什么是结肠和直肠癌？Symptoms, Causes, Diagnosis, Treatment, and Prevention

结肠癌影响大肠的结肠癌是其中之一最常见的癌症in the United States.

Medical experts typically group it with rectal cancer in a category called colorectal cancer.

Colorectal cancer is the fourth most common cancer among men and women in the United States, after lung, breast, andprostate cancer（并排除皮肤癌）。

It is also the second leading cause of cancer death in the United States, behind肺癌。

结肠和直肠是消化系统的一部分。结肠大约五英尺长，大部分大肠道。直肠构成了最终六英寸的大肠，被认为是结肠和肛门之间的通道。

Colorectal cancer occurs when abnormal cells in the colon or rectum grow uncontrollably, crowding out healthy cells.

根据美国癌症协会（ACS）的说法，超过96％的结肠和直肠癌是一种称为腺癌的类型。（1)

Adenocarcinomas are cancers that begin in glandular (secretory) cells, found in tissues that line certain internal organs. Glandular cells produce amucus润滑结肠和直肠。

结肠和直肠癌通常从结肠或直肠的衬里开始以称为结肠直肠息肉的异常生长。

许多有息肉的人都没有继续发展癌症。具有大息肉（大于1厘米）的个体，多种息肉或具有发育不良（异常但尚未癌细胞的息肉）的风险最大。

How Common Is Colon Cancer?

Around 1 in 20 Americans will develop colon cancer or rectal cancer at some point in their lives, according to the most recent data (2013–2015) from the National Cancer Institute (NCI). (2)

This data also suggests that more than 1.3 million people are living with colorectal cancer.

Looking at projections for 2021, the American Cancer Society estimates that close to 105,000 new cases of colon cancer and more than 45,000 new cases of rectal cancer are diagnosed in the United States annually.

Colorectal cancer makes up about 8 percent of all new cancer cases in the country, according to the NCI.

The Importance of Colon Cancer Screenings

Getting regular screening tests is essential for preventing colorectal cancer.

这些测试让医生寻找this cancer in the general population, assessing people who have no symptoms of the disease.

放映可以帮助医生检测和去除癌症之前的结肠直肠息肉。根据ACS，新息肉需要10〜15岁时变成癌症。

检查还可以检测结肠癌和直肠癌cancer early, when these diseases are most treatable.

If colorectal cancer is found at the local stage, before it spreads beyond the colon or rectum, the five-year survival rate is around 90 percent.

Unfortunately, only a little more than one-third of all colon cancers and rectal cancers are found this early, in large part because of inadequate screening.

美国预防性服务工作队（USPSTF），为策略制定bob sports app 和私人保险公司在实惠的护理法案下，用于推荐平均风险的人民的结直肠癌，从50岁开始。

But in May 2018, the American Cancer Society revised its guidelines and shifted their recommendation to 45, and the苏斯普斯特跟着诉讼。（3)

The change was prompted by an analysis of data revealing increasing incidence of colon cancer andrectal cancer among younger Americans。

New research puts at least some of the blame for this problem on rising obesity rates.

A study published in October 2018 in the journalJAMA肿瘤学tracked the health of over 85,000 women for 22 years and found that the higher a woman’sbody mass index (BMI)，她在50岁之前发展结直肠癌的风险越大。（4)

什么导致结肠癌and rectal cancer? Researchers are still trying to answer that question fully. They do know that a small number of people develop colorectal cancer because of rare genetic mutations passed down through their families. Yet for the vast majority of patients, colorectal cancer reflects a complex interplay between genetics and lived experiences.

非常少数结肠直肠癌可能是由父母遗传的突变引起的。获得大多数基因突变，这意味着它们在一个人的生命期间发生。

In some cases a mutation in the APC gene, which normally keeps cell growth in check, may play a part.

医生已经确定了与结肠有关的一些因素cancer riskand rectal cancer risk that increase a person’s odds of developing disease.

Weight, physical activity levels, and diet appear to have a stronger connection to these cancers than they do to any other type of cancer.

可能在一个人的修改范围内的风险因素包括：

• Obesity or excess weight, especially around the midsection
• 身体不活跃的生活方式
• A diet that includes lots of red meat (beef and lamb) and processed meat (certain luncheon meats and hot dogs)
• 抽烟
• Heavy alcohol use

Risk factors that are not under a person’s control include:

• 年龄（尽管个体可以在任何年龄发生结直肠癌，超过50人的风险最高。）
• A personal or family history of colorectal cancer or polyps
• A personal history of inflammatory bowel disease, such as Crohn’s disease or ulcerativecolitis
• 罕见的遗传遗传综合征，如林奇综合征
• African American or Eastern European Jewish heritage
• Type 2 diabetes

Learn More About the Causes of Colon Cancer

预防结直肠癌的最好办法是圣op it before it starts. First off: Don’t smoke. Although people associate cigarettes with lung cancer, they are less aware of its strong connection to colorectal cancer.

避开结肠癌和直肠癌的其他方式包括保持健康的体重，定期锻炼，避免中度至重饮酒，并在健康的饮食后保持红色和加工肉的最低饮食。

Following the recommended schedule for screening tests, such as colonoscopies, can also help doctors find and remove potentially precancerous growths called polyps. Removal of polyps detected through screening is one reason the death rate from colorectal cancer has been dropping over the past few decades.

Learn More About Colon Cancer Prevention

结肠直肠癌可能挑战，因为早期检测，因为它可能不会引起症状，直到它更先进。当症状发生时，它们很容易归咎于其他东西 -hemorrhoids, for instance, or肠易激综合症。

When in doubt, the smart decision is to speak with a doctor as soon as possible.

The most common symptoms include:

• A change in bowel habits, such as diarrhea,constipation, or narrowing of the stool, that lasts for more than a few days
• A feeling of needing to have abowel movementthat is not relieved by having one
• Rectal bleedingwith bright red blood
• Blood in the stool, which can make feces look dark
• Cramping orabdominal pain
• Weakness or fatigue
• 无法解释的减肥

Learn More About Colon Cancer Symptoms

Staging colorectal cancer — describing the extent of the disease — helps doctors make treatment decisions and predict outcomes. For colon cancer and rectal cancer, physicians review imaging scans such as CT (computerized tomography) scans and other tests to see whether the cancer is limited to the inner lining of the colon or rectum; whether it has grown into the colon or rectal wall; has spread to nearby lymph nodes; or has metastasized to further organs or sites in the body. Physicians quantify all this information to determine a stage from 0 to 4. Generally, the lower the stage, the less advanced the disease is, and the better the prognosis.

RELATED:Here’s the Recipe to Keep Colon Cancer at Bay

Learn More About Colon Cancer Stages

If you have colon cancer or rectal cancer, you will likely have surgery, radiation therapy, or chemotherapy — or some combination of these treatments.

手术往往是许多早期结肠癌和大多数直肠癌的首选。A.colonoscopy, for instance, doctors remove diseased tissue using instruments passed through a colonoscope (a long, narrow tube inserted into the body through the anus).

Radiation therapy employs X-rays or other types of radiation to destroy cancer cells.

Chemotherapy utilizes medicines that kill cancer cells and shrink tumors.

What’s more, researchers have been making important advances in the emerging field of targeted therapy — drugs that attack cancer cells with unique genetic or protein targets.

Scientists are also actively investigating immunotherapy, which uses the body’s own immune system to battle cancer.Clinical studies have shown that immunotherapy drugs called checkpoint inhibitors can help a small subset of colorectal cancer patients whose tumors have specific genetic changes.

Learn More About Colon Cancer Treatment

Sometimes an inherited gene mutation leads to an increased risk of colon cancer. When more than one close family member has been affected by colon cancer, a doctor may suggest that family members be tested for Lynch syndrome. A person with Lynch syndrome has up to an 80 percent lifetime risk of colon cancer and up to a 60 percent chance of endometrial cancer. It also increases the risk for gastric cancer,ovarian cancer, small bowel, brain, urinary tract, hepatobiliary tract (liver, bile ducts, andgallbladder), and sebaceous gland tumors.

Learn More About Lynch Syndrome

At some point in the process of — or after — acancer diagnosis, you may find yourself in need of organizations that can step in and provide information, support, and help with unforeseen needs, like financial aid and words of wisdom from people who have been there. We’ve collected some of the most helpful resources for you, for when you need them most.

RELATED:Everything You Need to Know About the Ulcerative Colitis–Colon Cancer Connection

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