Posted by Larry Hoover on December 14, 2003, at 9:46:36
In reply to Selenium may raise skin cancer risk ?, posted by McPac on December 14, 2003, at 1:54:29
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> Selenium may raise skin cancer risk
> Last Updated: 2003-10-01 15:41:54 -0400 (Reuters Health)
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> NEW YORK (Reuters Health) - In patients with a history of skin cancer other than melanoma, the use of selenium supplements does not appear to prevent the recurrence of two other types of skin cancer--basal cell and squamous cell cancer--and may actually raise the risk of squamous cell cancer, new research suggests.I'd have to read the subject selection criteria and some other methodological factors, to really get into the nitty-gritty of this study, but....
1. All subjects already had a history of skin cancer. Generalization to people without a history of skin cancer is not reasonable.
2. The increased incidence was really quite modest (relative risk 1.25), but they didn't put the absolute incidence in the abstract, so it's hard to say what that increased risk translates into in terms of new cancers.
3. I see no obvious evidence that they looked at any other antioxidant systems in conjunction with selenium supps; vitamins C and E work in interaction with other antioxidants, and manipulating just one variable may give a distorted response.
4. The study had previously found non-significant increases in cancer recurrences (in the study period of 1983-1993), while increasing the followup period by three years (to 1996) produced the statistically significant differences between placebo and selenium supp groups. That's not a very dramatic finding.
Quite frankly, other than making good press, I don't quite see the how this study tells us very much about nonmelanoma skin cancer. The single best thing for anyone to do is to self-monitor, and report any skin lesions to a medical professional for assessment. Squamous cell skin cancer is easily treated, when treated early in the development of the lesions.
Just my opinionated two cents (or so),
LarHere's the abstract:
J Natl Cancer Inst. 2003 Oct 1;95(19):1477-81.
Selenium supplementation and secondary prevention of nonmelanoma skin cancer in a randomized trial.Duffield-Lillico AJ, Slate EH, Reid ME, Turnbull BW, Wilkins PA, Combs GF Jr, Park HK, Gross EG, Graham GF, Stratton MS, Marshall JR, Clark LC; Nutritional Prevention of Cancer Study Group.
Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
The Nutritional Prevention of Cancer Trial was a double-blind, randomized, placebo-controlled clinical trial designed to test whether selenium as selenized yeast (200 microg daily) could prevent nonmelanoma skin cancer among 1312 patients from the Eastern United States who had previously had this disease. Results from September 15, 1983, through December 31, 1993, showed no association between treatment and the incidence of basal and squamous cell carcinomas of the skin. This report summarizes the entire blinded treatment period, which ended on January 31, 1996. The association between treatment and time to first nonmelanoma skin cancer diagnosis and between treatment and time to multiple skin tumors overall and within subgroups, defined by baseline characteristics, was evaluated. Although results through the entire blinded period continued to show that selenium supplementation was not statistically significantly associated with the risk of basal cell carcinoma (hazard ratio [HR] = 1.09, 95% confidence interval [CI] = 0.94 to 1.26), selenium supplementation was associated with statistically significantly elevated risk of squamous cell carcinoma (HR = 1.25, 95% CI = 1.03 to 1.51) and of total nonmelanoma skin cancer (HR = 1.17, 95% CI = 1.02 to 1.34). Results from the Nutritional Prevention of Cancer Trial conducted among individuals at high risk of nonmelanoma skin cancer continue to demonstrate that selenium supplementation is ineffective at preventing basal cell carcinoma and that it increases the risk of squamous cell carcinoma and total nonmelanoma skin cancer.
poster:Larry Hoover
thread:289557
URL: http://www.dr-bob.org/babble/alter/20031204/msgs/289599.html