Gender effect in the ITALUNG screening trial. A comparison with UKLS and other trials

The existence of gender differences in the efficacy of lung cancer (LC) screening with low dose CT is an inter- esting issue. In the meta-analysis associated with the mortality results of the UKLS trial, larger reductions of LC mortality were observed in females in the NELSON, NLST and LUSI trials, but not in the UKLS. 1 ITALUNG trial is a small size study that recruited 1132 women and 2074 men who were younger and predominantly cur- rent smokers as compared to those in UKLS, 2 and reported a 30% reduction of LC mortality in the active group. 3 After a follow-up extension of two years, the decreased LC mortality was 24%. 4 Herein we report gender effect in the ITALUNG extended follow-up data- set. Females showed a more pronounced LC mortality reduction (10 LC deaths during 6419 person-years in the active group and 16 LC deaths during 6076 person- years in the control group, resulting in a rate ratio of 0.59; 95%CI:0.27-1.30) than males (48 LC deaths dur- ing 11168 person-years in the active group and 58 LC deaths during 10975 person-years in the control group, resulting in a rate ratio of 0.81; 95%CI:0.56-1.19). The more pronounced benefit of LC screening in women was non statistically significant (p=0.477). Reasons underlying the greater LC reduction in females partici- pating to LC screening are unclear. Women have LC with a longer preclinical sojourn time, especially in case of adenocarcinoma, that would favour the possibility of screening detection. 5 Women might also be in healthier general conditions and have less co-morbidities.