ATLANTAUse of adjuvant chemotherapy for stage IB non-small-cell lung cancer (NSCLC) is less certain than it appeared to be at last year's American Society of Clinical Oncology (ASCO) meeting, according to a study reported at the 2006 ASCO Annual Meeting. A second study showed that adjuvant chemotherapy is effective for stage II-III NSCLC and that vinorelbine (Navelbine)/ cisplatin may be better than other doublets. A third study showed that vinorelbine/cisplatin is effective for elderly patients.
CALGB 9633 Update
Gary M. Strauss, MD, MPH, reported updated data from the Cancer and Leukemia Group B (CALGB) 9633 study of adjuvant chemotherapy in stage IB NSCLC (abstract 7007). Preliminary results of that trial reported in 2004 showed significantly better disease-free survival (DFS) and overall survival (OS) with adjuvant carboplatin and paclitaxel. Dr. Strauss said that the study was initially planned to accrue 500 patients but due to the interim analysis and slow accrual, the accrual target was reduced to 384.
Patients were randomized following resection to paclitaxel 200 mg/m2 and carboplatin AUC 6 every 3 weeks for four cycles or to observation. The primary endpoint was overall survival. Dr. Strauss reported data for 344 patients included in the intent-to-treat analysis. Median follow-up was 57 months, and mean tumor size was 4.5 cm.
Overall survival was significantly better with adjuvant chemotherapy for only a limited time (see Table 1). The hazard ratio (HR) for median OS was a nonsignificant 0.80. Median failure-free survival (FFS) was significantly better with adjuvant chemotherapy (HR 0.74, P = .03), although by year, the advantage was significant only at year 3 (see Table 2).
Dr. Strauss said that early stopping decisions in clinical trials are potentially problematic because early indications of treatment effectiveness may decline over time. He pointed out that, due to the small number of patients, this study wound up with only a 40% power to show a significant survival difference.