Prognostic Significance of Cytologic Features of Lung Adenocarcinoma, Mixed Subtype
CS Sigel, DE Rudomina, N Rekhtman, WD Travis, AL Moreira. Memorial Sloan-Kettering Cancer Center, New York
Background: Adenocarcinoma (AD) mixed subtype, the most common histologic type of lung cancer, is characterized by a variety of different architectural patterns. Recently, a three-tiered histologic pattern-based grading system was developed for stage I lung AD which stratified patients into low, intermediate, and high risk categories for disease recurrence. However, many lung cancer patients present with inoperable disease and cytology may serve as the primary method for diagnosis. Attempts to correlate architectural arrangements between parallel cytologic and histologic preparations have not been successful. Therefore, we evaluated the cytomorphologic features of AD in patients previously scored by a histologic grading scheme to identify features of potential prognostic significance.
Design: Retrospectively, we reviewed the FNA specimens from 79 patients with mixed subtype ADs while blinded to a risk-stratification score previously assigned using a histologic pattern-based grading system. Specimens consisted of Diff Quik, H&E, Papanicolau, and ThinPrep stained slides. The following cytomorphologic features were evaluated: cell groups (flat sheets vs. 3D clusters vs. single cells), nuclei (size variability, shape, and contour), nucleoli (single vs. multiple and/or macronucleoli), presence of nuclear inclusions, chromatin (fine, coarse, or clumped), and the quality of the smear background. Then, we grouped the specimens according to the three grades of histologic tumor differentiation and analyzed the distribution of these cytologic characteristics.
Results: Histologically well-differentiated tumors correlated with the following cytomorphological characteristics: a clean background (100%), small nuclear size (<5x area of a resting lymphocyte) (p=0.0372), a predominance of flat sheets (p=0.0001), single nucleoli, and nuclear size uniformity. Features correlating with poor histologic differentiation included a wide variation in nuclear size, giant tumor nuclei, and a predominance of 3D clusters (p=0.0001). There was no difference among the grades of tumor with regard to the presence of nuclear inclusions, the presence of single tumor cells, or the relative prominence of nucleoli (p>0.05).
Conclusions: We have identified several distinctive cytologic features of AD, mixed subtype, that correlate with levels of histologic differentiation shown to have prognostic significance.
Wednesday, March 24, 2010 9:30 AM
Poster Session V # 249, Wednesday Morning