Radiographically determined noninvasive adenocarcinoma of the lung: Survival outcomes of Japan Clinical Oncology Group 0201

Objective: The study objective was to evaluate the long-term survival of patients with radiographically determined noninvasive lung adenocarcinomas. Methods: A prospective, multi-institutional study on image diagnosis to define early (noninvasive) adenocarcinomas of the lung (Japan Clinical Oncology Group 0201) has shown that a consolidation/tumor ratio on thin-section computed tomography 0.25 or less in cT1a (≤2.0 cm) could be used as a better radiologic criterion for a noninvasive pathology than a consolidation/tumor ratio 0.50 or less in cT1a-b (≤3.0 cm). From the prognostic viewpoints, these criteria were evaluated for 545 patients with adenocarcinoma who underwent lobectomy and lymph node dissection. Results: The subjects consisted of 233 men and 312 women with a median age of 62 years. The median follow-up period among overall patients was 7.1 years (range, 0-8.5 years). The overall and relapse-free 5-year survivals of the overall patients were 90.6% and 84.7%, respectively. When a consolidation/tumor ratio 0.5 or less in cT1a-b was used as a cutoff, the 5-year overall survivals of radiologic noninvasive (121 patients, 22.2%) and invasive (424 patients, 77.8%) adenocarcinomas were 96.7% and 88.9%, respectively, and the difference was statistically significant (P <.001, log-rank test). With the use of a consolidation/tumor ratio 0.25 or less in cT1a, the 5-year overall survivals of radiologic noninvasive (35 patients, 12.1%) and invasive (254 patients, 87.9%) adenocarcinomas were 97.1% and 92.4%, respectively, and the difference was not statistically significant (P =.259). Conclusions: The radiologic criteria of a consolidation/tumor ratio 0.25 or less in cT1a (≤2.0 cm) and 0.50 in cT1a-b (≤3.0 cm) were both able to define a homogeneous group of patients with an excellent prognosis before surgery.