by ecancer reporter Janet Fricker

Women who have squamous cell skin cancers (SCC) are more likely to have smoked than women who are free from the disease, finds a study published in “Cancer Causes Control”. The study, however, observed no such association with basal cell carcinoma (BCC) among women who smoke; while for men smoking was modestly associated with both SCC and BCC.

Non-melanoma skin cancer (NMSC), comprised of  SCC and BCC , is the most frequently occurring cancer among Caucasians in the US. While BCC and SCC are often studied as one disease entity, increasingly it is being recognised that  risk factors can differ.

 Dana E. Rollison and colleagues, from the Department of Cancer Epidemiology at Moffitt Cancer Center ,  conducted a clinic-based case-control study where the smoking habits of 383 patients diagnosed with a histologically confirmed basal or squamous cell carcinoma  between March 2007 and December 2008 were compared to 315 controls found to be disease free when they underwent skin cancer screening at the same clinic. Information on how much participants  smoked,  and when they started was  obtained from self-administered questionnaires.

Results showed that among women, smoking for 20 pack years or more was associated with a significant three-fold risk of SCC (ORR=3.00, 95%  CI=1.02-8.80), but showed no association with BCC (OR=0.98, 95% CI=1.02-8.80). Among men, smoking for 20 pack years or more was associated with non significant increased risks of BCC (OR=1.90, 95% CI 0.88-4.12) and SCC (OR=1.97, 95% CI =0.84-4.66).

Overall smoking was statistically significantly associated with SCC (OR=1.97, 95% CI=1.19-3.26), with

significant trends associated with increasing cigarettes per day (p = 0.01) and pack-years

smoked (p = 0.01).

Analyses conducted to tease apart the independent effects of duration and dose, they add,  suggested that years smoked was more strongly associated with NMSC than cigarettes smoked per day.

Observations from the lung cancer literature, suggest the authors, may provide explanations for the observed gender differences in smoking-associated SCC. Women have been shown to have more active CYP enzyme activity in the lungs responsible for metabolizing nicotine, possibly due to upregulation of CYP by oestrogen and also to have lower levels of DNA repair capacity enzymes.

 “Additional studies are needed to further characterize these gender differences in smoking-associated NMSC,” conclude the investigators. .

Reference

D.E. Rollison, M.R. Iannacone,  J.L. Messina, et al. Cancer Causes Control. Case-control study of smoking and non-melanoma skin cancer.  Cancer Causes Control. DOI: 10.1007/s10552-011-9872-Y