Prognosis of metastatic carcinoma of the lung in the bevacizumab era: comparison between the major histologic types of lung cancer

Abstract

Background: In October 2006, bevacizumab was approved for treatment for patients with metastatic non-small-cell lung cancer other than squamous carcinoma. Our hypothesis was that the change in survival after approval of bevacizumab for metastatic adenocarcinoma would show differences from that of small-cell carcinoma and squamous carcinoma.

Methods: Data was obtained from the National Cancer Institute Surveillance Epidemiology and End Results (SEER) registry for patients with lung cancer diagnosed between January 2004 and November 2007. In addition to known characteristics predicting survival differences (histotype, age, gender, and race) we compared 1-year survival experience in those diagnosed before (January 2004-September 2006) and after (October 2006-November 2007) introduction of bevacizumab.

Results: Of 24,575 patients meeting criteria, 16,081 (65.4%) died within 1 y. Adjusted for age, gender, and race, patients with squamous carcinoma showed a 13% decline (95% CI 7%-20%) in survival times. By contrast, the 1% increment for adenocarcinoma and the 1% decrement for small cell carcinoma might well have been due to chance (P > 0.05 for each analysis).

Conclusions: Life expectancy for metastatic adenocarcinoma (for which bevacizumab is approved) and metastatic small-cell carcinoma (bevacizumab not approved) did not change statistically. On the other hand, life expectancy for patients with metastatic squamous carcinoma (bevacizumab not approved) of the lung has declined since the approval of bevacizumab. This likely reflects increased classification of tumors previously diagnosed as poorly differentiated non-small-cell carcinoma as poorly differentiated squamous carcinoma. Hence, life expectancy of metastatic adeno, squamous, and small-cell-lung cancer has not improved after introduction of bevacizumab.