Table 2.

Relevant randomized controlled trials in lung cancer chemoprevention highlighting differences between current and former smokers

TrialPopulationInterventionEndpointOutcome—current smokersOutcome—former smokers
ATBC, 1994 (18)Male current smokersα-Tocopherol, β-caroteneLung cancerIncrease in lung cancerN/A
CARET, Omenn et al., 1996 (32)Smokers (current or former)β-Carotene, retinol palmitateLung cancerIncrease in lung cancerTrend toward decrease in lung cancer
Lippman et al., 2001 (34)Following resection of stage I NSCLC13-cis-RASurvivalDecreased survivalTrend toward increased survivala
Kurie et al., 2003 (43), Hittelman et al., 2007 (117)Former smokers9-cis-RA or 13-cis-RA plus α-tocopherolRAR-β, Ki-67, and metaplasiaN/AIncrease in RAR-β and decrease in Ki-67
Mao et al., 2011 (45)Former smokersCelecoxibKi-67 labeling indexN/ADecrease in Ki-67
Keith et al., 2011 (47)Smokers (current or former)Oral iloprostEndobronchial dysplasiaNo histologic improvementImprovement in histology

Abbreviations: 9-cis-RA, 9-cis-retinoic acid; 13-cis-RA ATBC, 13-cis-retinoic acid; Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study; CARET, Carotene and Retinol Efficacy Trial; RAR-β, retinoic acid receptor-β.

aNonsmokers enrolled on this trial had a trend toward lower death rate with 13-cis-RA vs. placebo: 2% vs. 5.2%, P = 0.14.