专家视点—公众对癌症风险的误解

作者Betsy Bates Freed 博士是加州圣巴巴拉市临床心理学医生和医学新闻记者。

如果想知道人类如何判断风险，不妨去买彩票或者玩玩老虎机。我们往往并不清楚自己由此成为百万富翁的几率，而我们对风险的误解通常也并不限于金钱方面。

有研究证实，人们对皮肤癌、食物中毒、心血管疾病、驾车发送短信导致的事故以及无烟烟草的风险认知极不准确。我们甚至非常热衷地认为，虽然公众的体型正在“横向发展”，但我们的腰臀比却恰到好处。

在美国临床肿瘤学会(ASCO)年会上报告的两项研究结果强调了对癌症风险的错误认知情况，颇值得关注。

Katherine Lang及其弗吉尼亚州立联邦大学和约翰霍普金斯大学的同事报告，年轻成年女性对其乳腺癌和结肠癌终生风险存在极大误解。研究者对入组癌症风险沟通研究的369例女性进行问卷分析后发现，基于家族史和其他因素，一生中可能患乳腺癌的受访者比例为11%，但她们估计的比例却高出1倍以上，达24%。对于结肠癌风险，虽然错误认知比例略低但趋势相似。虽然实际上仅有3%的受访者(平均年龄33岁)面临结肠癌终生风险，但自认为将会罹患结肠癌的受访者比例高达19%。

另一项来自爱尔兰的研究显示，在参与在线调查的525例受访者中，81%担心癌症风险。然而，普通人群有可能被确诊为癌症的比例无疑远远低于该数据。在这项由爱尔兰考克大学的Lisa Burns领导完成的调查中，1/3的受访者不知道肥胖是一种风险因素，但同样比例的人认为穿戴紧身胸罩有风险，近半数的人认为撞击胸部可增加乳腺癌发病率，认为压力和手机增加癌症风险的受访者比例分别为85%和86%。在女性受访者 (占受访者的82%)中，87%认为遗传因素“在很大程度上”增加癌症风险。受访者对广为宣传的吸烟增加癌症风险的认知水平较高(99%)。此外，受访者认为加工肉类(86%)、转基因食品(81%)、食品辐射(77%)、清洁剂(73%)、气雾剂(71%)以及奶酪(29%)可诱发癌症。36%的受访者拥有大学文凭。

在降低癌症风险因素的认知方面，最被认可的是有机食品(61%)，其次为排毒饮食(35%)和运气(12%)。作者认为，虽然许多普通人群意识到吸烟和不佳饮食等典型癌症风险因素，但大多数人高估了遗传因素、环境和压力的作用，并对年龄、肥胖和阳光的作用认识不足。

对于致力于预防癌症的人而言，最令人沮丧的研究结果是：1/5的受访者认为终生癌症风险是不可改变的。

爱思唯尔  版权所有

BY BETSY BATES FREED, PSY.D.
Elsevier Global Medical News

If you want to understand how well human beings perceive risk, just stand in line at the gas station when lottery tickets are all the rage, or spend an hour or two loitering at the quarter slots in Las Vegas.

We humans aren’t very swift at calculating the odds of becoming multimillionaires in either setting, and our all-too-human misperception of risk doesn’t stop at our pocketbooks.

Studies document wildly inaccurate perceptions of risks of skin cancer, food poisoning, cardiovascular disease, accidents caused by texting while driving, and smokeless tobacco. We even believe, quite avidly, that while the American public is getting a tad pudgy, our own hip-to-waist ratios are doing just fine.

Two studies presented in poster form at ASCO’s annual meeting in Chicago highlight some pretty eyebrow-raising misperceptions of risk when it comes to cancer.

Such as – the fact that young adult women profoundly misperceive their lifetime risks of breast and colon cancer, as reported by Katherine Lang and her associates at Virginia Commonweath University in Richmond and Johns Hopkins University in Baltimore.

Ms. Lang and her team analyzed responses from 369 women recruited for a study of cancer risk communication and found that 11% would likely be diagnosed with breast cancer in their lives, based on their family history and other factors. More than twice that percentage, 24%, estimated that they would get breast cancer.

The same trend, with slightly lower levels of misperception, held for colon cancer. While 3% of the group – average age, 33years – faced a real lifetime risk of colon cancer, 19% were convinced they would get the disease.

A second study, this one from Ireland, found that 81% of 525 participants in an online survey were concerned about their cancer risk, while, of course, a far lower percentage would be diagnosed with the disease in the general population.

One in three had no clue that obesity might be a risk factor, but the same percentage believed that wearing a tight bra was a risk. Almost half believed that a blow to the breast could up one’s chance of being diagnosed with breast cancer.

Stress was believed to increase cancer risk by 85% of those queried, and cell phones by 86%. Genetics was deemed by 87% of this largely female (82%) cohort to “strongly” increase risk.

The group, surveyed by a team led by nutritional science student Lisa Burns at University College Cork (Ireland), got the well-publicized message that smoking increases cancer risk (99%). In addition, processed meat (86%), genetically modified foods (81%), food irradiation (77%), cleaning agents (73%), aerosol use (71%), and cheese (29%) were considered cancer promoters by the respondents, 36% of whom held college degrees.

What lowers cancer risk?

The winners in that category were organic food (61%), followed by detox diets (35%), and luck (12%).

The authors concluded that while many members of the general public have an awareness of classic risk factors for cancer such as smoking and a poor diet, “most overestimate risk attributable to genetics, environment, and stress, and underestimate age, obesity, and sunlight.”

Most depressing of all to those who would place their bets on cancer prevention messages, “One in 5 believes lifetime risk cancer is non-modifiable,” the group concluded.

Dr. Freed is a clinical psychologist in Santa Barbara, California, and a medical journalist.