- Email: [email protected]
Insights concerning partial verification bias in retrospective FNAC studies
LETTERS TO THE EDITOR
594
Insights concerning partial verification bias in retrospective FNAC studies In reply: We thank Dr. Schmidt for suggesting the estimation of partial verification bias in our study.1 Fine-needle aspiration cytology (FNAC) is a valuable tool that has been used to diagnose head and neck lesions in several centers around the world, including the Piracicaba Dental SchooldUNICAMP and University of Sao Paulo Clinic’s Hospital, a multispecialized reference center in Brazil.2 We understand that in accuracy studies designed from tested exam to the “gold standard,” in this case, from the cytopathology report to histopathologic confirmation, the absence of histopathologic evaluation in a large number of negative cases will introduce partial verification bias. However, in our study, we believe that this effect was less relevant. This assumption is based on the fact that in our retrospective study, case selection did not start with the cytopathology; conversely, case selection was based primarily on the presence of histopathologic specimens with neoplastic lesions. Thus, the reported sensitivity and specificity are related to the patients who underwent surgical procedures and the comparison of benign and malignant neoplasia, not the presence or absence of neoplasia. It was not our primary intention to extrapolate these data for all FNAC analyses and for the neoplasia versus nonneoplasia comparison. In such a case, another study design would be necessary, preferably a prospective study with specific ethical authorization to perform histopathologic examinations of specimens from patients with negative results on cytology, which might avoid relevant partial verification bias.3,4 Additionally, our diagnostic accuracy, sensitivity, and specificity were similar to those observed in other important studies that performed FNAC on salivary gland lesions using a similar approach (retrospective data).5-8 Lastly, considering the primary goal of this study and its retrospective design, in which case selection was based on the presence of a histopathologic diagnosis, it was not possible to retrieve FNAC specimens from all patients, including those without neoplasia and patients clinically followed up. Katya Pulido Díaz, DDS, PhD Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School
OOOO May 2015
State University of Campinas (FOP-UNICAMP) Piracicaba, São Paulo State Brazil Renê Gerhard, MD, PhD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil Regina Barros Domingues, MD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil Leandro Liporoni Martins, MD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil Ana Carolina Prado Ribeiro, DDS, PhD Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School State University of Campinas (FOP-UNICAMP) Piracicaba São Paulo State Brazil Márcio Ajudarte Lopes, DDS, PhD Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School State University of Campinas (FOP-UNICAMP) Piracicaba São Paulo State Brazil Paulo Campos Carneiro, MD, PhD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil
OOOO Volume 119, Number 5
LETTERS TO THE EDITOR
595
Pablo Agustin Vargas, DDS, PhD, FRCPath* Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School State University of Campinas (FOP-UNICAMP) Piracicaba São Paulo State Brazil *
Correspondence: [email protected] REFERENCES 1. Schmidt RL, Factor RE. Researchers should be aware of partial verification bias in diagnostic accuracy studies. Oral Surg Oral Med Oral Pathol Oral Radiol. 2015;119:593. 2. Díaz KP, Gerhard R, Domingues RB, et al. High diagnostic accuracy and reproducibility of fine-needle aspiration cytology for diagnosing salivary gland tumors: Cytohistologic correlation in 182 cases. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014;118:226-235. 3. Schmidt RL, Jedrzkiewicz JD, Allred RJ, Matsuoka S, Witt BL. Verification bias in diagnostic accuracy studies for fine- and core needle biopsy of salivary gland lesions in otolaryngology journals: A systematic review and analysis. Head Neck. 2014;36:1654-1661. 4. Schmidt RL, Factor RE. Understanding sources of bias in diagnostic accuracy studies. Arch Pathol Lab Med. 2013;137:558565. 5. Stramandinoli RT, Sassi LM, Pedruzzi PA, et al. Accuracy, sensitivity and specificity of fine needle aspiration biopsy in salivary gland tumours: A retrospective study. Med Oral Patol Oral Cir Bucal. 2010;15:e32-e37. 6. Singh Nanda KD, Mehta A, Nanda J. Fine-needle aspiration cytology: A reliable tool in the diagnosis of salivary gland lesions. J Oral Pathol Med. 2012;41:106-112. 7. Al-Khafaji BM, Nestok BR, Katz RL. Fine-needle aspiration of 154 parotid masses with histologic correlation: Ten-year experience at the University of Texas M. D. Anderson Cancer Center. Cancer. 1998;84:153-159. 8. Zhang S, Bao R, Bagby J, Abreo F. Fine needle aspiration of salivary glands: 5-year experience from a single academic center. Acta Cytol. 2009;53:375-382. http://dx.doi.org/10.1016/j.oooo.2015.01.018
Intradisciplinary approach: The end of a love story To the Editor: I have read with concern the article by Widmer et al.,1 published recently in this journal, about a case of “atypical TMJ [temporomandibular joint] pain.” I would rather call it “atypical management of TMJ pain!!” The authors presented no more than a classic case of TMJ osteoarthritis; however, I am disappointed that the case mismanagement was merely because of the authors’ failure to incorporate an oral and maxillofacial radiologist into their team. It is well documented that the diagnosis of TMJ osteoarthritis is achieved primarily on clinical and imaging grounds.2 A surgical diagnosis is not required for this condition. On the other hand, the authors listed three
differential diagnoses: osteoarthritis, metastasis, and aneurysmal bone cyst; however, I do not know how osteoarthritis could be included with metastasis and aneurysmal bone cyst in the differential diagnosis. There is no diagnostic justification for the patient’s exposure to bone scintigraphy and surgical biopsy. The diagnosis of TMJ osteoarthritis could have been achieved by cone beam computed tomography imaging. The findings are strongly indicative of degenerative joint disease. The lytic lesion is typical of a subchondral “cyst.” The margins are round and smooth and surrounded by areas of sclerosis, suggesting a chronic inflammatory process. This area of subchondral degeneration may appear enlarged and multiple in advanced cases. Furthermore, there is narrowing of the joint cavity, flattening of the condylar head and osteophyte formation at the lateral aspect of the equator of the condyle. Flattening and sclerosis are also appreciated in the temporal component of the joint. The diagnosis could have been made at this point. Additional examination would include only magnetic resonance imaging (T1- and T2-weighted sequences) for evaluation of the disc morphology and position, retrodiscal ligaments, joint effusion, lateral pterygoid muscle, and medullary component of the condylar head in terms of bone marrow edema and/or necrosis. An interdisciplinary approach in managing this patient would have spared the patient excessive exposure and surgical intervention/complications. However, the authors were tight-lipped about the surgical procedure and postoperative follow-up. Treatment of TMJ osteoarthritis should be directed toward relieving joint stress (e.g., splint therapy, occlusal adjustment), relieving pain (e.g., non-steroidal anti-inflammatory drugs), and restoring joint function (e.g., physiotherapy). A multidisciplinary approach can be very effective, as one specialist could offer expertise that the others lack, especially when dealing with an abnormality. The interdisciplinary approach brings collaborative elements that allow all specialists involved to conduct a dialogue concerning appropriate patient care.3,4 I hope the authors take the interdisciplinary approach into consideration for optimal patient care and management. Galal Omami, BDS, MSc, MDentSc* University of Hong Kong The Prince Philip Dental Hospital Hong Kong *
Correspondence: [email protected] REFERENCES 1. Widmer CG, Wold CJ, Stoll EM, Dolwick MF. Atypical temporomandibular joint pain: A case report. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014;118:e170-e174.
594
Insights concerning partial verification bias in retrospective FNAC studies In reply: We thank Dr. Schmidt for suggesting the estimation of partial verification bias in our study.1 Fine-needle aspiration cytology (FNAC) is a valuable tool that has been used to diagnose head and neck lesions in several centers around the world, including the Piracicaba Dental SchooldUNICAMP and University of Sao Paulo Clinic’s Hospital, a multispecialized reference center in Brazil.2 We understand that in accuracy studies designed from tested exam to the “gold standard,” in this case, from the cytopathology report to histopathologic confirmation, the absence of histopathologic evaluation in a large number of negative cases will introduce partial verification bias. However, in our study, we believe that this effect was less relevant. This assumption is based on the fact that in our retrospective study, case selection did not start with the cytopathology; conversely, case selection was based primarily on the presence of histopathologic specimens with neoplastic lesions. Thus, the reported sensitivity and specificity are related to the patients who underwent surgical procedures and the comparison of benign and malignant neoplasia, not the presence or absence of neoplasia. It was not our primary intention to extrapolate these data for all FNAC analyses and for the neoplasia versus nonneoplasia comparison. In such a case, another study design would be necessary, preferably a prospective study with specific ethical authorization to perform histopathologic examinations of specimens from patients with negative results on cytology, which might avoid relevant partial verification bias.3,4 Additionally, our diagnostic accuracy, sensitivity, and specificity were similar to those observed in other important studies that performed FNAC on salivary gland lesions using a similar approach (retrospective data).5-8 Lastly, considering the primary goal of this study and its retrospective design, in which case selection was based on the presence of a histopathologic diagnosis, it was not possible to retrieve FNAC specimens from all patients, including those without neoplasia and patients clinically followed up. Katya Pulido Díaz, DDS, PhD Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School
OOOO May 2015
State University of Campinas (FOP-UNICAMP) Piracicaba, São Paulo State Brazil Renê Gerhard, MD, PhD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil Regina Barros Domingues, MD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil Leandro Liporoni Martins, MD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil Ana Carolina Prado Ribeiro, DDS, PhD Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School State University of Campinas (FOP-UNICAMP) Piracicaba São Paulo State Brazil Márcio Ajudarte Lopes, DDS, PhD Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School State University of Campinas (FOP-UNICAMP) Piracicaba São Paulo State Brazil Paulo Campos Carneiro, MD, PhD Division of Anatomic Pathology Hospital das Clínicas Faculty of Medicine University of São Paulo (HC-FMUSP) São Paulo State Brazil
OOOO Volume 119, Number 5
LETTERS TO THE EDITOR
595
Pablo Agustin Vargas, DDS, PhD, FRCPath* Department of Oral Diagnosis Division of Oral Pathology Piracicaba Dental School State University of Campinas (FOP-UNICAMP) Piracicaba São Paulo State Brazil *
Correspondence: [email protected] REFERENCES 1. Schmidt RL, Factor RE. Researchers should be aware of partial verification bias in diagnostic accuracy studies. Oral Surg Oral Med Oral Pathol Oral Radiol. 2015;119:593. 2. Díaz KP, Gerhard R, Domingues RB, et al. High diagnostic accuracy and reproducibility of fine-needle aspiration cytology for diagnosing salivary gland tumors: Cytohistologic correlation in 182 cases. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014;118:226-235. 3. Schmidt RL, Jedrzkiewicz JD, Allred RJ, Matsuoka S, Witt BL. Verification bias in diagnostic accuracy studies for fine- and core needle biopsy of salivary gland lesions in otolaryngology journals: A systematic review and analysis. Head Neck. 2014;36:1654-1661. 4. Schmidt RL, Factor RE. Understanding sources of bias in diagnostic accuracy studies. Arch Pathol Lab Med. 2013;137:558565. 5. Stramandinoli RT, Sassi LM, Pedruzzi PA, et al. Accuracy, sensitivity and specificity of fine needle aspiration biopsy in salivary gland tumours: A retrospective study. Med Oral Patol Oral Cir Bucal. 2010;15:e32-e37. 6. Singh Nanda KD, Mehta A, Nanda J. Fine-needle aspiration cytology: A reliable tool in the diagnosis of salivary gland lesions. J Oral Pathol Med. 2012;41:106-112. 7. Al-Khafaji BM, Nestok BR, Katz RL. Fine-needle aspiration of 154 parotid masses with histologic correlation: Ten-year experience at the University of Texas M. D. Anderson Cancer Center. Cancer. 1998;84:153-159. 8. Zhang S, Bao R, Bagby J, Abreo F. Fine needle aspiration of salivary glands: 5-year experience from a single academic center. Acta Cytol. 2009;53:375-382. http://dx.doi.org/10.1016/j.oooo.2015.01.018
Intradisciplinary approach: The end of a love story To the Editor: I have read with concern the article by Widmer et al.,1 published recently in this journal, about a case of “atypical TMJ [temporomandibular joint] pain.” I would rather call it “atypical management of TMJ pain!!” The authors presented no more than a classic case of TMJ osteoarthritis; however, I am disappointed that the case mismanagement was merely because of the authors’ failure to incorporate an oral and maxillofacial radiologist into their team. It is well documented that the diagnosis of TMJ osteoarthritis is achieved primarily on clinical and imaging grounds.2 A surgical diagnosis is not required for this condition. On the other hand, the authors listed three
differential diagnoses: osteoarthritis, metastasis, and aneurysmal bone cyst; however, I do not know how osteoarthritis could be included with metastasis and aneurysmal bone cyst in the differential diagnosis. There is no diagnostic justification for the patient’s exposure to bone scintigraphy and surgical biopsy. The diagnosis of TMJ osteoarthritis could have been achieved by cone beam computed tomography imaging. The findings are strongly indicative of degenerative joint disease. The lytic lesion is typical of a subchondral “cyst.” The margins are round and smooth and surrounded by areas of sclerosis, suggesting a chronic inflammatory process. This area of subchondral degeneration may appear enlarged and multiple in advanced cases. Furthermore, there is narrowing of the joint cavity, flattening of the condylar head and osteophyte formation at the lateral aspect of the equator of the condyle. Flattening and sclerosis are also appreciated in the temporal component of the joint. The diagnosis could have been made at this point. Additional examination would include only magnetic resonance imaging (T1- and T2-weighted sequences) for evaluation of the disc morphology and position, retrodiscal ligaments, joint effusion, lateral pterygoid muscle, and medullary component of the condylar head in terms of bone marrow edema and/or necrosis. An interdisciplinary approach in managing this patient would have spared the patient excessive exposure and surgical intervention/complications. However, the authors were tight-lipped about the surgical procedure and postoperative follow-up. Treatment of TMJ osteoarthritis should be directed toward relieving joint stress (e.g., splint therapy, occlusal adjustment), relieving pain (e.g., non-steroidal anti-inflammatory drugs), and restoring joint function (e.g., physiotherapy). A multidisciplinary approach can be very effective, as one specialist could offer expertise that the others lack, especially when dealing with an abnormality. The interdisciplinary approach brings collaborative elements that allow all specialists involved to conduct a dialogue concerning appropriate patient care.3,4 I hope the authors take the interdisciplinary approach into consideration for optimal patient care and management. Galal Omami, BDS, MSc, MDentSc* University of Hong Kong The Prince Philip Dental Hospital Hong Kong *
Correspondence: [email protected] REFERENCES 1. Widmer CG, Wold CJ, Stoll EM, Dolwick MF. Atypical temporomandibular joint pain: A case report. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014;118:e170-e174.