Assessing the Pleura and Other Objective and Routine Findings Predicting Outcome with Stage 1 Non-Small Cell Lung Carcinoma.
Susi K Jeffus, Alykhan S Nagji, Benjamin D Kozower, David R Jones, Edward B Stelow. University of Virginia, Charlottesville
Background: Stage 1 non-small cell lung carcinomas (NSCLC) have an excellent prognosis. Larger tumor size has been well documented to increase the risk for adverse outcome. The meaning of visceral pleural involvement is less clear, especially as a number of studies have shown that this finding is assessed by different means throughout the pathology community and, furthermore, there is significant interobserver variability associated with its assessment. Other findings, including identifying squamous or glandular differentiation can be no less troublesome, and some immunohistochemical stains are now used to assess differentiation at some institutions. Here, we investigate the use of routine gross, histologic and immunohistochemical findings for predicting behavior of stage 1 NSCLC.
Design: 78 cases of completely resected NSCLC were used. Smoking history and patient age and sex were recorded. Tumor size, differentiation (by H&E), and distance from visceral pleural surface were recorded. A tissue microarray was constructed and immunohistochemistry was performed with antibodies to TTF1, p63, mutant EGFR (L858M and E746-A750del), and ALK1. All results were compared to outcome.
Results: Patients included 36 men and 42 women; 7 were non-smokers and the mean age was 68 years. Tumor size was as follows: >5cm (n=3; 4%), >3cm and <5cm (n=19; 24%), >2cm and <3cm (n=22; 28%), and <2 cm (n=34; 44%). 33 tumors (42%) extended to within 1 mm or less of the visceral pleural surface. Histologically, 32 tumors were squamous cell carcinoma (41%), 38 were adenocarcinomas (49%) (7 were non-mucinous bronchioloalveolar carcinomas), 2 were adenosquamous carcinomas (3%), and 6 were undifferentiated carcinomas (8%). 9 tumors had lymphovascular space invasion. 48% of tumors were immunoreactive with antibodies to p63 and 56% with antibodies to TTF1. 3 tumors were immunoreactive with antibodies to mutant EGFR (4%) and none with antibodies to ALK1. There were 14 recurrences and/or metastases (18%). Smoking, non-squamous phenotype (by H&E), undifferentiated phenotype and distance of less than 1 mm from the pleural surface were the greatest predictors of adverse outcome (p=0.16, 0.03, 0.001, 0.07, respectively).
Conclusions: Our results confirm that histologic sub-typing (by H&E) and grading of NSCLC (especially identifying undifferentiated tumors) are important for predicting behavior. Of note, measurement of tumor from pleural surface may be a more reproducible method for predicting behavior than assessment of pleural invasion.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 271, Tuesday Afternoon