阑尾癌

概述

Appendix cancer is a rare type of cancer that begins when cells in the appendix grow out of control. The appendix is a small pouch attached to the first part of the large intestine. Because appendix cancer is so uncommon, many people only find out they have it after having surgery to remove the appendix to treat appendicitis. But they find out that what their healthcare professionals thought was appendicitis was really appendix cancer. Appendix cancer is sometimes called appendiceal carcinoma or appendiceal cancer.

There are several types of appendix cancer, and each one behaves differently. Some types grow very slowly and may stay in the appendix for years. Others can spread more quickly to the lining of the abdomen or to other organs. How serious it is depends on the cancer type, how far it has spread, and how the cells look under a microscope.

Slow-growing, low-grade appendix cancers can often be cured with surgery. But more-aggressive ones may need additional treatment, such as traditional chemotherapy or a specialized procedure called hyperthermic intraperitoneal chemotherapy (HIPEC).

Even though appendix cancer is still very rare — affecting only about 1 to 2 people per 100,000 each year — it has been diagnosed more often in recent years, including in younger adults. Many people live for years after diagnosis, especially when the cancer is found early or can be completely removed with surgery.

Types

Appendix cancer can begin in different kinds of cells inside the appendix. These cancers are broadly grouped into two main types: epithelial appendix cancers and neuroendocrine appendix cancers. Each behaves differently and may require different treatments.

Epithelial appendix cancers

Epithelial cancers start in the cells that line the inside of the appendix. These cells typically help make a jellylike fluid, called mucus, that protects the lining of the digestive tract. When these tumors grow, many produce large amounts of mucus. If the appendix ruptures or leaks, this mucus can spread through the abdomen and cause a condition called pseudomyxoma peritonei (PMP).

Epithelial appendix cancers include a few subtypes:

• Adenocarcinomas. These cancers start from the gland cells that line the appendix. There are two main types: mucinous and nonmucinous. Nonmucinous type also is called colonic type. Adenocarcinomas are often treated with a more extensive surgery, such as removing part of the colon.
• Appendiceal mucinous neoplasms (AMNs). These tumors make a jellylike fluid called mucus. AMNs can be low-grade (LAMN) or high-grade (HAMN). LAMN tumors grow slowly, while HAMN tumors are more likely to spread.
• Goblet cell adenocarcinomas. These rare tumors have features of both gland-forming and hormone-producing cells. They tend to grow faster than neuroendocrine tumors and often need more-extensive surgery and sometimes chemotherapy.
• Signet ring cell carcinomas. This is a rare and aggressive type of adenocarcinoma. The cancer cells look like rings under a microscope and tend to spread early. These usually require intensive treatment.

Neuroendocrine appendix cancers

Neuroendocrine tumors (NETs), sometimes called carcinoid tumors, start in hormone-producing cells. These cells help regulate digestion. NETs are the most common type of appendix tumor and are often found unexpectedly after surgery for suspected appendicitis. Many NETs grow slowly and can be treated successfully by removing the appendix. Larger tumors or those that involve lymph nodes may require additional treatment and follow-up.

症状

Appendix cancer can be hard to detect because many people don't have symptoms at first. In fact, it's often found by accident during surgery for appendicitis or another abdominal problem. When symptoms do appear, they can be mild and easy to mistake for other conditions.

If the cancer grows larger, symptoms may include:

• Pain in the lower right side of the belly. This is the same area where appendicitis pain usually happens.
• A growing belly size caused by mucus or fluid buildup inside the abdomen, which may happen with mucinous tumors or a condition called pseudomyxoma peritonei.
• Nausea or vomiting.
• Feeling full soon after you eat.

When to see a doctor

Because these symptoms can be caused by many other health problems, it's important to talk with a healthcare professional if symptoms last more than a few days or seem unusual for you. Early evaluation and imaging can help find the cause and, if needed, guide treatment.

病因

Medical experts don't yet know the exact cause of appendix cancer. It happens when healthy cells in the appendix begin to change and grow in ways they shouldn't. Over time, these cells can form a tumor.

Researchers believe these changes may begin in the DNA inside cells, but the reason this happens is still not clear. Unlike some cancers, appendix cancer has no known lifestyle or environmental cause.

In most people, appendix cancer seems to occur by chance. It's important to remember that nothing you did or didn't do caused it. Scientists continue to study why certain appendix cells become cancerous and how to detect these changes early.

风险因素

Although the cause of appendix cancer isn't known in most cases, research shows some associations with older age and inherited genetic variations. These factors do not guarantee that someone will develop appendix cancer. They merely highlight areas where risk might be slightly higher. Because this cancer is so rare and understudied, definitive risk factor profiles are not yet established.

并发症

Appendix cancer can lead to problems in the belly and other parts of the body, especially if it spreads or causes a buildup of mucus or fluid. Some possible complications include:

• Pseudomyxoma peritonei (PMP). Some appendix tumors make a jellylike mucus that can leak into the abdomen. This mucus can fill the belly and put pressure on the organs, leading to bloating, discomfort or trouble eating.
• Spread of cancer, called metastasis. If the cancer moves to other areas — such as the lining of the abdomen, ovaries or liver — it can cause new symptoms such as swelling, weight loss or fatigue.

These complications can typically be treated or managed. Regular follow-up and imaging help healthcare professionals find and address problems early.