Elastic Tissue Stain: A Valuable Diagnostic Tool for the Assessment of Visceral Pleura Invasion in Patients with Non-Small Cell Lung Cancer
M Kamionek, A Akalin, K Dresser, S Baker, A Fraire. University of Massachusetts Medical School, Worcester, MA
Background: Breaching of the visceral pleura by tumor cells has long been known to negatively impact the outcome of patients with lung cancer. A recent proposal for the classification of visceral pleural invasion (VPI) defines VPI as invasion beyond pleural elastic lamina (PL1), with PL2 signifying tumor at the pleural surface and PL3 denoting tumor in chest wall tissue. This study was undertaken to test the above cited classification proposal and to determine the potential staging value of elastic tissue staining in a cohort of 96 surgically resected patients with non-small cell tumors 3 cm or less in diameter, initially staged as T1N0M0 on the basis of H&E stain alone.
Design: All of the 96 evaluated tumors were subpleurally located but actual distances of tumors to the pleural surface varied considerably requiring segregation of the tumors into 2 groups: less than 0.2 cm and 0.2 cm or more. Breaching of elastic lamina was independently evaluated by 3 observers. Unanimity was defined as uniformity of result by 3 observers. Resolution of discrepancies was achieved by subsequent joint review.
Results: Consensus diagnoses were achieved in all 96 cases by initial unanimity in 57 cases or subsequent joint review in 39 cases. Among the 96 cases, 72 (75%) were classified as PL0 requiring no TNM upstaging. However, 18 (18.75%) were classified as PL1 requiring upstaging to T2N0M0.
The majority (71) of the cases had tumor located 0.2 cm or less from pleura. In this subset of patients the proportion of understaged tumors was greater (25.35%). Only one patient was classified as PL2, and five difficult to categorize cases were classified as PLX (5.2%).
Conclusions: Our study suggests that the use of elastic tissue stain allows recognition of a sizable proportion (18.75%) of understaged lung cancer patient who may otherwise be denied potential benefits of adjuvant chemotherapy. Our study further suggests that elastic tissue staining is particularly valuable in the subset of patients in whom the lung cancers were closest (within 0.2cm) to the pleura. In this subset, the proportion of understaged patients was 25.35%.
Wednesday, March 24, 2010 9:30 AM
Poster Session V # 254, Wednesday Morning