From CDC Preventing Chronic Disease Public Health Research, Practice, and Policy Volume 5: No. 4, October 2008

Br J Cancer. 2008 Mar 25 [Epub ahead of print]

Stein L, Urban MI, Weber M, Ruff P, Hale M, Donde B, Patel M, Sitas F.

1MRC/NHLS/Wits Cancer Epidemiology Research Group, National Health Laboratory Service, PO Box 1038, Johannesburg 2000, South Africa.

Abstract

Demographic and lifestyle information from 9690 black patients diagnosed with cancer or cardiovascular disease was collected in an ongoing case-control study in Johannesburg, South Africa. Compared to never smokers, the odds ratio (OR) for lung cancer among current smokers was 16.3 (95% confidence interval (CI), 9.6-27.6) for men and 6.4 (95% CI, 4.0-10.4) for women. The corresponding OR for other smoking-related cancers was 4.6 (95% CI, 3.7-5.7) among men and 1.9 (95% CI, 1.6-2.2) among women, and for cardiovascular disease, 3.4 (95% CI, 2.1-5.4) among men and 1.5 (95% CI, 1.1-2.1) among women. Risks were higher among smokers than former smokers, and all risk estimates increased with increasing levels of smoking duration and intensity. Non-electric domestic fuel was associated with approximately 60% increase in the risk of smoking-related cancer, but not cardiovascular disease. Risks for cancers of cervix, oesophagus, oral cavity/pharynx, stomach, larynx, pancreas and anogenital region, as well as squamous cell carcinoma of skin were all significantly higher among current than never-smokers, with ORs ranging from 1.5 for cervix (95% CI, 1.2-1.8) to 14.7 for larynx (95% CI, 7.2-30). The risks of tobacco-related disease reported here are similar to that currently observed in Western countries, even though cigarette consumption is relatively low in this population.

Prior studies have found that postmastectomy radiotherapy (PMRT) for breast cancer (BC) increases the risk of lung cancer (LC). We explored the joint effects of cigarette smoking and PMRT on LC risk.

We conducted a population-based nested case-control study among women registered in the Connecticut Tumor Registry diagnosed with nonmetastatic BC between January 1, 1965 and December 31, 1989. Patient cases developed a LC 10 years after BC diagnosis. Controls were matched to patient cases on age, year of BC diagnosis, and length of survival. Medical records were reviewed for pathology, BC therapy, and smoking history.

Among 113 second primary LC patient cases and 364 controls, compared with nonsmoking women who did not receive PMRT, nonsmoking women who received PMRT had no higher risk of LCPMRT after a diagnosis of BC sharply increased the risk of second primary LC, especially in the ipsilateral lung, among ever-smokers. Clinicians should consider including smoking history in their discussions with patients about the risks and benefits of PMRT.