I recently authored a post titled Another Reason to Not Use Sunscreen, in which discussed some research suggesting that the increased use of sunscreen is resulting in inadequate Vitamin D levels in populations around the world. In that post, I further stated that the data concerning skin cancer rates didn’t really support the use of sunscreens. Despite ever increasing SPFs, the rough quantification of a sunscreen’s protective capabilities, incidence of skin cancer hasn’t decreased, but is in fact on the rise.
This post can be considered a companion to my previous offering. Published in the Mayo Clinic Proceedings, Incidence and Trends of Basal Cell Carcinoma and Cutaneous Squamous Cell Carcinoma, reports that the incidences of both basal cell carcinomas (BCC) and cutaneous squamous cell carcinomas (cSCC) are increasing, and that there is a disproportionate increase in cSCC relative to BCC. For those who don’t recall, BCC is considered the least dangerous form of skin cancer and cSCC is considered more dangerous than BCC, but less dangerous than malignant melanoma, the most deadly form of skin cancer. Though not noted in this study, other studies confirm that rates of malignant melanoma are on the rise as well. The authors further noted a disproportionate increase in the incidence of both tumors in women, and a shift of anatomical distributions of skin cancers.
The study reviewed the medical records of a population diagnosed with nonmelanoma skin cancer between 2000 and 2010, and adjusted the incidence rates for both age and sex. The age- and sex-adjusted incidence rates were calculated and compared with estimates from previous periods. The authors reported diagnosed incidences of cSCC increased 263 percent, while BCC increased 145 percent. When biological sex is considered, women ages 30-49 experienced the greatest increase in BCC diagnoses, while women in two age groups, 40-59 and 70-79, experienced the greatest increase in cSCC.
Men had an increase in cSCCs between the first and second time period studied (1976-1984 and 1985-1992), but experienced a slight decline in the 2000-2010 period. However, for BCCs, men over 29 showed similar increases in diagnoses in the 2000-2010 period then the two earlier periods.
In addition to the increased rates of BCCs and cSCCs, the authors report that shifts in anatomical locations where the cancer tumors arise. In the earlier time periods studied, both BCCs and cSCCs were diagnosed more commonly on the head and neck. However, in the most recent time period studied, data show that BCC tumors on the torso increased, as did cSCCs on the extremities.
What does the studies author recommend? “Use sunscreen,” says Dr. Baum. “This includes on your left arm for those who do a lot of driving. UV rays can penetrate car windows and exposed skin ─ even when the sun isn’t shining. UV rays bounce around under the clouds, off the snow, buildings, and more, causing damage ─ even on gray days.”
Despite the study’s author’s conclusion and recommendations, I don’t see any good evidence to use sunscreen… or at least in excess. There’s something to be said for a radical transition, such as an extremely fair skinned individual such as myself who lives in the mountains going to the beach for a week or two. I do that every summer, and given the extreme nature of the change, I’m likely to use sunscreen, predominantly to avoid the pain of a horrible, blistering sunburn, but under most normal circumstances, I’m extremely unlikely to use it.