Journal Thoracic Oncology

Abstracts Journal of Thoracic Oncology • Volume 12 Issue S1 January 2017
MA12: MISCELLANEOUS BIOLOGY/PATHOLOGY
TUESDAY, DECEMBER 6, 2016 - 14:15-15:45
MA12.06 TUMOR SPREAD THROUGH AIR SPACES (STAS) IN LUNG
SQUAMOUS CELL CANCER IS AN INDEPENDENT RISK FACTOR: A
COMPETING RISK ANALYSIS
Shaohua Lu 1 , Takashi Eguchi 2 , Kay See Tan 3 , Sarina Bains 2 , Kyuichi Kadota 1 ,
Natasha Rekhtman 1 , Prasad Adusumilli 2 , William Travis 4
1 Department of Pathology, Memorial Sloan Kettering Cancer Center, New
York/NY/United States of America, 2 Thoracic Service, Department of Surgery,
Memorial Sloan Kettering Cancer Center, New York/NY/United States of America,
3 Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New
York/NY/United States of America, 4 Dept of Pathology, Memorial Sloan Kettering
Cancer Center, New York/NY/United States of America
Background: Tumor spread through air spaces (STAS) is a recently recognized
pattern of invasion in lung adenocarcinoma, however, the incidence of and
prognostic importance of STAS have not yet been defined in squamous cell
carcinoma (SCC). Methods: In a cohort of 445 patients with p-stage I-III lung
SCC, cumulative incidence of recurrence and lung cancer-specific death (LCSD)
was evaluated by competing risks analysis and overall survival (OS) by Cox
models. Results: 76% of patients were >65 years of age. 273 patients died
during follow up, one third (91, 33.3%) died of lung cancer whereas two thirds
died of competing events or unknown cause. STAS was present in 132 (30%).
The cumulative incidence of any, distant, and locoregional recurrence as well
as LCSD were significantly higher in patients with STAS compared to those
without STAS (Figure), whereas there was no statistically significant
difference in OS. STAS was an independent predictor for both recurrence and
LCSD in multivariable analysis (p=0.034 and 0.016, respectively, Table).
Conclusion: STAS was present in one third of resected lung SCC and it was an
independent predictor of recurrence and LCSD, supporting our proposal that
STAS is a clinically important pattern of invasion and not an artifact.
Keywords: Lung cancer-specific death, Lung Squamous cell carcinoma,
invasion, Tumor spread through air spaces
MA12: MISCELLANEOUS BIOLOGY/PATHOLOGY
TUESDAY, DECEMBER 6, 2016 - 14:15-15:45
MA12.08 CLINICOPATHOLOGICAL SIGNIFICANCE OF INCREASING
PERCENTAGE OF HIGH-GRADE HISTOLOGICAL SUBTYPES IN LUNG
ADENOCARCINOMAS
Shaohua Lu 1 , Takashi Eguchi 2 , Kay See Tan 3 , James Isbell 2 , David Jones 2 ,
William Travis 1 , Prasad Adusumilli 2
1 Department of Pathology, Memorial Sloan Kettering Cancer Center, New
York/NY/United States of America, 2 Thoracic Service, Department of Surgery,
Memorial Sloan Kettering Cancer Center, New York/NY/United States of America,
3 Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New
York/NY/United States of America
Background: In early-stage lung adenocarcinomas, high-grade micropapillary
(MIP) and solid (SOL) predominant pathology is known to be associated
with worse prognosis. The aim of this study is, in addition to predominant
patterns, to investigate clinical impact of the presence of small amounts
(≥5%) as well as increasing percentage of high-grade patterns. Methods:
Invasive tumors from early-stage lung adenocarcinoma patients who
underwent curative-intent resection with no induction therapy were
investigated (N=2017; 1995-2012) (8 th edition TNM pStage I=1390, II=357,
III=270). In 388 cases, synchronous lymph node (LN) metastases were
available. Histological subtype (lepidic [LEP], acinar [ACI], papillary [PAP],
MIP, or SOL) percentages were stratified into 4 groups; 0-4%, 5-24%, 25-49%,
and 50-100%. The association between increasing percentage of patterns of
primary tumor and the incidence of lymphatic/vascular invasion, necrosis,
tumor spread through air spaces (STAS) as well as estimated 5-year cumulative
incidence of recurrence (CIR) were analyzed. The differences in distribution
of each pathological variable between 4 groups was analyzed by Chi-square
test. The percentages of histological pattern were compared between primary
tumor and LN metastasis. Results: Increasing percentage of MIP pattern is
associated with increasing incidence of lymphatic/vascular invasion, STAS,
as well as 5-year CIR (Figure 1a, p