Verification bias in diagnostic accuracy studies for fine- and core needle biopsy of salivary gland lesions in otolaryngology journals: a systematic review and analysis

BACKGROUND

Diagnostic test accuracy (DTA) studies for needle biopsy are frequently published in otolaryngology journals, but this body of literature has not been assessed for verification bias.

METHODS

We conducted a systematic review of DTA studies on needle biopsy of salivary gland lesions appearing in otolaryngology journals. Studies were assessed by 2 reviewers for verification bias.

RESULTS

We identified 95 DTA studies for needle biopsy of salivary gland lesions. Eighty-one studies (84%) had verification bias. Five of the biased studies provided sufficient data to estimate the extent of bias. Verification bias was associated with an overestimate of sensitivity and an underestimate of specificity. Studies on core needle biopsy (CNB) had a lower rate of verification bias than fine-needle aspiration (FNA) studies.

CONCLUSION

Verification bias is common in DTA studies of needle biopsy for salivary gland lesions published in ear, nose, and throat (ENT) journals. Such studies overestimated sensitivity and underestimated specificity.

[Intraoperative frozen section diagnosis of head and neck tumors: possibilities, limitations, pitfalls and tips for the daily practice]

Intraoperative consultation (synonym: frozen section diagnostics) has increasingly gained significance for the daily practice in head and neck surgery. The main aim of this investigation method which is usually associated with much stress and effort is to facilitate an optimal and timely oncological surgical treatment of neoplastic diseases with a minimum rate of postoperative functional disturbance. In order to achieve this purpose pathologists are expected to deliver as much correct information as possible to accurately influence intraoperative surgical decisions. At the same time this aim should be reached without significantly and unnecessarily increasing the workload for the pathology laboratory and without significantly inducing tissue artifacts. This would otherwise negatively influence the tissue quality for permanent section examination and consequently the overall quality of diagnosis and tumor staging. Thus, the quality and efficacy of frozen sections span a spectrum with the highest quality having the least possible false negative rate on the one hand and a false positive result of approximately zero on the other hand. Sticking to this approach would result in a high positive impact on the surgical treatment of a variety of neoplastic diseases and help to minimize or even eliminate the rate of medicolegal consequences.

Usefulness of fine-needle aspiration in parotid diagnostics

PURPOSE

Fine needle aspiration (FNA) is a safe diagnostic technique that is widely employed for lesions of the head and neck. Among head and neck sites, the parotid gland is unique in the number, diversity, and peculiarity of its pathological processes. This complexity has prompted a great deal of discussion regarding the application of FNA to parotid masses, primarily focusing on the reliability of FNA as a diagnostic tool in guiding patient management.

METHODS

This review presents an analysis of the usefulness of FNA in differential diagnosis of parotid pathologies.

RESULTS

Recent studies have confirmed a wide range of accuracy rates for FNA evaluation of parotid masses, varying from 79% to 97%. These data cannot be uniformly anticipated across all diagnostic scenarios. FNA is notoriously unreliable in recognising the malignant nature of parotid carcinoma providing its precise classification and establishing its grade. A few malignant neoplasms are particularly prone to diagnostic error: acinic cell carcinoma is frequently interpreted as benign, and low-grade lymphomas are often discounted as inflammatory processes.

CONCLUSIONS

FNA cytology is useful in avoiding surgery (inflammatory lesions) or limiting surgical procedures (benign tumours). For planning the extent of surgery of malignant parotid tumours, the histological subtype and/or grade should be determined; therefore, a histological diagnosis by frozen section analysis is required. Moreover, reliance on FNA findings at the expense of clinical, radiographic, and intraoperative findings is unwarranted. Regardless of whether FNA is used routinely or selectively in patients with parotid masses, the findings should contribute to, and not replace, the overall diagnostic impression.

FROZEN SECTION FOR PAROTID SURGERY: SHOULD IT BECOME ROUTINE?

BACKGROUND

The role of fine-needle aspiration (FNA) in salivary gland lesions as a preoperative diagnosis has always been under scrutiny. Several studies have shown that frozen section (FS) is accurate for pathological diagnosis and decision-making during the surgery. This study has been carried out to assess the accuracy of FNA and FS in parotid surgeries.

METHODS

All parotid lesions removed between July 1998 and June 2003 by the Department of Otolaryngology, Head and Neck unit at Monash Medical Centre were reviewed. FNA, FS and definitive pathology were collected and discrepancies were identified.

RESULTS

Eighty-five parotid tumours had been removed. Thirty-three were malignant in which squamous cell carcinoma was the most common. FS was able to differentiate benign tumours from malignant with 100% accuracy (30 cases). FS was able to alter the surgical decisions in six cases. FNA had been carried out in 62 cases, with sensitivity and specificity of 77.2 and 90%, respectively.

CONCLUSION

Frozen section in parotid surgery is accurate, inexpensive and may add important information that alters management and improves the outcome. The use of FS routinely in parotid surgery is recommended.

Accuracy of Fine Needle Aspiration Cytology and Frozen Section Histopathology for Lesions of the Major Salivary Glands

Introduction: Identifying malignancy either preoperatively or intraoperatively can have a significant impact on the management of salivary gland tumours. We review our experience with fine needle aspiration cytology (FNAC) and frozen section (FS) for salivary gland lesions. We analyse the accuracy of both modalities and their influence on management. Materials and Methods: Retrospective review of 114 patients who underwent salivary gland surgery, 91 with intraoperative FS and 68 with preoperative FNAC. Both sets of results were compared against each other and the final histopathological diagnosis. Results: The accuracy of FS was 92.3%, with a sensitivity and specificity of 62.5% and 100%. Histologic concordance was 92.4% for benign lesions, and 100% for malignant tumours. The accuracy of FNAC was 89.7%, with a sensitivity and specificity of 100%. The non-diagnostic rate was 10.3%. Histologic concordance for FNAC was inferior to that for FS, with only 64.2% of benign lesions and 50% of malignant tumours correctly identified. FNAC did not alter the management of benign disease even when a correct diagnosis was obtained. Conclusion: Our results suggest that FNAC and FS are complementary in usefulness for malignant tumours. However, FNAC does not influence the management of benign lesions a Key words: Cryoultramicrotomy, Fine needle aspiration cytology, Frozen section, Neoplasms, Salivary glandsnd routine FNAC for every patient may not be cost-effective.

The role of fine needle aspiration in the evaluation of parotid masses

PURPOSE OF REVIEW

Fine needle aspiration is a safe diagnostic technique that is widely employed for lesions of the head and neck. Among head and neck sites, the parotid gland stands apart for the number, diversity and peculiarity of pathologic processes to target this structure. This matchless complexity has prompted a thoughtful discussion regarding the application of the fine needle aspiration to parotid masses--a discussion that has primarily focused on the reliability of the fine needle aspiration as a diagnostic tool, and on its utility in guiding patient management.

RECENT FINDINGS

Recent studies have confirmed a high overall accuracy rate for fine needle aspiration evaluation of parotid masses, ranging from 90 to 95%. At the same time, these soaring accuracy rates cannot be uniformly anticipated across all diagnostic scenarios. Fine needle aspiration is notoriously unreliable in recognizing the malignant nature of the parotid carcinoma, providing its precise classification, and establishing its grade. A few malignant neoplasms are particularly prone to diagnostic error. Acinic cell carcinoma is frequently interpreted as benign or even nonneoplastic; and low-grade lymphomas are often discounted as inflammatory processes.

SUMMARY

Parotid gland masses are not particularly conducive to diagnostic accuracy and precision by fine needle aspiration. Accordingly, indiscriminant reliance on the fine needle aspiration findings at the expense of the clinical, radiographic, and intraoperative findings is unwarranted. Whether one uses the fine needle aspiration routinely or selectively in patients with parotid masses, the fine needle aspiration findings should contribute to, not displace, the overall diagnostic impression.

Relative accuracy of fine-needle aspiration and frozen section in the diagnosis of lesions of the parotid gland

BACKGROUND

Both fine-needle aspiration (FNA) and frozen section (FS), although useful in preoperative and intraoperative management, have their advantages and pitfalls when used in the diagnosis of salivary gland lesions. The accuracy of each of these modalities has been assessed separately in many studies; a direct comparison of these techniques on a large cohort has not been well studied. Herein, we determine the relative accuracies of both FNA and FS in the diagnosis of salivary gland lesions.

METHODS

We reviewed a cohort of 220 cases of parotid gland FNA with histologic follow-up; FS was performed in 57 cases (26%). The sensitivity, specificity, and accuracy of FNA and FS were determined with respect to the final histologic diagnosis. For these calculations, benign diagnosis was considered negative, whereas a malignant diagnosis was considered positive. In addition, we re-reviewed the FNA and FS slides in cases that had conflicting FNA and FS results.

RESULTS

Of the 220 cases examined, the FNA diagnoses were as follows: benign (n = 142), malignant (n = 52), indeterminate (n = 14), and nondiagnostic (n = 12). Correlating these findings with the histologic findings, nine cases (4%) were false negative, whereas 12 (5%) were false positive. The sensitivity, specificity, and accuracy for FNA when diagnostic were 86%, 92%, and 90%, respectively. In 57 cases with FS, seven (12%) were false negative, whereas none were false positive. The FS was able to change to benign four diagnoses that were malignant by FNA and provide a diagnosis for five nondiagnostic FNAs. The sensitivity, specificity, and accuracy for FS were 77%, 100%, and 88%, respectively. The sensitivity, specificity, and accuracy for FNA and FS combined were 90%, 100%, and 95%, respectively.

CONCLUSIONS

Both FNA and FS provide a similar accuracy. FS may be useful if FNA is nondiagnostic and may also be useful in confirming or refuting malignancy in some cases. Hence, both techniques are complementary to each other in the diagnosis of salivary gland lesions.

Management of primary malignant epithelial parotid tumors

Parotid cancers are infrequently encountered. These tumors carry a prolonged risk of recurrence and metastasis. Controversies surrounding pre-treatment evaluation by imaging and fine needle aspiration, utility of operative frozen section are partly resolved. Though surgery remains the mainstay of treatment, radiation is being recognized as a useful adjuvant. Facial nerve preservation is one of the important goals at surgery. The role of chemotherapy is still investigational. The prognosis and necessity of elective neck treatment are mainly guided by the tumor grade and stage.

Diagnostic accuracy of fine-needle aspiration cytology and frozen section in primary parotid carcinoma

BACKGROUND

The low incidence and histologic heterogeneity of primary parotid carcinomas makes it difficult to evaluate the value of preoperative fine-needle aspiration cytology (FNAC) and intraoperative frozen section (FS) analysis. In the current study, the authors reviewed a single institution's experience regarding the preoperative and intraoperative diagnostic value of FNAC and FS in primary salivary gland carcinomas.

METHODS

Between January 1990 and December 2002, 108 primary parotid carcinomas were resected at the Department of Otorhinolaryngology, Head and Neck Surgery at the University of Berne, Inselspital (Berne, Switzerland). Included in the study were a total of 101 carcinomas with preoperative FNAC results in 88 tumors and/or intraoperative FS results in 45 tumors. In a retrospective study, the results of FNAC and FS were analyzed and compared with the corresponding histopathologic diagnoses.

RESULTS

The cytologic findings were true-positive for malignancy in 63 tumors (72%), false-negative in 22 tumors (25%), and nondiagnostic in 3 tumors (3%). The tumor grading was correct in 29 of 63 tumors (46%), and the exact tumor typing was correct in 27 of 63 (43%) true-positive tumors. The FS findings were true-positive for malignancy in 43 of 45 tumors (96%), the tumor grading was correct in 35 of 45 tumors (78%), and the tumor typing was correct in 32 of 45 tumors (71%). Overall, at the time of surgery, of the 101 parotid carcinomas, the tumor was known to be malignant in 83 tumors (82%), and the correct grade and the exact tumor type were known in 55 tumors (54%) and 48 tumors (48%), respectively.

CONCLUSIONS

FNAC recognized malignancy in 72% of tumors, but it could not be relied upon to provide an accurate tumor grading or typing. Therefore, FNAC alone is not prone to determine the surgical management of primary parotid carcinomas. The current analysis showed the statistically significant superiority of FS compared with FNAC regarding the diagnosis of malignancy, tumor grading, and tumor typing in primary parotid carcinomas.

Fine-needle Aspiration Cytology in the Management of Salivary Gland Tumors: An Australian Experience

We conducted a retrospective study of 104 cases of salivary gland tumors that were initially assessed by fine-needle aspiration biopsy (FNAB). Based on subsequent histopathologic analysis of excised specimens, we found that preoperative FNAB was highly sensitive and specific for both benign and malignant tumors—including the most common, pleomorphic adenomas and squamous cell carcinomas, respectively. Despite its possible drawbacks, we conclude that preoperative FNAB is a useful tool in the management of salivary gland tumors.

Accuracy of fine-needle aspiration cytology of salivary gland lesions in the netherlands cancer institute

BACKGROUND

To evaluate the accuracy of fine-needle aspiration cytology (FNAC) in salivary gland lesions in a tertiary referral center.

METHODS

A cytohistologic correlation study was performed using an automated pathology database of 1023 patients diagnosed with a salivary gland lesion.

RESULTS

In 388 cases, both cytology and histology were available. Using cytologic confirmation of malignancy as the starting point, the sensitivity, specificity, and accuracy of FNAC in this study were 88%, 99%, and 96%, respectively. Exact type-specific concordance of the malignant diagnosis was achieved in 66 (88%) of 75 cases and in 211 (95%) of 223 benign cases. Of the 19 cases with a cytologic diagnosis "cyst," four proved to be malignant. A non-neoplastic lesion at cytology proved to be correctly classified in 53 (68%) of 80 patients.

CONCLUSIONS

Our data show that cytology is a reliable and accurate technique to assess lesions of the salivary glands. The cytologic diagnosis of "cysts" and "non-neoplastic lesions" should be interpreted with caution.

Primary parotid gland Hodgkin's lymphoma

Hodgkin's lymphoma with its primary manifestation in the parotid gland is an exceedingly rare entity and is not usually suspected in the initial evaluation of a parotid mass. Because it is not suspected, the results of fine-needle aspiration cytology are often misleading, and parotidectomy is needed for a definitive diagnosis. The most common subtype encountered is lymphocyte-predominant. The prognosis is favorable; the 5-year survival rate exceeds 90%. Treatment consists of chemotherapy, radiotherapy, or both. A case of primary parotid gland Hodgkin's lymphoma is presented along with a review of the literature and a discussion of the evaluation and management of this rare entity.

Frozen section during parotid surgery revisited: efficacy of its applications and changing trend of indications

BACKGROUND

Efficacy of frozen sections was assessed in terms of its various applications. The changing role of frozen sections in parotid surgery was examined.

METHOD

Records of parotid operations over a 15-year period in a University Department of Head & Neck Surgery were reviewed.

RESULTS

Of 241 operations, frozen sections were performed on 32. Applications of frozen sections included diagnosis, margin clearance, and checking suspicious lymph nodes and nerve invasion. The false-positive rate for malignancy was 12.5%. Margins may still be involved despite correct tissue diagnosis from sampling error. No inappropriate surgery resulted from the information obtained. With the advent of fine-needle aspiration, frozen sections were less often called for and a shift from a diagnostic role to margin checking was seen. Frozen sections picked up all unsuspected malignant tumors.

CONCLUSION

Frozen sections are helpful when interpreted cautiously, but clinical assessment and fine-needle aspiration are also important components in the workup.

Fine-needle aspiration: survey of clinical utility

OBJECTIVES

The goal was to determine the features of clinical usage of fine-needle aspiration (FNA) in this country in terms of utilization, indications, and practice and demographic characteristics of those who use FNA.

STUDY DESIGN

A survey was mailed to otolaryngologist-head and neck surgeons (OTO-HNSs) in the United States. The results were totaled and analyzed for indications for FNA performance, practice setting, age, and geographic location of practitioners.

RESULTS

The most common indications for use of FNA were in the diagnoses of neck, thyroid, salivary, and other masses in the head and neck. In the survey group the average number of FNAs performed per month was 4.7 per respondent practitioner. FNA was statistically related to age (older physicians performed it less) and region of the country. FNAs are performed at a lower rate in the West.

CONCLUSIONS

FNA is a commonly performed procedure. Certain groups of OTO-HNSs (older, located in western states) do not perform FNA as commonly as other OTO-HNSs. Further education regarding the merits of FNA is needed.

Fine Needle Aspiration Biopsies of the Head and Neck: The Surgical Pathologist's Perspective

Masses of the head and neck comprise a variety of benign and malignant tumors and tumor-like conditions, which may present diagnostic challenges to the surgical pathologist and surgeon. Fine needle aspiration cytology is an increasingly popular technique in the initial evaluation of such lesions. The high diagnostic accuracy of this technique makes it generally preferable to traditional surgical biopsy. It is particularly useful in the sampling of histologically uniform neoplasms of the salivary glands, identification of classical papillary carcinoma and medullary carcinoma of the thyroid, separation of colloid goiter from follicular neoplasms, and confirmation of clinically suspicious lymph node metastases in cases with already documented malignant diseases. Despite its usefulness, aspiration cytology of head and neck lesions has certain inherent pitfalls, and these are briefly examined in this review. Int J Surg Pathol 8(1):17-28, 2000

Malignant epithelial parotid gland tumours: analysis and results in 65 previously untreated patients

BACKGROUND

Optimal management of malignant epithelial parotid tumours requires knowledge of the available therapeutic modalities and the different biological characteristics. The aim of the study was to review the characteristics of patients at presentation, histological classification, disease-free and overall survival rates, and the results of the applied treatment policy regarding the facial nerve and neck.

METHODS

Between 1974 and 1995 a total of 65 patients was treated with curative intent for a previously untreated malignant epithelial parotid gland tumour. All patients underwent some type of parotidectomy, 20 of whom had an en bloc radical neck dissection. In selected cases the facial nerve or its branches were peeled off the tumour thus violating the objective of tumour-free margins and relying heavily on the efficacy of postoperative radiotherapy. In total 51 patients received postoperative radiotherapy. None of the patients was lost to follow-up.

RESULTS

There were 12 locoregional failures (18 per cent). In only one of these 12 patients was salvage therapy successful; the remaining 11 patients died from the tumour. All but one of the eight patients with distant metastasis only died from the tumour. The estimated 5- and 10-year disease-free rates were 68 and 59 per cent respectively. The corresponding survival rates were 75 per cent and 67 per cent. A significant relationship could be observed between tumour stage and survival. The presence of lymph node metastases proved to be the strongest single prognostic factor.

CONCLUSION

In selected cases a conservative approach towards the facial nerve is justified.

The accuracy of clinical examination versus frozen section in the diagnosis of parotid masses

PURPOSE

This study evaluated the role of clinical examination and frozen sections in the diagnosis and management of parotid masses.

PATIENTS AND METHODS

One hundred seventy patients underwent parotidectomy. Of these, the data on 65 were analyzed, with emphasis on accuracy of the clinical diagnosis and frozen section results compared with the final histologic diagnosis.

RESULTS

The results showed that the sensitivity of frozen sections for malignancy was 93.3%, and the specificity for a benign tumor was 95.74%, with a 4.2% false-negative rate and a 6.7% false-positive rate. Of the 65 patients, 58 patients had an explicit clinical diagnosis; 88.4% were correctly identified as benign tumors, and 78.6% were correctly diagnosed as malignancies. The false-positive and false-negative rates were 21.4% and 7.0%, respectively.

CONCLUSIONS

The results of this study suggest that clinical examination can provide information that is not very reliable, and the surgical plan should be based on intraoperative frozen sections rather than the history and clinical features.