Severe Sunburn as the Overwhelming Risk Factor for 3 Common Skin Cancers: New Prevention Strategy

Re-analysis of published data from two large prospective cohort studies by Wu, et al., probably provides the hitherto most unequivocal evidence that Severe Sunburn (SS) was an overwhelming risk factor (>90%) for all incidences of melanoma, Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) in both men and women. It is found, for example, that experiencing 1-5 and ≥ 6 SSs increased one’s risk for melanoma in men by 12.7-fold and 22fold, respectively. Since use of sunscreen during intense intermittent sun exposure can cause unintended SS, a false security phenomenon, sunscreen can be postulated as a potential major risk factor for causing skin cancers. Because chronic exposure to non-burning sunlight is protective against melanoma and can enhance immunity, this protective effect may also likely occur with less serious BCC and SCC. Therefore, regular exposure to non-burning sunlight may serve as a new strategy for skin cancer prevention and general health promotion. It is theorized that in addition to immunity enhancement, regular exposure to non-burning sunlight can result in skin tanning that will protect against sunburn and thereby protect against skin cancer. The role of erythema, a mild sunburn, in cancer incidences may be relatively limited. Since skin aging in ordinary people may be predominantly caused by the intrinsic factor, and SS is predominantly caused by intense ultraviolet (UV) B rays, the need of using broadspectrum sunscreens or organic sunscreen ingredients for protection against UVA may need to be re-considered.