A Grading System for Invasive Pulmonary Adenocarcinoma: A Proposal From the International Association for the Study of Lung Cancer Pathology Committee.
Abstact
A grading system for pulmonary adenocarcinoma has not been established. The International Association for the Study of Lung Cancer pathology panel evaluated a set of histologic criteria associated with prognosis aimed at establishing a grading system for invasive pulmonary adenocarcinoma.
A multi-institutional study involving multiple cohorts of invasive pulmonary adenocarcinomas was conducted. A cohort of 284 stage I pulmonary adenocarcinomas was used as a training set to identify histologic features associated with patient outcomes (recurrence-free survival [RFS] and overall survival [OS]). Receiver operating characteristic curve analysis was used to select the best model, which was validated (n = 212) and tested (n = 300, including stage I-III) in independent cohorts. Reproducibility of the model was assessed using kappa statistics.
The best model (area under the receiver operating characteristic curve [AUC] = 0.749 for RFS and 0.787 for OS) was composed of a combination of predominant plus high-grade histologic pattern with a cutoff of 20% for the latter. The model consists of the following: grade 1, lepidic predominant tumor; grade 2, acinar or papillary predominant tumor, both with no or less than 20% of high-grade patterns; and grade 3, any tumor with 20% or more of high-grade patterns (solid, micropapillary, or complex gland). Similar results were seen in the validation (AUC = 0.732 for RFS and 0.787 for OS) and test cohorts (AUC = 0.690 for RFS and 0.743 for OS), confirming the predictive value of the model. Interobserver reproducibility revealed good agreement (k = 0.617).
A grading system based on the predominant and high-grade patterns is practical and prognostic for invasive pulmonary adenocarcinoma.
Authors
- Beasley MB
- Borczuk A
- Botling J
- Brambilla E
- Bubendorf L
- Chen G
- Chou TY
- Chung JH
- Cooper WA
- Dacic S
- Daigneault JB
- Ferrari-Light D
- Hirsch FR
- Hwang D
- Jain D
- Kerr KM
- Kunitoki K
- Lantuejoul S
- Lin D
- Longshore JW
- Lopez-Rios F
- Minami Y
- Mino-Kenudson M
- Moreira AL
- Motoi N
- Nicholson AG
- Noguchi M
- Ocampo PSS
- Papotti M
- Pass H
- Pelosi G
- Poleri C
- Rekhtman N
- Roden AC
- Russell PA
- Sholl LM
- Thunnissen E
- Travis WD
- Tsao MS
- Wistuba II
- Xia Y
- Yatabe Y
- Yoshida A
- Zhong H