No Difference in Survival Rates in Patients With Lung Adenocarcinoma In Situ vs Minimally Invasive Adenocarcinoma
Lung cancer patients with minimally invasive adenocarcinoma have similar, positive 5-year disease-free survival and overall survival rates as patients with adenocarcinoma in situ, according to research presented today at the 2014 Chicago Multidisciplinary Symposium in Thoracic Oncology (Abstract 104).
Lung adenocarcinoma accounts for 60% of all non–small cell lung cancers and is the most common form of lung cancer in smokers, nonsmokers, and patients younger than 45 years old. Bronchioloalveolar carcinoma is a type of adenocarcinoma that affects the cells lining the alveoli of the lungs. Invasion occurs when the tumor extends beyond the alveolar lining and evokes a fibroblastic stromal response. These types of tumors, if ≤ 3 cm in size, are reclassified as adenocarcinoma in situ (no tumor invasion) or minimally invasive adenocarcinoma (≤ 0.5 cm of tumor invasion), according to the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) International Multidisciplinary Classification of Lung Adenocarcinoma.
This study examined the difference in disease-free survival and overall survival rates for patients with diseases classified as adenocarcinoma in situ and minimally invasive adenocarcinoma and determined if it is beneficial to categorize tumors according to additional subtypes.
Study Details
The study authors conducted a comprehensive search of studies published from 2011 to 2014 in the MEDLINE®, Embase, and Cochrane databases. Studies selected for analysis provided survival outcome data for at least eight cases classified as adenocarcinoma in situ or minimally invasive adenocarcinoma based on the 2011 IASLC/ATS/ERS classification. Excluded studies did not report survival information. A systematic analysis of disease-free survival and overall survival data was performed using the random effect model of the Comprehensive Meta Analysis (Version 2.2) software.
The study’s analysis included information from 18 clinical studies published from 2011 and 2014. The 18 studies included a total of 863 patients, with 451 patients classified as adenocarcinoma in situ and 344 patients classified as minimally invasive adenocarcinoma. One study reported survival data on patients (68) with adenocarcinoma in situ and minimally invasive adenocarcinoma grouped together. The median age of all patients was 67.5 years old. Sixty-one percent (526) of patients were female, and 43% (371) of all patients were smokers. The median tumor size was 1.3 cm.
The 5-year disease-free survival and overall survival rates were not statistically different between patients with adenocarcinoma in situ and minimally invasive adenocarcinoma. The 5-year disease-free survival rate was 97.7% for all patients included in the analysis. The 5-year disease-free survival rate was 97% in patients with adenocarcinoma in situ and 96.7% in patients with minimally invasive adenocarcinoma (P = .34). The 5-year overall survival rate was 97.3% for all patients included in the analysis. The 5-year overall survival rate was 97.5% in patients with adenocarcinoma in situ and 96% in patients with minimally invasive adenocarcinoma (P = .58).
Questions Raised About Tumor Subclassification
“Some researchers have advocated that adenocarcinoma in situ and minimally invasive adenocarcinoma should have separate categorization,” said lead author Madhusmita Behera, PhD, Associate Director of Research in the Department of Hematology and Medical Oncology at Winship Cancer Institute of Emory University in Atlanta. “Our analysis demonstrates that these carcinomas, especially when the tumor is 3 cm or less in size, are associated with excellent survival outcomes; therefore, tumor subclassification into adenocarcinoma in situ and minimally invasive adenocarcinoma may not provide additional prognostic information.”
The Symposium is sponsored by the American Society of Clinical Oncology (ASCO), the American Society for Radiation Oncology (ASTRO), IASLC, and The University of Chicago Medicine.
The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
