Antioxidants not skin cancer risk and dermatologists better at finding cancer than you
Posted Aug 17 2009 10:56pm
Two articles coming out today regarding skin cancer.
The first one shows that antioxidant supplements do not appear to be associated with an increased risk of melanoma, according to a report in the August issue of Archives of Dermatology.
A recent randomized trial of antioxidants for cancer prevention found that daily supplementation with nutritionally appropriate doses of vitamins C and E, beta carotene, selenium and zinc appeared to increase the risk of melanoma in women four-fold. Because an estimated 48 percent to 55 percent of U.S. adults use vitamin or mineral supplements regularly, the potential harmful effects of these nutrients is alarming, the authors note.
Maryam M. Asgari, M.D., M.P.H., and colleagues examined the association between antioxidants and melanoma among 69,671 women and men who were participating in the Vitamins and Lifestyle (VITAL) study, designed to examine supplement use and cancer risk. At the beginning of the study, between 2000 and 2002, participants completed a 24-page questionnaire about lifestyle factors, health history, diet, supplement use and other cancer risk factors.
Intake of multivitamins and supplements during the previous 10 years, including selenium and beta carotene, was not associated with melanoma risk in either women or men. The researchers also examined the risk of melanoma associated with long-term use of supplemental beta carotene and selenium at doses comparable to the previous study and found no association. ( Arch Dermatol. 2009;145:879-882.)
The second study found that dermatologists are better at finding cancers earlier than patients. Most melanomas detected in a general-practice dermatology clinic were found by dermatologists during full-body skin examinations of patients who had come to the clinic for different complaints, according to a report in the August issue of Archives of Dermatology. In addition, cancers detected by dermatologists were thinner and more likely to be in situ (only on the outer layer of skin) than were cancers detected by patients.
Jonathan Kantor, M.D., M.S.C.E., and Deborah E. Kantor, M.S.N., C.R.N.P., analyzed 126 cases of melanoma diagnosed at the practice between July 2005 and October 2008. Of these, 51 cases were invasive (had spread to deeper layers of the skin) and 75 were in situ.
Overall, 56.3 percent of all melanomas and 60 percent of melanomas in situ were detected by the dermatologists and were not among the reasons the patient had visited the clinic. Dermatologist detection was also associated with thinner melanomas. Patients whose melanoma was detected by a clinician were significantly more likely to have cancers thinner than 1 millimeter.
“These data suggest that minimizing the substantial public health and financial impact of melanoma may be aided by a full-body skin examination. While self-examination plays a critical role in early detection, prior studies have suggested that physicians, and dermatologists in particular, may be better able to detect melanomas with lesser tumor thickness.
Because increasing tumor thickness is closely correlated with decreasing survival, it follows that complete examination plays an important role, particularly in high-risk populations,” the authors write.
“Further research in this area, and in the cost-effectiveness of screening, may lead to important changes in practice that could potentially reduce melanoma mortality and improve patient outcomes,” they conclude.