate of 81 to 84% in malignant lesions compares favorably with that documented from other centers. In fact, most studies report success rates of 78 to 90% in malignant lesions. The variability is likely due to patient selection. Of particular note in our study was the consistent ability of the cytologist to distinguish between primary and secondary malignancies and to confirm the exact tissue of origin in 46% of the metastatic lesions. The cytologist reviewing the needle biopsy and the pathologist assessing available histological data concurred in the cell type in 70% or more of proved squamous cell and adenocarcinomas (see Table 1). The correlation between cytological and subsequent pathological findings was less consistent for other cell types. Indeed, in patients with oat cell carcinoma, the diagnosis correlated in only 37.5%. Baker [12] agrees with our reservations about accepting the cytological diagnosis of oat cell carcinoma. In the absence of mediastinal or distant metastases, we do not consider an aspiration biopsy diagnosis of oat cell carcinoma a contraindication to resection.

5 158 The Annals of Thoracic Surgery Vol 32 No 2 August 1981 Others [15, 171 report similar comparisons between cytological and pathological findings. False negative rates reported in the literature are quite consistent [7, 13, 151, although some higher rates [lo, 141 emphasize the need for sound clinical judgment in deciding whether a nonmalignant aspirate is truly representative. A diagnosis of a benign neoplasm appears to allow for greater confidence (see Table 2). The acceptance of other nonspecific benign diagnoses warrants consideration of the patient s age, operative risk, clinical history, and the radiographic appearance of the lesion. All 36 patients with false negative biopsies in this series were given a cytological diagnosis of nonspecific inflammation. As a result of clinical judgment, 18 of these patients underwent thoracotomy; in only 3 was operation delayed for longer than four months. Complete information is available on 16 of the remaining 18 patients. Fourteen were considered either medically or surgically inoperable at the time of needle aspiration biopsy. The remaining 2 underwent close follow-up but at the time of the subsequent assessment were found to have mediastinal metastases. In more than 1,000 patients with malignancies biopsied in this series, only 5 had delayed surgical management. In 2 of them, interval metastases may have developed. The value of aspiration biopsy lies in the rapid diagnosis of undiagnosed pulmonary lesions because 84% of malignancies will be identified promptly. The effect on the efficiency of patient investigation and resultant costeffectiveness is difficult to evaluate. However it is apparent in our own practice that the speed and simplification of preoperative investigation are enhanced. In the majority of patients, a report is available within 6 to 24 hours, and, if malignancy is identified, the need for further diagnostic investigations is obviated. An established preoperative diagnosis avoids intraoperative diagnostic maneuvers prior to definitive resection. It allows the surgeon to fully inform the patient about the nature of the disease and about the nature of the anticipated surgical procedure. In addition, a diagnosis is readily accessible in instances of medical or surgical inoperability. Finally, a more precise 2ol 10 Overall (398) 0 Squamous (253) A Adeno (52) I I I I I Actual 5-year survival among 398 consecutive patients with bronchogenic carcinoma who underwent resections performed by one of us (N. C. DJ. selection of patients to be observed can be made and management decisions undertaken with greater confidence. In this series, only 5 patients with intrathoracic malignant neoplasms underwent observation before definitive therapy. The value of any technique must be considered in relation to its complications. We noted no instance of tumor implantation in our series. A review of the literature revealed only one instance of implantation metastases following aspiration biopsy [18, 191. Other reported implantations occurred with the use of Vim- Silverman needles [ The risk of systemic dissemination is probably more theoretical than real, as evidenced by our expected survival curves in the Figure and those reported by others in patients undergoing aspiration biopsy [2]. Most of the patients included in the Figure underwent aspiration needle biopsy. Tumor cells frequently are found in the blood of patients even without such procedures [23, 241 and do not appear to affect the prognosis (251. Finally, Engzell [26], in both animal experiments and in a clinical series of 626 patients, investigated the possibility of spread due to needle biopsy and found no evidence to support this contention.

6 159 Todd et al: Aspiration Needle Biopsy A review of the literature indicates that there have been 9 deaths following aspiration needle biopsy of lung [3, 10, 16, 27-32]. These deaths were attributed to cardiac arrest (3), air embolism (2), pneumothorax (l), and hemorrhage (3). We recorded no deaths in 2,114 biopsies, and it is interesting to note that all but 2 of the deaths reported in the literature occurred prior to Pneumothoraces occurred frequently in our series and in many others [2,3,7, 10,12,16,17, 33, 341. Most pneumothoraces are small and apical, and their rate is high if the radiologist closely scrutinizes the roentgenograms of each patient. Chest roentgenograms, on both inspiration and expiration, were obtained 4 and 24 hours after each inpatient biopsy in our series and specifically were reviewed by the physician performing the biopsy. Chest tubes were required in 10.4% of patients in the present series. In our literature review of approximately 12,000 patients only 1 death was attributed to a pneumothorax definitely. As our indications for biopsy were extended, the rate of pneumothorax increased despite the use of the same technique and the presence of the same radiologists. From 1965 to 1970, the rate of pneumothoraces was 16% and chest tubes were required in 5.8%. From 1970 to 1975, the rate was 24% and chest tubes were needed in 8.2%. From 1975 to 1981, the rate was 36% and chest tubes were required in 11.4%. It is likely that the rate of pneumothoraces can be reduced by the use of small needles [9, 35-37] and the introduction of clot through the needle at the conclusion of the procedure [ll, 35, 381. In summary, we believe that percutaneous aspiration needle biopsy is a worthwhile adjunct in the investigation of intrathoracic disease involvement. It provides accurate information that may influence patient management. The concern that a negative aspiration biopsy may be incorrect and misleading will be overcome if nonmalignant aspirates are assessed in the light of the clinical situation. As a result, a nonspecific nonmalignant aspiration biopsy does not influence our subsequent management of the patient with an undiagnosed pulmonary nodule. The morbidity with percutaneous aspiration needle biopsy is accept- able, and mortalities in the larger series are rare. Improvement in the success rate of aspiration can be anticipated with experience. Accurate cytological diagnosis requires the assistance of an expert cytopathologist, and we recognize that such expertise is not available in many institutions. References 1. Sanders DE, Thompson BW, Budden BJE: Percutaneous aspiration lung biopsy. Can Med Assoc J 104:139, Sinner WN: Complications of percutaneous transthoracic needle aspiration biopsy. Acta Radiol [Diagn] (Stockh) , Lalli AF, McCormack LJ, Zelch M, et al: Aspiration biopsies of chest lesions. Radiology 127:35, Sage1 SS, Ferguson TB, Forrest JV, et al: Percutaneous transthoracic aspiration needle bi-, opsy. Ann Thorac Surg 26:399, Dahlgreen S, Nordenstrom B: Transthoracic needle biopsy. Chicago, Year Book, Kline TS, Hunter HS: Needle aspiration biopsy: a critical appraisal. JAMA 239:38, Landman S, Burgener FA, Lim GHK: Comparison of bronchial brushing to percutaneous needle aspiration biopsy in the diagnosis of malignant lung lesions. Radiology 115:257, Herman PG, Hessel SJ: The diagnostic accuracy and complication of closed lung biopsies. Radiology 125:11, Chin WS, Yee IST: Percutaneous aspiration biopsy of malignant lung lesions using the Chiba needle: an initial experience. Clin Radiol 29:617, Francis D: Aspiration biopsies from diagnostically difficult pulmonary lesions. Acta Pathol Microbiol Scand [A] 85:235, Bierny JP: Lung needle biopsy. Ariz Med 36:433, Baker RR: The role of percutaneous needle biopsy in the management of patients with peripheral pulmonary nodules. J Thorac Cardiovasc Surg 79:161, Zelch JV, Lalli AF, McCormack LJ, Belovich DM: Aspiration biopsy in diagnosis of pulmonary nodule. Chest 63:149, Hajdu SI, Malamed MR: The diagnostic value of aspiration smears. Am J Clin Pathol 59:350, Hayata Y, Kenkichi 0, Ichiba M, et al: Percutaneous pulmonary puncture for cytological diagnosis: its diagnostic value for small peripheral pulmonary carcinoma. Acta Cytol (Baltimore) 17:469, Sargent EN, Turner AF, Gordonson J, et al: Percutaneous pulmonary needle biopsy: report of

7 160 The Annals of Thoracic Surgery Vol 32 No 2 August patients. Am J Roentgenol Radium Ther Nucl Med 122:758, Meyer JE, Gaudbhu LH, Milner LB, McLaughlin MM: Percutaneous aspiration biopsy of nodular lung lesions. J Thorac Cardiovasc Surg 73:787, Sinner WN: Transthoracic needle biopsy of small peripheral malignant lung lesions. Invest Radiol 8:305, Sinner WN, Zajicek J: Implantation metastases after percutaneous transthoracic needle aspiration biopsy. Acta Radiol [Diagn] (Stockh) 17:473, Dutra FR, Geraci CL: Needle biopsy of the lung. JAMA 155:21, Wolinsky H, Lischner MW: Needle tract implantation of tumour after percutaneous lung biopsy. Ann Intern Med 71:359, Berger RL, Dargan EL, Huang BL: Dissemination of cancer cells by needle biopsy of lung. J Thorac Cardiovasc Surg 63:430, Roberts S, Jonasson 0, Long L, et al: Relationship of cancer cells in the circulating blood to operation. Cancer 15:232, Sandberg AA, Moore GE, Schuberg JR: Atypical cells in the blood of cancer patients: differentiation from tumour cells. J Nat Cancer Inst 22:555, Engell HC: Cancer cells in the circulating blood. Acta Chir Scand [Suppl] 201, Engzell U: Investigation on tumour spread in connection with aspiration biopsy. Acta Radiol [Ther] (Stockh) 10:385, Meyer JE, Ferrucci JT Jr, Janower ML: Fatal complication of percutaneous lung biopsy. Radiology 96:47, Lauby JW, Burnett WE, Rosemond GP, Tyson RR: Value and risk of pulmonary lesions by needle aspiration: twenty-one years experience. J Thorac Cardiovasc Surg 49:159, Milner LB, Ryan K, Gillio J: Fatal intrathoracic hemorrhage after percutaneous aspiration lung biopsy. Am J Roentgenol 132:280, Westcott JL: Air embolism complicating percutaneous needle biopsy of lung. Chest 63:108, Pearce JG, Patt NL: Fatal pulmonary hemorrhage after percutaneous aspiration lung biopsy. Am Rev Respir Dis 110:346, Woolf CR: Applications of aspiration lung biopsy with a review of the literature. Dis Chest 25:286, Castelleno RA, Blank N: Etiological diagnosis of focal pulmonary infection in immunocompromised patients by fluoroscopically guided percutaneous needle aspiration. Radiology 132:563, Kjeldgaard JM: Percutaneous transthoracic needle biopsy. J Maine Med Assoc 70:383, Ballard GL, Boyd WR: A specially designed cutting aspiration needle for lung biopsy. Am J Roentgenol , Zornoza J, Snow J, Lukeman JM, Libshitz HI: Aspiration biopsy of discrete pulmonary lesions using a new thin needle. Radiology 123:519, Pinsker KL, Kamholz SL, Johnson J, Schreiber K: Fine needle aspiration biopsy of intrathoracic lesions. Chest 78:3, McCartney R, Tait D, Stilson M, Seidel GF: A technique for the prevention of pneumothorax in pulmonary aspiration biopsy. Am J Roentgenol Radium Ther Nucl Med 120:872, 1974 Editor s Note Needle aspiration of pulmonary lesions has become an important part of the thoracic surgeon s diagnostic armamentarium. The report emphasizes its value. It is important, however, to recognize the limitations of the technique in the cytological diagnosis of oat cell carcinoma. Discussion DR. THOMAS B. FERGUSON (St. Louis, MO): I was asked to discuss this paper by Dr. Todd and his colleagues, which is indeed my pleasure. I can only agree wholeheartedly with their findings and their results. Aspiration needle biopsy in my opinion is the diagnostic method of choice in mass lesions in the outer two-thirds of the lung. When I reflect on all the useless diagnostic bronchoscopies I have done in this group of patients in former years, Willie Sutton s advice to go where the money is sounds like the wisdom of Solomon to me. My colleagues and I presented our experience with aspiration needle biopsy to this Society in Our results to date very much parallel those presented by Dr. Todd. Since 1972, we have performed 1,600 procedures, the majority for suspected cancer. There are two statistics that I think are important. The first is that it takes only an average of 12 minutes of physician time to obtain the specimen. And this is important-only 19% of our patients undergoing the procedure ultimately required thoracotomy. More often, aspiration needle biopsy spares the patient a thoracotomy than it confirms a diagnosis that necessitates operation. Anyway, we believe that the solitary circumscribed peripheral nodule to be excised does not require aspiration needle biopsy. In all large series, the complication rates for this technique are virtually superimposable. One-quarter of the patients will have a pneumothorax, and approximately half of these patients will require a chest tube. This is a statistic that you simply have to live with. Other than pneumothorax, however, the complications are virtually nonexistent. We have never

8 161 Todd et al: Aspiration Needle Biopsy seen an implantation of tumor cells, as Dr. Todd mentioned, which is often given as the reason to avoid this technique. With regard to malignant lesions, our diagnostic confirmation again is very close to the Toronto experience, 87% yield with the first procedure and 96% yield with two procedures. Procedure here is defined as at least three aspirations of the lesion at a single sitting. If for any reason the experience has been unsatisfactory in terms of specimen or in terms of thinking that we did not obtain enough tissue, we will do another total run at the lesion. In the experience of most people, this will increase the yield. One caveat about aspiration needle biopsy, which has been mentioned already, is that it requires an expert cytopathologist, and even then typing of fresh cancer cells is vastly different from the typing of exfoliated cells. One series, for instance, from Scandinavia, contrasts the accuracy of aspiration biopsy with exfoliative cytology. With each of the various cell types, the accuracy is less than would be expected with the exfoliative cells. This is experience we all have had, and, therefore, our cytopathologists will render a diagnosis only of benign or malignant. Erroneous typing can be misleading therapeutically, particularly in small cell cancer. I have two questions. Dr. Todd, what was your experience with cell typing in your aspiration needle biopsy specimens? Also, did you use a second procedure to increase your positive yield? DR. w. R. ERIC JAMIESON (Vancouver, BC, Canada): I congratulate Dr. Todd on this documentation and extensive experience from the Toronto General Hospital. In July, 1978, we initiated a cooperative effort between the cytologists and the radiologists in the taking of biopsies. Both the cytologist and the radiologist were present when the specimen was obtained, and this meant that the cytologist could indicate that he had a satisfactory specimen before the introducer was removed and before the patient was taken from the diagnostic suite. With this approach, we reduced our false negative rate to 5% only 4 patients. In this series of 82 patients, our sensitivity was 100% and specificity, 94%. I think that since we began this cooperative effort, we have had only 1 patient in whom we could get insufficient specimen for diagnosis. DR. TODD: I thank both discussants for their comments. Dr. Ferguson raised two points. He asked about the ability of our cytologists to specify the cell type in primary lung cancers. As I indicated, we have been disappointed in that ability, although in squamous cell carcinoma and adenocarcinoma it does run over 70%. Because of the problem for the cytopathologist to accurately detail oat cell carcinoma on aspiration biopsy, we do not allow that diagnosis to preclude operation in this group of patients, if there are no signs of local or distant spread. Dr. Ferguson also asked about our experience with second procedures. Out of 2,114 biopsies in this series, 197 were done a second time, and the diagnostic yield in that category was about 88%. Dr. Jamieson mentioned having both a cytopathologist and a pathologist present so that the cytopathologist could review the aspiration immediately as it is taken and indicate whether a second aspiration is necessary. Others have reported favorably on this approach. However, in addition to the analysis of the aspirated material, we washed the needle and the syringe and submitted those washings for cytological evaluation. There were a number of instances where the diagnosis was reached on these washings but not on the initial aspirate. As a result, I do not think that that approach would be applicable in our situation, because it does take a couple of hours to process the additional washings.