NON‐GYNAECOLOGICAL CYTOLOGY: THE CLINICIAN'S VIEW
Authors: Penman I. 
Published: August 2006

There is increased recognition of the importance of accurate staging of malignancies of the GI tract and lung, greater use of neoadjuvant therapies and more protocol‐driven management. This is particularly important where regional lymph node involvement significantly impacts on curability. Multidetector CT and PET scanning have resulted in greater detection of potential abnormalities which, if positive for malignancy, would change management. There is also a greater recognition that many enlarged nodes may be inflammatory and that size criteria alone are unreliable in determining involvement. In other situations, especially pancreatic masses, not all represent carcinoma as focal chronic pancreatitis, autoimmune pancreatitis etc can catch out the unwary. A preoperative tissue diagnosis is essential and even if unresectable, oncologists are increasingly reluctant to initiate chemotherapy or enroll patients into trials without this. The approach to obtaining tissue is often hampered by the small size or relative inaccessibility of lesions by percutaneous approaches. As such novel techniques such as endoscopic ultrasound (EUS) guided FNA have been developed. A 120cm needle is passed through the instrument and, under real‐time visualisation, through the gastrointestinal wall to sample adjacent lymph nodes or masses. Multiple studies have demonstrated the safety and performance of this technique. In oesophageal cancer, confirmation of node positivity by has a major negative influence on curative resection rates and will often lead to a decision to use neoadjuvant chemotherapy or a non‐operative approach. Sampling of lymph nodes at the true coeliac axis upstages the patient to M1a status (stage IV) disease and makes the patient incurable. In NSCLC, subcarinal lymph nodes are frequently present but may be inflammatory. If positive these represent N2 (stage IIIA) disease and in most centres again makes the patient inoperable. Access to these lymph nodes would otherwise require mediastinosocopy whereas this can be done simply, safely and quickly by EUS. Overall the sensitivity for EUS – FNA of mediastinal or upper abdominal lymph nodes is 83–90% with an accuracy of 80–90%. In pancreatic cancer performance is less good but pooled analysis of published studies indicates a sensitivity of 85% and accuracy of 88%. In a recent spin‐off from EUS, endobronchial ultrasound (EBUS) instruments have been developed and the ability to sample anterior mediastinal nodes has been demonstrated. It is likely that this EBUS – FNA technique will become increasingly utilised and may replace mediastinoscopy. The development of techniques such as EUS and EBUS to allow FNA sampling of lesions has increased the role of non‐gynaecological cytology significantly in recent years. Cytology therefore remains important for a broad range of specialties and there is ongoing need for careful and close co‐operation between cytologists and clinicians in these specialties.

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