Predicting Survival Outcomes for Nodal Staging of Lung Cancer

Using different lung staging methods, researchers examined 5-year survival outcomes in patients with non-small cell lung cancer (NSCLC) during a recent study.

Accurate mediastinal nodal staging is an imperative step in managing NSCLC, because it helps direct therapy and also has prognostic value.

In an analysis published in JAMA, researchers looked at the Assessment of Surgical Staging vs Endosonographic Ultrasound in Lung Cancer (ASTER) trial, which compared mediastinoscopy (surgical staging) with an endosonographic staging strategy, combining the use of endobronchial and transesophageal ultrasound followed by a mediastinoscopy, if negative. The ASTER trial revealed that the endosonographic strategy was significantly more sensitive for diagnosing mediastinal nodal metastases (94%) than surgical staging (79%).

For the current analysis, researchers evaluated the survival of patients in the ASTER trial. Of the 241 patients with potentially resectable NSCLC, 123 patients were randomized to have endosonographic staging, and 118 patients were randomized for surgical staging in 4 tertiary referral centers.

Researchers obtained the survival data through death registries, patient records, or contact with general practitioners. They were able to obtain 5-year survival data from 237 of 241 patients. The results of the analysis showed that 54% of patients had a prevalence of mediastinal nodal metastases in the endosonographic strategy group, compared with 44% in the surgical strategy group.

Survival at 5 years in the endosonographic strategy group was 35%, versus 35% for the surgical strategy. The estimated median survival was 31 months for endosonographic and 33 months for the surgical strategy.

“Why did improved mediastinal staging not lead to improved survival? Missing data occurred in less than 2% and therefore are an unlikely source of bias,” study authors wrote. “However, ASTER was powered to detect a difference in diagnostic sensitivity, not survival, as reflected by the wide confidence intervals. If a survival difference between the strategies exists, it is likely to be small and a larger sample size may be needed to detect it. However, randomized trials to detect a survival difference based on staging strategy are not likely to be conducted as the endosonographic strategy is now advised in clinical guidelines.”