Rates of gastrointestinal cancers among people under 50 are increasing across the globe. In the U.S., colorectal cancer is the leading cause of cancer death in men under 50 and second for women behind breast cancer. Each generation born since the 1950s has had higher risk than the one before.
在全球範圍，50歲以下人群的胃腸道癌症發病率正在上升。在美國，結腸直腸癌是造成50歲以下男性因癌症死亡的首要原因，對於女性來說，結腸直腸癌是僅次於乳腺癌的第二大殺手。自20世紀50年代以來出生的每一代人，其患癌風險都高於上一代人。
"Everything you can think of that has been introduced in our society since really the 1960s, the post-World War II era, is a potential culprit," said Dr. Marios Giannakis, a gastrointestinal oncologist at the Dana-Farber Cancer Institute in Boston.
「你能想到的自20世紀60年代以來，也就是二戰後引入我們社會的一切，都是潛在的罪魁禍首，」波士頓丹娜·法伯癌症研究所(Dana-Farber Cancer Institute)的胃腸道腫瘤學家馬裡奧斯·吉安納基斯(Marios Giannakis)博士說。
Robert F. Kennedy Jr., President-elect Donald Trump's pick for Health and Human Services secretary, has pointed to ultra-processed foods and chemicals in medicines and the environment. Cancer doctors share some of his suspicions about diet and exposure to contaminants such as microplastics, shards that make their way from packaging or clothing into our bodies through water and food. They are scrutinizing those and other potential hazards including "forever chemicals" and even light.
美國總統唐納德·特朗普(Donald Trump)的衛生與公眾服務部長人選小羅伯特·肯尼迪(Robert F. Kennedy Jr.)認為，超加工食品以及藥品和環境中的化學物質都與癌症發病率上升有關。腫瘤醫生的看法與他的一些疑慮不謀而合，他們認為，飲食以及接觸微塑膠（這些塑膠碎片通過水和食物，從包裝或衣物中進入我們體內）等污染物導致癌症發病率上升。他們正在仔細考察這些污染物和其他潛在危險物質，包括「永久化學物質」（譯者注：多指全氟和多氟烷基物質，這些物質不易分解，會在環境和人體中積累）乃至光線。
"We're all concerned and want to do something quickly and act quickly, but we want to do so based on sound science," said Dr. Andrew Chan, director of epidemiology at Mass General Cancer Center in Boston.
「我們都對此感到關切，希望儘快做些什麼，儘快採取行動，但我們希望將行動建立在可靠的科學基礎之上，」波士頓馬薩諸塞州綜合癌症中心(Mass General Cancer Center)流行病學主任安德魯·陳(Andrew Chan)博士說。
His team has found connections between early-onset colorectal cancer risk and obesity, consuming a lot of sugar-sweetened beverages and physical inactivity. But those studies don't prove a direct cause.
他的團隊發現，結直腸癌早發風險與肥胖、大量飲用含糖飲料和缺乏運動有關。但這些研究無法證明存在直接的因果關係。
Chan's team is expanding its work to incorporate studies that track more people and analyze blood, tumor and stool samples. They will scour the results for potential carcinogens, then expose mice to them and see if cancers develop.
陳博士的團隊正在擴大工作範圍，納入對更多人進行追蹤以及分析血液、腫瘤和糞便樣本的研究。他們將在研究結果中尋找潛在的致癌物質，然後讓小鼠接觸這些致癌物質，看小鼠是否會罹患癌症。
They plan to first focus on obesity and alcohol, said Yin Cao, a cancer epidemiologist from Washington University School of Medicine in St. Louis, who co-leads the work with Chan.
與陳博士共同牽頭這項研究的圣路易斯華盛頓大學醫學院(Washington University School of Medicine)癌症流行病學家Yin Cao說，他們計劃首先關注肥胖和酒精。
On Friday, the U.S. Surgeon General said alcoholic beverages should carry cancer warnings to increase awareness that the drinks are a leading cause of preventable cancers.
去年12月底，美國衛生局局長(U.S. Surgeon General)表示，含酒精飲料應標註致癌警告，以使人們更好地認識到，這種飲料是造成可預防癌症(preventable cancers)的主要原因。
Excessive alcohol use is linked with risk for early colorectal cancer, studies show, along with diets high in fat and added sugars. One study found people who ate more ultra-processed foods had a greater risk of precursors to colon cancer.
研究表明，過量飲酒以及高脂肪和高添加糖飲食與結直腸癌早發風險有關。一項研究發現，食用較多超加工食品的人發生結腸癌前病變的風險較高。
The group plans to test ways to lower risks, including whether prescribing weight-loss drugs including Ozempic can help prevent colorectal cancer. Another trial will assign some participants a healthier diet and study whether changes in the bacteria and pathogens in the gut, called the microbiome, affect their risk.
該研究小組計劃測試各種降低風險的方法，包括考察使用司美格魯肽(Ozempic)等處方減肥藥是否有助於預防結直腸癌。另一項試驗將為一些參與者安排更健康的飲食，並研究腸道中細菌和病原體（稱為微生物組）的變化是否會影響參與者罹患癌症的風險。
"There's an interplay most likely between the things we eat, the bacteria in the gut, and what those bacteria produce," said Dr. Jordan Kharofa, a gastrointestinal-cancer specialist at the University of Cincinnati Cancer Center, who isn't involved in the study.
「我們吃的東西、腸道中的細菌以及這些細菌產生的物質之間很可能存在相互作用，」辛辛那提大學癌症研究中心(University of Cincinnati Cancer Center)的胃腸道癌症專家喬丹·哈羅法博士(Dr. Jordan Kharofa)說。
Kharofa and other researchers have uncovered links to diets high in sulfur, which results from consuming lots of liquor and processed meat and few fruits and vegetables. Gut bacteria can turn that sulfur into hydrogen sulfide, which could inflame the colon and raise cancer risk.
哈羅法和其他研究人員發現了胃腸道癌症與高硫飲食之間的關聯，造成飲食高硫的原因是攝入大量酒類和加工肉類，而很少吃水果和蔬菜。腸道細菌能夠將硫轉化為硫化氫，這可能使結腸發炎，增加患癌風險。
But some patients don't fit that description at all.
但一些患者的情況完全不符合這種描述。
"They are very, very health conscious, and then they come into your clinic and they're 33 and they've got stage-four colon cancer," said Dr. Marwan Fakih, a gastrointestinal oncologist at City of Hope in Duarte, Calif. "There's no question we're missing something."
「他們非常非常注重健康，結果他們來到你的診所看病，他們才33歲，卻得了第四期結腸癌，」加利福尼亞州杜阿爾特市的醫療機構City of Hope的胃腸道腫瘤學家馬爾萬·法基赫(Marwan Fakih)博士說。
Some researchers are looking at antibiotics, which disrupt the microbiome. One California team analyzed medical records and failed to find a solid link to broad-spectrum antibiotics, but the early results suggest long-term use could increase risk.
一些研究人員將目光投向抗生素，因為抗生素會破壞微生物組。加利福尼亞州的一個研究小組分析了醫療記錄，但未能發現罹患癌症與廣譜抗生素之間的確鑿聯繫，不過，初步結果表明，長期使用抗生素可能會增加患癌風險。
At the University of California, Irvine, cancer biologist Selma Masri has shown in mice that changing the body's internal clock, called the circadian rhythm, changes the diversity and abundance of gut bacteria. Some of the changes were linked to reduced levels of mucus that protects the gut lining from harmful bacteria.
加州大學歐文分校(University of California, Irvine)的癌症生物學家塞爾瑪·馬斯里(Selma Masri)在小鼠身上發現，如果改變人體內部時鐘（稱為晝夜節律），會使腸道細菌的多樣性和丰度發生變化。其中一些變化與保護腸道黏膜免受有害細菌侵襲的黏液水平降低存在關聯。
She also found a link between disrupting the circadian clock and colorectal cancer. Masri and some other scientists think near-constant light from cellphones, laptops and other devices could throw off internal clocks and promote cancer growth by tampering with the immune system, metabolism and the microbiome.
她還發現，擾亂晝夜節律與結直腸癌之間存在聯繫。馬斯里和其他一些科學家認為，來自手機、筆記本電腦和其他設備的幾乎持續不斷的光線可能會擾亂人體內部時鐘，並干擾免疫系統、新陳代謝和微生物組，由此促進癌症的發展。
"The amount of light pollution that's gone up has been staggering," Masri said.
「光污染的加劇令人震驚，」馬斯里說。
Other researchers used drinking water to expose mice to a chemical called PFOS, used to make products resistant to stains and oil and part of the family of "forever chemicals" known as PFAS. They found changes in mice's intestinal tissue that could increase their risk of developing colorectal cancer.
另一些研究人員讓小鼠通過飲用水來接觸一種名為全氟辛烷磺酰基化合物的化學物質，這種物質用於製造耐污耐油產品，屬於被稱為「永久化學物質」的大家族。他們發現，小鼠腸道組織的變化可能會增加它們罹患結直腸癌的風險。
"We don't have all the answers yet," said Jane Figueiredo, a professor of medicine at Cedars-Sinai Medical Center in Los Angeles. "There might not be a magic bullet."
「我們還沒有找到全部答案，」洛杉磯Cedars-Sinai醫學中心醫學教授簡·菲格雷多(Jane Figueiredo)說。「可能並沒有解決問題的靈丹妙藥。」
