Adjuvant Chemotherapy Can Improve Survival in Early Stage NSCLC

Although adjuvant chemotherapy has been found to improve survival in stage II and stage III non-small cell lung cancer (NSCLC) patients who have undergone complete resection, the evidence was lacking in early stage (stage I) patients. Now, a new study, published in the Journal of Thoracic Oncology, has found that chemotherapy administered in patients with stage I disease (tumors between 3 and 7 cm), following a complete resection, can have a significant impact on their median 5-year overall survival (OS).

Researchers from the Washington University School of Medicine in St. Louis conducted a retrospective analysis on nearly 30,000 patients who were diagnosed with T2N0M0 NSCLC between 2004 and 2011, according to the National Cancer Database. These patients had undergone complete resection and some of them (about 20%) had subsequently received adjuvant chemotherapy. Patients who died within 30 days of the surgery were excluded from the analysis. Each of the 2 cohorts (chemotherapy or not) were further classified into 4 groups based on tumor size:

• 3.1 to 3.9 cm
• 4.0 to 4.9 cm
• 5.0 to 5.9 cm
• 6.0 to 7.0 cm

The analysis found an improved median OS and 5-year OS in patients who were treated with a chemotherapy agent post surgery, compared with those who were not. By univariate analysis, the authors found that the 5-year OS for patients not receiving adjuvant chemotherapy was inversely related to tumor size, decreasing from 58% in patients with tumors between 3.0 and 3.9 cm in size, to 46.9% in those with tumors between 6.0 and 7.0 cm in size. However, in patients that received adjuvant chemotherapy, 5-year OS was nearly identical across the groups. Further, all patients receiving adjuvant chemotherapy, regardless of tumor size, showed improved median OS (95.6 vs 67.0 months; HR, 0.64; 95% CI, 0.61-0.68, P<.0001) and 5-year OS (67.9% vs 54.6%, P<.0001) when compared with the observation group.

The authors conclude that adjuvant chemotherapy in patients with completely resected T2N0M0 NSCLC improves survival independent of tumor size. Considering that tumors smaller than 4 cm in size currently are an exclusion criteria for trials of adjuvant chemotherapy treatment, the authors hope their study results will result in protocol amendments.

The 2 major limitations of their study, the authors highlight, are the retrospective nature of the analysis, and selection bias resulting from choosing patients who had to survive long enough to have the treatment administered.

Reference

Morgensztern D, Du L, Waqar SN, et al. Adjuvant chemotherapy for patients with T2N0M0 non-small-cell lung cancer (NSCLC) [published online June 8, 2016]. J Thorac Oncol. doi:10.1016/j.jtho.2016.05.022.