Prognostic value of the new IASLC/ATS/ERS classification of clinical stage IA lung adenocarcinoma.
OBJECTIVE
We analyzed and validated the prognostic utility of the new International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) for clinical stage IA lung adenocarcinoma (ADC) classification of adenocarcinoma (ADC).


METHODS
We retrospectively reviewed 347 patients with clinical stage IA nonmucinous ADC, who had undergone complete resection. The histological subtype was classified according to the predominant subtype, as proposed by the new IASLC/ATS/ERS ADC classification.


RESULTS
The histopathological subtypes, defined according to the new IASLC/ATS/ERS ADC classification, were ADC in situ (AIS) in 56 patients (16.1%), minimally invasive ADC (MIA) in 15 (4.3%), lepidic-predominant ADC in 109 (31.4%), papillary-predominant ADC in 70 (20.2%), acinar-predominant ADC in 61 (17.6%), solid-predominant ADC in 30 (8.6%), and micropapillary-predominant ADC in 6 (1.7%). The 5-year disease-free survival (DFS) rate was 100% for both AIS and MIA. All cases of recurrence involved invasive ADC. The 5-year DFS for lepidic-predominant ADC was 99.0%; acinar-predominant ADC, 82.4%; papillary-predominant ADC, 80.8%; solid-predominant ADC, 73.6%; and micropapillary-predominant ADC, 33.3%. The predominant subtype of ADC was significantly correlated with DFS (P<0.0001). Multivariate analysis indicated that the pathological stage was an independent predictor of DFS (P=0.031). Other independent predictors of increased risk of recurrence were the presence of vascular or lymphatic invasion (HR=4.96, P=0.001), and a pathological stage more advanced than IB (HR=2.87, P=0.010). The coincidence between the clinical stage and pathological stage was 79.8%. The stage migration was found in 53.3% of solid-predominat ADC and in 83.3% of micropapillary-predominant ADC.


CONCLUSIONS
The new IASLC/ATS/ERS ADC classification has prognostic value in predicting the recurrence and survival of patients with clinical stage IA ADC. The frequency of stage migration was found in more than half of solid and micropapillary predominant ADCs.
Department of Thoracic Oncology, Kanagawa Cancer Center, Yokohama, Japan.
Shuji
S
Murakami
Department of Thoracic Oncology, Kanagawa Cancer Center, Yokohama, Japan.
Hiroyuki
H
Ito
Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
Norifumi
N
Tsubokawa
Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
Takahiro
T
Mimae
Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
Shinsuke
S
Sasada
Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
Tomoharu
T
Yoshiya
Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
Yoshihiro
Y
Miyata
Department of Pathology, Kanagawa Cancer Center, Yokohama, Japan.
Tomoyuki
T
Yokose
Department of Surgical Oncology, Hiroshima University, Hiroshima, Japan.
Morihito
M
Okada
Department of Thoracic Oncology, Kanagawa Cancer Center, Yokohama, Japan. Electronic address: nakayama-h@kcch.jp.
Haruhiko
H
Nakayama
D000230:Adenocarcinoma / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging / Q000379:methods; D011379:Prognosis; D012189:Retrospective Studies
Clinical stage IA; Lung adenocarcinoma; Predominant subtype