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Keywords:

  • non–small cell lung cancer;
  • survival;
  • first-line chemotherapy;
  • platinum-doublet;
  • propensity score analysis;
  • SEER-Medicare

BACKGROUND

Randomized trials report equivalent efficacy among various combinations of platinum-based regimens in advanced non–small cell lung cancer (NSCLC). Their relative effectiveness and comparability based on squamous versus nonsquamous histology is uncertain.

METHODS

The authors used the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data to identify first-line chemotherapy agents administered to Medicare beneficiaries with stage IIIB or IV NSCLC diagnosed from 2000 to 2007. Overall survival was compared between patients who received the 3 most common regimens: carboplatin-paclitaxel, carboplatin-gemcitabine, and carboplatin-docetaxel. Stratified analyses distinguished between the outcomes of patients with squamous versus nonsquamous cell histology. Multivariable Cox proportional hazards models and propensity score analyses facilitated adjustment for imbalance in measurable patient characteristics.

RESULTS

Of the 15,318 patients who received first-line chemotherapy, 43.1% received carboplatin-paclitaxel, 14.3% received carboplatin-gemcitabine, 8.5% received carboplatin-docetaxel, and 34.1% received other regimens. The median survival was 8.0 months (interquartile range [IQR], 3.5-17.4 months) for carboplatin-paclitaxel, 7.3 months (IQR, 3.4-15.2 months) for carboplatin-gemcitabine, and 7.5 months (IQR, 3.2-16.0 months) for carboplatin-docetaxel. Both multivariable and propensity score-adjusted Cox models demonstrated a slight inferiority associated with carboplatin-gemcitabine or carboplatin-docetaxel versus carboplatin-paclitaxel, with a hazard ratio of 1.10 (95% confidence interval, 1.04-1.15) and 1.09 (95% confidence interval, 1.02-1.16), respectively, in propensity score-stratified models. Among the subgroup of 2063 patients with squamous carcinoma, propensity score-stratified analyses had a higher risk of death (hazard ratio, 1.20; 95% confidence interval, 1.07-1.35) associated with carboplatin-gemcitabine versus carboplatin-paclitaxel.

CONCLUSIONS

Carboplatin-paclitaxel was associated with slightly better survival compared with carboplatin-gemcitabine or carboplatin-docetaxel within the Medicare population with advanced NSCLC, and this was most pronounced for patients who had squamous cell histology. Cancer 2013;119:2048–2060. © 2013 American Cancer Society.