什么是筛查？
筛查是在人们出现症状之前检查癌症。这种方法可以在早期发现癌症。当异常病变组织或癌症可以早期发现时，治疗可能会更容易。当症状出现时，癌细胞也许已经开始扩散。
科学家正在试图更好地了解哪些人易患某些类型的癌症。他们也研究我们的行为和所处的环境，观察这些因素是否会诱发癌症。这些信息可以帮助医生为癌症筛查的适宜人群、筛查方法以及筛查频率提供建议。
切记，医生如果建议您进行筛查，并不一定认为您已经患有癌症。尚未出现癌症症状时，才会进行癌症筛查。
如果筛查结果异常，需要进行更多检查以确认是否罹患癌症。这些检查称为诊断性检查。
What is screening?
Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.
It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms.
If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.
胃癌的一般信息
胃癌是一种在胃内膜上形成恶性（癌）细胞的疾病。
胃呈J形，位于上腹部。胃属于消化系统的一部分，该系统负责处理摄入的营养物（维生素、矿物质、碳水化合物、脂肪和水），并帮助将废物排出体外。食物经食管这一中空的肌性管道从咽移动至胃。经部分消化的食物离开胃后进入小肠，随后进入大肠。
食管和胃是上消化道（消化）系统的一部分。
胃壁由三层组织构成，即黏膜层（内层）、肌层（中层）和浆膜层（外层）。胃癌始于黏膜层沿壁细胞，随着不断生长扩散到外层。
参考下列PDQ总结，获取更多关于胃癌的信息：
胃癌在美国并不常见。
相比亚洲、欧洲、中美洲和南美洲一些地区，胃癌在美国比较少见。胃癌是上述地区的主要死亡原因之一。
1930年以来，美国胃癌新发病例大幅下降。下降原因并不明确，但可能与食物储藏条件的改善和饮食变化相关，例如盐摄入量的减少。
高龄和一些慢性病增加胃癌的患病风险。
任何增加患病机会的原因称为危险因素。具有某种危险因素并不意味着会发生癌症；而不具有某种危险因素也不意味着不会得癌。如果您认为自己可能有罹患胃癌的风险，请与你的医生谈谈。胃癌的危险因素包括以下几个方面：
来自胃癌高发国家的人群患胃癌的风险增加。
General Information About Stomach (Gastric) Cancer
Stomach cancer is a disease in which malignant (cancer) cells form in the lining of the stomach.
The stomach is a J-shaped organ in the upper abdomen. It is part of the digestive system, which processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in foods that are eaten and helps pass waste material out of the body. Food moves from the throat to the stomach through a hollow, muscular tube called the esophagus. After leaving the stomach, partly-digested food passes into the small intestine and then into the large intestine.
The esophagus and stomach are part of the upper gastrointestinal (digestive) system.
The wall of the stomach is made up of 3 layers of tissue: the mucosal (innermost) layer, the muscularis (middle) layer, and the serosal (outermost) layer. Stomach cancer begins in the cells lining the mucosal layer and spreads through the outer layers as it grows.
See the following PDQ summaries for more information about stomach cancer:
Stomach cancer is not common in the United States.
Stomach cancer is less common in the United States than in many parts of Asia, Europe, and Central and South America. Stomach cancer is a major cause of death in these parts of the world.
In the United States, the number of new cases of stomach cancer has greatly decreased since 1930. The reasons for this are not clear, but may have to do with better food storage and changes in the diet, such as lower salt intake.
Older age and certain chronic conditions increase the risk of stomach cancer.
Anything that increases the chance of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk for stomach cancer. Risk factors for stomach cancer include the following:
The risk of stomach cancer is increased in people who come from countries where stomach cancer is common.
胃癌筛查
这些检测方法用于在一个人没有症状时筛查不同类型的癌症。
科学家们对筛查方法进行研究，以找到危害最小和获益最大的方法。癌症筛查试验还旨在表明早期发现（在出现症状之前发现癌症）是否有助于延长一个人的寿命或降低一个人死于癌症的几率。对于某些类型的癌症，如果能在早期发现并给予治疗，康复的机会会更高。
胃癌尚无标准或常规的筛查方法。
研究已关注几种筛查方法，旨在早期发现胃癌。这些筛查方法包括如下几种：
服用钡餐以检测胃癌。患者吞服钡液，钡液流经食管并进入胃。使用X光检查异常区域。
上消化道内镜检查。一根细而发光的管子插入口腔，寻找食管、胃部和小肠起始段的异常区域。
研究表明，利用这些方法对胃癌进行大规模筛查并不会降低胃癌的死亡风险。
还需更多研究来明确筛查美国的胃癌高危人群是否值得。科学家认为，存在某些危险因素的人群可能会受益于胃癌筛查。这些人群包括：
胃癌的筛查方法正在临床试验中进行研究。
有关NCI支持的临床试验的信息可在NCI的临床试验搜索网页上找到。其他组织支持的临床试验可在ClinicalTrials.gov网站上找到。
Stomach (Gastric) Cancer Screening
Tests are used to screen for different types of cancer when a person does not have symptoms.
Scientists study screening tests to find those with the fewest harms and most benefits. Cancer screening trials also are meant to show whether early detection (finding cancer before it causes symptoms) helps a person live longer or decreases a person's chance of dying from the disease. For some types of cancer, the chance of recovery is better if the disease is found and treated at an early stage.
There is no standard or routine screening test for stomach cancer.
Several types of screening tests have been studied to find stomach cancer at an early stage. These screening tests include the following:
Barium swallow for stomach cancer. The patient swallows barium liquid and it flows through the esophagus and into the stomach. X-rays are taken to look for abnormal areas.
Upper endoscopy. A thin, lighted tube is inserted through the mouth to look for abnormal areas in the esophagus, stomach, and first part of the small intestine.
Studies showed that screening a large number of people for stomach cancer using these tests did not decrease the risk of dying from stomach cancer.
More studies are needed to find out if it would be worthwhile to screen people in the United States who do have a high risk for stomach cancer. Scientists believe that people with certain risk factors may benefit from stomach cancer screening. These include:
Screening tests for stomach cancer are being studied in clinical trials.
Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.
胃癌筛查的风险
筛查存在风险。
决定是否进行筛查可能是困难的。并非所有筛查都会有所帮助，并且大多数存在风险。进行任何筛查之前，您可以与医生讨论相关事宜。了解筛查的风险以及是否已被证明可降低胃癌的死亡风险是非常重要的。
胃癌筛查的风险包括以下几个方面：
发现胃癌可能并不会改善健康状况或帮助延长您的寿命。
如果您已患晚期胃癌，筛查可能并不会改善您的健康状况或帮助延长您的寿命。
一些癌症永远不会产生症状或危及生命，但如果通过筛查发现，便会加以治疗。而相比于不治疗，对这些癌症进行治疗是否有助于延长寿命，还是会引起严重的副作用，目前并不知晓。
假阴性结果可能会出现。
即使存在胃癌，筛查结果也可能显示正常。人们收到假阴性检查结果（虽已患癌，筛查却显示未患癌）会导致即便已有症状，也可能延迟就医。
假阳性结果可能会出现。
即使未患胃癌，筛查结果可能显示异常。假阳性结果（虽未患癌，筛查却显示患癌）会导致焦虑，并且通常伴随更多也有风险的检查和治疗。
筛查本身也会引起副作用。
上消化道内镜检查可能会引起以下罕见而严重的副作用：
Risks of Stomach (Gastric) Cancer Screening
Screening tests have risks.
Decisions about screening tests can be difficult. Not all screening tests are helpful and most have risks. Before having any screening test, you may want to discuss the test with your doctor. It is important to know the risks of the test and whether it has been proven to reduce the risk of dying from cancer.
The risks of stomach cancer screening include the following:
Finding stomach cancer may not improve health or help you live longer.
Screening may not improve your health or help you live longer if you have advanced stomach cancer.
Some cancers never cause symptoms or become life-threatening, but if found by a screening test, the cancer may be treated. It is not known if treatment of these cancers would help you live longer than if no treatment were given, and treatments for cancer may have serious side effects.
False-negative test results can occur.
Screening test results may appear to be normal even though stomach cancer is present. A person who receives a false-negative result (one that shows there is no cancer when there really is) may delay seeking medical care even if there are symptoms.
False-positive test results can occur.
Screening test results may appear to be abnormal even though no cancer is present. A false-positive test result (one that shows there is cancer when there really isn't) can cause anxiety and is usually followed by more tests and procedures which also have risks.
Side effects may be caused by the screening test itself.
Upper endoscopy may cause the following rare, but serious, side effects:
About This PDQ Summary
About PDQ
Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.
PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.
Purpose of This Summary
This PDQ cancer information summary has current information about stomach (gastric) cancer screening. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
Reviewers and Updates
Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.
The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Screening and Prevention Editorial Board.
Clinical Trial Information
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).
Permission to Use This Summary
PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”
The best way to cite this PDQ summary is:
PDQ® Screening and Prevention Editorial Board. PDQ Stomach (Gastric) Cancer Screening. Bethesda, MD: National Cancer Institute. Updated
Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 3,000 scientific images.
Disclaimer
The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on Cancer.gov on the Managing Cancer Care page.
Contact Us
More information about contacting us or receiving help with the Cancer.gov website can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the website’s E-mail Us.
About This PDQ Summary
About PDQ
Physician Data Query (PDQ) is the National Cancer Institute's (NCI's) comprehensive cancer information database. The PDQ database contains summaries of the latest published information on cancer prevention, detection, genetics, treatment, supportive care, and complementary and alternative medicine. Most summaries come in two versions. The health professional versions have detailed information written in technical language. The patient versions are written in easy-to-understand, nontechnical language. Both versions have cancer information that is accurate and up to date and most versions are also available in Spanish.
PDQ is a service of the NCI. The NCI is part of the National Institutes of Health (NIH). NIH is the federal government’s center of biomedical research. The PDQ summaries are based on an independent review of the medical literature. They are not policy statements of the NCI or the NIH.
Purpose of This Summary
This PDQ cancer information summary has current information about stomach (gastric) cancer screening. It is meant to inform and help patients, families, and caregivers. It does not give formal guidelines or recommendations for making decisions about health care.
Reviewers and Updates
Editorial Boards write the PDQ cancer information summaries and keep them up to date. These Boards are made up of experts in cancer treatment and other specialties related to cancer. The summaries are reviewed regularly and changes are made when there is new information. The date on each summary ("Updated") is the date of the most recent change.
The information in this patient summary was taken from the health professional version, which is reviewed regularly and updated as needed, by the PDQ Screening and Prevention Editorial Board.
Clinical Trial Information
A clinical trial is a study to answer a scientific question, such as whether one treatment is better than another. Trials are based on past studies and what has been learned in the laboratory. Each trial answers certain scientific questions in order to find new and better ways to help cancer patients. During treatment clinical trials, information is collected about the effects of a new treatment and how well it works. If a clinical trial shows that a new treatment is better than one currently being used, the new treatment may become "standard." Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Clinical trials can be found online at NCI's website. For more information, call the Cancer Information Service (CIS), NCI's contact center, at 1-800-4-CANCER (1-800-422-6237).
Permission to Use This Summary
PDQ is a registered trademark. The content of PDQ documents can be used freely as text. It cannot be identified as an NCI PDQ cancer information summary unless the whole summary is shown and it is updated regularly. However, a user would be allowed to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks in the following way: [include excerpt from the summary].”
The best way to cite this PDQ summary is:
PDQ® Screening and Prevention Editorial Board. PDQ Stomach (Gastric) Cancer Screening. Bethesda, MD: National Cancer Institute. Updated
Images in this summary are used with permission of the author(s), artist, and/or publisher for use in the PDQ summaries only. If you want to use an image from a PDQ summary and you are not using the whole summary, you must get permission from the owner. It cannot be given by the National Cancer Institute. Information about using the images in this summary, along with many other images related to cancer can be found in Visuals Online. Visuals Online is a collection of more than 3,000 scientific images.
Disclaimer
The information in these summaries should not be used to make decisions about insurance reimbursement. More information on insurance coverage is available on Cancer.gov on the Managing Cancer Care page.
Contact Us
More information about contacting us or receiving help with the Cancer.gov website can be found on our Contact Us for Help page. Questions can also be submitted to Cancer.gov through the website’s E-mail Us.