Squamous cell carcinoma is on the rise: incidence of basal cell carcinoma is also increasing; both types affect men more than women. UV exposure is said to be the cause.
The World Health Organization estimates that two to three million nonmelanoma skin cancers occur worldwide every year. In the U.S., estimates suggest that between 186, 157 and 700,000 cutaneous squamous cell carcinomas (cSCC) are diagnosed annually.
A recent study, conducted from 2000 to 2010 and published in Mayo Clinic Proceedings online, May 15, 2017, found that cutaneous squamous cell carcinoma (cSCC) increased by 263 percent in the time between an earlier study from 1976 to 1984 and the recent study, while basal cell carcinoma (BCC) increased 145 percent in the same time period. Men had greater increases than women in both SCC and BCC.
The study also found that carcinomas had shifted location over time, with BCC moving from the head and neck to the torso and cSCC shifting from the head and neck to the extremities. The study was conducted in Olmsted County, MN (see sidebar, Page 2), which has a long history of collaboration with the Mayo Clinic and the National Institutes of Health.
Previous studies for both types of carcinomas were conducted in 1976-1984 (Journal of the American Academy of Dermatology, 1990) and 1984 to 1992 (Archives of Dermatology, 1997).
Carcinoma Location. In both sexes, the most common cSCC location was the head and neck, with the extremities the second most common. The proportion of cSCC tumors on the extremities increased in men (24.4 vs 12.5 percent in 2000-2010 vs. 1976-1984 and in women (38.1 vs. 17.1 percent). The torso was the least likely cSCC location, but a higher number of BCCs were found on the torso during the more recent period than the previous study period (men, 24.4 and 10.7 percent, women, 23.6 vs. 10.6 percent).
Trends in occurrence and anatomical location may reflect an increase in recreational ultraviolet exposure--tanning habits--which increase the intermittently intense and cumulative UV exposures, researchers say.
Treatment. Standard treatment for small or superficial low-risk BCCs and SCCs on the abdomen, chest, back, arms and legs consists of cryosurgery (freezing), surgical excision, curettage and electrodesiccation (scraping and burning), photodynamic therapy and topical medications.
For more complicated carcinomas, Mohs surgery is viewed as the single most effective technique for removing BCCs and SCCs, particularly for cancers in the head and neck region.
Mohs is done in stages; using a scalpel, the doctor removes the thinnest possible layer of visible cancerous tissue. Lab work is done immediately on site. The tissue is frozen, stained, then examined under a microscope. If cancer cells remain, the procedure starts all over again until a cancer-free layer is reached.
Prevention. The rules of prevention haven't changed much: Use sunscreen at all times, even on gray days (UV rays still abound), wear a wide-brim hat and coverup clothing when outdoors, try to stay out of the sun between 10 a.m. and 4 p.m., and see your dermatologist annually (more frequently if you have a history of skin cancers) for a full-body checkup.
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|Publication:||Duke Medicine Health News|
|Date:||Aug 1, 2017|
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