How serious is squamous cell carcinoma?

Dear Cecil: I’m 48 years old. A few months ago, a small growth appeared on the upper side of my left forearm. It looked like a wart, but I went to a doctor recently and had it excised and biopsied. It was a squamous cell carcinoma. The doctor told me there was almost nothing to worry about since squamous cell is one of the least dangerous forms of cancer. Still, it’s hard not to stress about this. I trust your always excellent feedback. What is a squamous cell carcinoma? Do they metastasize at predictable rates? How much do I really have to worry about? If it makes any difference, I smoked cigarettes off and on for 30 years, but quit for good 14 months ago Neil Flowers, Santa Cruz

Cecil replies:

Nothing like cancer to make an aging baby boomer realize he’s not a kid anymore. Not to argue with your doctor, but “least dangerous” is not a term I would apply to squamous cell carcinoma. It is much less dangerous than some cancers, but it can spread and it can kill you. What’s more, if you’ve had it once, there is significantly increased risk that you will get it again. See a doctor immediately about any new growths. Also, while the damage has probably already been done, I’d skip any future sunbathing — squamous cell carcinoma appears to be directly related to solar exposure.

Skin cancer in general is extremely common, accounting for a quarter to a third of all cancers. New cases appear to be increasing rapidly, perhaps because of the thinning ozone layer; some call it an epidemic. There are three main types: basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell is the most common by far, with more than 500,000 new cases a year. It’s also the least dangerous. Basal cell carcinomas grow slowly and seldom spread; deaths are rare. Squamous cell carcinoma also occurs fairly frequently, with about 100,000 new cases per year, but the prognosis isn’t as bright; this type of cancer kills about 2,000 people a year. Still, it’s a lot less serious than melanoma, the most dangerous of all skin cancers. About 32,000 new melanomas are reported each year; 6,500 of this number will die of it.

Diagnosing skin cancer is something you want to leave to the pros, but in general basal cell carcinomas are smooth while the squamous cell kind have a sandpapery feel (squamous means scaly). Melanomas typically affect pigmented areas such as moles and birthmarks. Squamous cancers usually show up in areas most exposed to the sun such as the head, neck, and the back of the hands and forearms, often on sun-damaged skin (roughened, wrinkled, discolored, etc.). Light-skinned people are more vulnerable than dark; men get them twice as often as women.

The cure rate for S-C carcinomas is on the order of 90 percent — not an entirely comforting figure. The thinner and smaller the tumor, the better the odds it won’t recur. One study reported a 99.5 percent cure rate for growths less than one centimeter in diameter but only 59 percent for those larger than three centimeters, a compelling argument for not procrastinating if you’ve got some suspicious bumps.

Your smoking probably had little to do with your carcinoma. The real culprit was baking on the beach when you were a kid. One study concluded that using an SPF 15 sunscreen till age 18 could reduce the number of nonmelanoma skin cancers 78 percent. Never-tan, always-burn types would be smart to use SPF 25 to 30, and what the hell, a big umbrella and a muumuu might not be such a bad idea either. Better a little dorkiness now than a biopsy later.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.