Adoption of Rapid On-Site Evaluation in the Routine Evaluation of Lung Cytology Specimens

Dear Editor,In the recent on Acta Cytologica, we read a relevant article titled "The World Health Organization Reporting System for Lung Cytopathology" (Fernando et al. [1] 2023). This newly proposed system for reporting pulmonary cytology specimens is intended to replace the existing reporting systems developed by the Papanicolaou Society of Cytopathology (PSC) in 2016 and another system developed by the Japan Lung Cancer Society and Japanese Society of Clinical Cytology in 2020. The WHO reporting system simplifies the diagnostic categories into a five-tier system of "Insufficient/Inadequate/Non-diagnostic," "Benign," "Atypical cells," "Suspicious for malignancy," and "malignancy." This system appears to address some pertinent questions related to the adequacy criteria of lung cytology samples and management options for intermediate malignant cytology results that remained unanswered in earlier reporting systems. Here, we highlight the role of rapid on-site evaluation (ROSE) envisaged as a management option for diagnostic categories in this system.In the WHO reporting system, sample adequacy criteria have been well characterized for all lung pathology specimens. Cases are labelled as "Non-diagnostic" when there is an adequate benign cell population but with a mass lesion in imaging. Inadequate/insufficient samples can be reduced by immediate feedback on the cellularity and quality of the specimen through rapid on-site evaluation [2]. In addition, in these cases clinicoradiological and microbiological correlation with option of more invasive procedure were suggested. The "benign" category includes inflammatory processes, benign respiratory tract neoplasms, and tumor-like lesions. The WHO reporting system entails the removal of "low-grade carcinoma" from being clubbed with the same category as benign neoplasms, one of the contentious aspects of the Papanicolaou Society of Cytopathology reporting system (Category IV). The "atypical" category includes mostly reactive changes in benign lesions with some features whereby possibility of a malignant lesion cannot be entirely excluded. This category includes cases associated with reactive changes in epithelium, like metaplasia, hyperplasia, and postinfectious and posttreatment related changes. The causative factors for these changes include the intrinsic nature of the lesion, technical issues related to material collection and processing of the material, and the expertise of the operator and pathologist. The "suspicious for malignancy" category includes cytological features insufficient in quantity and quality to qualify as malignancy. A definite therapy can be initiated after clinicoradiological correlation. However, in a minority of cases, surgical management can be undertaken without a confirmatory diagnosis; in such cases, intraoperative diagnosis is recommended. Both "Atypical" and "suspicious for malignancy" categories in EBUS-TBNA in the absence of clinicoradiological correlation warrant a repeat aspiration with ROSE and the option of cell block preparation. Employing ancillary techniques like immunocytochemistry can assist in the correct categorization of "suspicious for malignancy" cases.ROSE during EBUS-TBNA can reduce the number of passes and the need for additional bronchoscopic procedures during evaluation for the initial diagnosis of lung cancer [3]. Therefore, ROSE should be encouraged during EBUS-TBNA procedures in patients with suspected lung cancer and enlarged mediastinal or hilar lymph nodes. Also, extra passes can be requested for ancillary studies like immunocytochemistry and molecular techniques after a ROSE diagnosis of carcinoma [4]. Further, ROSE reduces the need for additional invasive procedures like mediastinoscopy and the incidence of EBUS-TBNA-related complication rates [5]. The use of ROSE also increased the proportion of cases where an adequate cell block preparation was prepared [6].To conclude, we reaffirm the relevance of the information provided in this article regarding the utility of ROSE in lung cytology, especially for EBUS-TBNA procedures in reducing the rates of "Insufficient/Inadequate/Non-diagnostic," "Atypical cells," and "Suspicious for malignancy" categories. Therefore, we propose that institutions providing pulmonary care facilitate ROSE in their bronchoscopy or operating rooms for efficient evaluation of lung cytology specimens.The authors have no conflicts of interest to declare.No funding sources.Immanuel Pradeep, Ashutosh Rath, and Jitendra Singh Nigam contributed equally to writing and reviewing the letter.