294 / 1498
RR non/light smokers
RR smokers
No RT (< 5 Gy), no CT
RT (
≥
5 Gy), no CT
No RT (< 5 Gy), CT
RT (
≥
5 Gy), CT
1.0 (ref)
7.2 (2.9-21.2)
4.3 (1.8-11.7)
7.2 (2.8-21.6)
6.0 (1.9-20.4)
20.2 (6.8-68)
16.8 (6.2-53)
49.1 (15.1-187)
•
Smoking is the major cause of lung cancer
(only 7 out of 222 cases were never smokers)
•
Risks from smoking multiply risks from treatment
Joint effects of smoking and treatment
Nested case-control study: 222 cases of lung cancer, 444 matched controls