Study Compares Survival Outcomes Using Different Cancer Staging Methods

Accurate mediastinal nodal staging directs therapy, and provides prognostic value during the management of Non-Small Cell Lung Cancer (NSCLC).

The Assessment of Surgical Staging vs Endosonographic Ultrasound in Lung Cancer (ASTER) trial compared an endosonographic staging strategy with surgical staging using mediastinoscopy. Endosonography combines endobronchial, and transesophageal ultrasound, and is followed up using mediastinoscopy, in case the results are negative.

The researchers evaluated 241 patients suffering from potentially resectable NSCLC, in 4 tertiary referral centers. There were 123 patients randomized to endosonographic staging, and 118 patients to surgical staging. The researchers found that endosonography was significantly more sensitive (97%) during the diagnosis of mediastinal nodal metastases, compared to surgical staging (79%).

The five-year survival rate was 35% for both the endosonographic and surgical strategies. The estimated median survival for the endosonographic strategy was 31 months compared to 33 months for the surgical strategy. The researchers concluded that improved mediastinal staging could ensure better treatment for a larger number of patients, and could increase the long-term survival rates of the patients.

Jouke T. Annema, MD, PhD, Academic Medical Center, Amsterdam (Amsterdam, Netherlands), said, "Why did improved mediastinal staging not lead to improved survival? Missing data occurred in less than 2 percent and therefore are an unlikely source of bias. 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."

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