Cribriform Pattern Identifies a Poor Prognostic Subset of Acinar Predominant Tumors in Stage I Lung Adenocarcinoma Patients
Kyuichi Kadota, Yi-Chen Yeh, Kei Suzuki, Camelia S Sima, Valerie W Rusch, Andre L Moreira, Prasad S Adusumilli, William D Travis. Memorial Sloan-Kettering Cancer Center, New York
Background: A newly proposed IASLC/ATS/ERS lung adenocarcinoma classification emphasizes the prognostic significance of histologic subtypes. In this classification, however, one limitation is that the majority of patients (approximately 40%) are classified into the acinar predominant subtype. We investigated whether cribriform pattern can further stratify the prognosis of histologic subtypes in stage I lung adenocarcinoma.
Design: H&E stained slides of 540 stage I lung adenocarcinoma patients (2002-2009) were reviewed. Tumors were classified into histologic subtypes according to the IASLC/ATS/ERS classification: adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), lepidic, papillary, acinar, micropapillary, solid predominant, invasive mucinous and colloid adenocarcinoma. The percentage of cribriform pattern was recorded in 5% increments, and we added cribriform predominant subtype. Log-rank test was used to analyze the association between histologic variables and recurrence-free probability (RFP).
Results: Patients with AIS/MIA (n=26) experienced no recurrence (3-year RFP: 100%). Patients with lepidic predominant tumors (n=76) had the low-risk of recurrence (3-year RFP: 97%). Patients with acinar (n=193), and papillary predominant tumors (n=102) had the intermediate-risk of recurrence (3-year RFP: 90% and 91%, respectively). Patients with micropapillary (n=46), solid predominant (n=71), and invasive mucinous/colloid adenocarcinoma combined group (n=26) had the high-risk for recurrence (3-year RFP: 59%, 72%, and 62%, respectively). The 3-year RFP of cribriform predominant subtype (n=16, 70%) was comparable to the high-risk group for recurrence. When looking at RFP according to cribriform pattern percentage in all cases, patients with ≥30% cribriform pattern (n=31) had marginally lower RFP (3-year RFP: 77%) than <30% cribriform pattern (n=509, 86%, p=0.047). Within patients with acinar predominant subtype, patients with ≥30% cribriform pattern (n=25) had significantly lower RFP (3-year RFP: 75%) than <30% cribriform pattern (n=168, 92%, p=0.001).
Conclusions: Cribriform pattern further stratified the acinar predominant tumors into two prognostically distinct subsets. In addition, cribriform predominant tumors may be considered as a poorly differentiated or high grade category with a high-risk for recurrence.
Tuesday, March 20, 2012 9:30 AM
Poster Session III # 314, Tuesday Morning