皮肤癌，特别是基底细胞癌（Basal cell carcinoma）并不少见，仅在美国每年就有近100万基底细胞癌的新发病例。最近，有学者分析了饮用咖啡是否能够降低人们患皮肤癌之可能性？结果令人鼓励，即经常饮用咖啡确实具有预防皮肤基底细胞癌的功效。进一步分析发现，每天饮用咖啡越多（3杯或更多咖啡）者，其患皮肤基底细胞癌之风险就越低，但饮用咖啡并不能够预防皮肤鳞状上皮细胞癌（squamous cell carcinoma）和黑色素瘤（melanoma）。上述结论源于研究人员对近12万研究对象进行为期20余年随访所获得的资料分析，在随访过程中共有25000多人被发现患有皮肤癌，其中基底细胞癌最为常见（23000例），鳞状上皮细胞癌次之（2000例），黑色素瘤最少（741例）。

Daily Coffee May Lower Your Skin Cancer Risk

Researchers find association between caffeine consumption, basal cell carcinoma

MONDAY, Oct. 24 (HealthDay News) -- Your morning coffee might do more than jump-start your day. Researchers say that daily caffeine jolt might also reduce your risk of developing a type of skin cancer.

Basal cell carcinoma is the most common form of skin cancer, with nearly one million new cases diagnosed each year in the United States. A diet that contains even a small protective factor may have great public health impact, the researchers said.

"Our study indicates that coffee consumption may be an important option to help prevent basal cell carcinoma," said lead researcher Fengju Song, a postdoctoral fellow in the department of dermatology at Brigham and Women's Hospital and Harvard Medical School in Boston.

"The amount of caffeine consumption was inversely associated with risk," Song said, meaning the more coffee consumed, the lower the risk of skin cancer.

The study could not prove cause-and-effect, however, and at this point the finding remains an association only.

Decaffeinated coffee was not associated with a decreased risk of basal cell carcinoma, and the researchers said any protective effect would likely be because of caffeine, a stimulant. The study authors also expressed surprise that coffee did not reduce the risk of two other types of skin cancer, squamous cell carcinoma and the less common but potentially deadly melanoma.

Earlier experiments in mice found caffeine helped reduce the development of squamous cell carcinoma by eliminating cells damaged by ultraviolet radiation, but that effect was not seen in the current study.

The results were scheduled for presentation Monday at an American Association for Cancer Research International Conference in Boston.

For the study, Song's team collected data on nearly 113,000 adults -- almost 73,000 women who took part in the U.S. Nurses' Health Study and almost 40,000 men who were 　　part of the Health Professionals Follow-Up Study.

Over more than 20 years of follow-up, more than 25,000 cases of skin cancer were diagnosed among the men and women in the studies. Of these, about 23,000 were basal cell carcinoma, about 2,000 were squamous cell cancer and 741 were melanoma.

The researchers found that women who drank more than three cups of coffee a day had a 20 percent lower risk of developing basal cell carcinoma compared with women who drank less than one cup of coffee in a month.

For men, the risk was 9 percent lower for those who drank three cups of java daily compared with those who drank less than one cup a month, Song's group noted.

The risk for women who drank the most coffee was lowered 18 percent; for men who downed the most coffee, the risk was reduced 13 percent, Song's team found.

Additional studies exploring the mechanism behind this association are needed, Song said. People who spend a lot of time in the sun are more likely than others to develop skin cancer, but coffee's role in prevention is still not understood.

Dr. Robert S. Kirsner, professor and vice chairman of dermatology and cutaneous surgery at the University of Miami Miller School of Medicine, said the findings "could open a new avenue of developing chemo-prevention for non-melanoma skin cancer."

However, Kirsner doesn't advise starting to drink coffee solely to prevent skin cancer.

Although basal cell carcinoma is rarely fatal, there may be consequences of treatment, including disfigurement, especially if it is ignored, he said.

Because it is so common, the cost of treating basal cell carcinomas is "huge," he added. Prevention would affect overall health funding.

Also, some evidence suggests that having one type of skin cancer makes other cancers more likely, Kirsner said. "The obvious ones are other skin cancers, but also non-skin cancers, for example, lymphoma or testicular cancer.

"The question is, is this just by chance, or is it a shared risk factor, or is it something basal cell carcinoma induces that makes it more likely for those cancers to develop?" he said.

"Preventing a basal cell carcinoma may have other benefits than just preventing that cancer," Kirsner added.

Research presented at meetings should be considered preliminary until published in a peer-reviewed medical journal.

SOURCES: Fengju Song, Ph.D., postdoctoral fellow, department of dermatology, Brigham and Women's Hospital and Harvard Medical School, Boston; Robert S. Kirsner, M.D., Ph.D., professor and vice chairman of dermatology and cutaneous surgery, University of Miami Miller School of Medicine; Oct. 24, 2011, presentation, American Association for Cancer Research, International Conference on Frontiers in Cancer Prevention Research, Boston