Updated August 23rd, 2023

Medical Mystery: Why Are So Many More Young People Getting Appendix Cancer?

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Appendix Cancer Is On The Rise

Cancer researchers are unsure what’s leading to the explosive growth in appendix cancer cases over the past 20 years.
Although the disease is often discovered in middle-aged people, appendix cancer can affect all ages, and findings from a 2020 study revealed that the number of people having of malignant appendiceal tumors increased by 232% in the U.S. between 2000 to 2016, ONC Live reported this year.
Andreana N. Holowatyj, PhD, MSCI, an assistant professor of medicine and cancer biology at Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center (VICC), told ONCLive that appendix cancer has been found to be affecting more younger adults.
Holowaty is in charge of the National Cancer Institute Appendiceal Cancer Consortium (APPECC) study, which is exploring why appendiceal cancer cases are rapidly rising and clarifying risk factors of appendix cancer.

The appendix cancer rate has been on the rise over the past 20 years and cancer researchers are unsure as to what’s causing the explosive growth in cases.

Appendiceal cancer, also known as cancer of the appendix continues to be extremely rare and is commonly seen in people between the ages of 50 and 55 years old, however, more younger people are being diagnosed with the disease.

Cases of appendix cancer is is thought to affect approximately 1 or 2 people per 1 million every year, according to the National Cancer Institute, but a 2020 study revealed a sharp increase in the number of people having of malignant appendiceal tumors.

Researchers with the study, published in JAMA Oncology, found that between 2000 and 2016, the number of malignant appendiceal cancer diagnoses increased by 232% in the U.S. and 292% in Canada, with more incidences of early onset appendiceal cancer.

“The increase was noted for malignant adenocarcinomas and neuroendocrine appendiceal tumors in both countries. The increase occurred across all age groups, sexes, and stages of disease,” the study, titled “Continued increasing incidence of malignant appendiceal tumors in Canada and the United States,” stated in its results.

“The highest rate of increase was noted for appendiceal neuroendocrine malignant tumors diagnosed among the youngest age groups. The rate of appendectomies was stable in the recent time periods, resulting in a decreasing rate of appendectomies per malignant appendiceal tumor diagnosis.”

The investigators ultimately concluded that although the incidence of malignant appendiceal tumors are on the rise, it is “not likely due to the increasing diagnosis of asymptomatic tumors at the time of appendectomies.”

Andreana N. Holowatyj, PhD, MSCI, an assistant professor of medicine and cancer biology at Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center (VICC) who led the 2020 study’s research team, told ONCLive in a recent interview that appendix cancer has been found to be affecting more younger adults.

Holowaty is in charge of the National Cancer Institute Appendiceal Cancer Consortium (APPECC) study, which is exploring why appendiceal cancer cases are rapidly rising and clarifying risk factors of appendix cancer.

Holowatyj said, “My team conducted a few studies, particularly one that wanted to look at the burden of appendix cancers in young adults.

“And what we strikingly found there was that, in contrast to the fact that about 1 in every 5 colorectal cancer patients is diagnosed before the age of 50, we found that 1 in every 3 [30.8%] appendix cancer patients are diagnosed before age 50.4.

“Noting this really disproportionate burden in younger patients really spurred a lot of the subsequent work that my lab has done and continues to do.”

She also pointed out that the disease is more prevalent in patients of color, adding, “Appendix cancer, much like many other cancers, has a lot of different characteristics on a cellular level, or what the cells look like under the microscope.”

“So, there’s a lot of pathological differences that lead to different histologies. Again, with the rarity of this malignancy, it’s really hard to study. Specifically, what is the genetic predisposition in this one group of patients with, let’s say, appendiceal adenocarcinoma versus goblet cell carcinoma?

“That’s the trajectory we’re hoping to move forward in with our clinical study that’s now open at Vanderbilt and across the country, for patients with appendix cancer, but it’s too soon to say.”

Holowatyj, along with her colleagues, also shared data they found on the “prevalence and spectrum of inherited cancer susceptibility gene sequence variations in patients with appendiceal cancer and the utility of germline genetic testing for this population.”

They discovered that about 1 in 10 patients, out of 131 appendiceal cancer patients, had an inherited gene sequence variation which was linked with cancer susceptibility.

“That study really is the tip of an iceberg, and potentially quite a big iceberg, in that it’s spurred us opening a clinical study both at Vanderbilt and nationwide called the Genetics of Appendix Cancer study or GAP [NCT05734430], where any individual diagnosed with appendix cancer in the United States is eligible to participate and will help us learn more about this genetic predisposition and these genetic factors overall,” Holowatyj added.

Understanding Appendix Cancer

The Appendix Cancer Pseudomyxoma Peritonei Research Foundation states that patients diagnosed with appendix cancer have reported experiencing symptoms including:

Appendicitis
Increased abdominal girth
Bloating
Pain/discomfort in the abdominal region can be a dull ache or sharp pains similar to appendicitis
Hernia symptoms often initially diagnosed as a hernia, especially in men
In women, symptoms of an ovarian cyst or tumor often initially misdiagnosed as ovarian cancer
Ascites (fluid) buildup in the abdominal cavity

Types of Appendix Cancer

There are various types of appendix cancer, which include:

Low grade mucinous neoplasms of the appendix (formerly known as mucinous cystadenomas), which is a borderline or low-grade malignant tumor.
Adenocarcinomas are cancerous tumors created by gland-forming cells that line the inside of the appendix. They may spread to other parts of the body, other organs in the abdomen or to the local lymph nodes.
Signet-ring cell adenocarcinomas (so called because of the physical appearance of the cells under the microscope) are a subset of adenocarcinomas of the appendix. Signet ring cell cancers are generally considered more aggressive than other adenocarcinomas because they are faster growing, more likely to spread to local lymph nodes and harder to completely remove at the time of surgery.
Adenocarcinoid cancers (also known as Goblet Cell Carcinoids or Goblet Cell Adenocarcinoma) are a hybrid tumor of both adenocarcinoma and a neuroendocrine (or carcinoid cancer). The expected behavior of adenocarcinoid tumors tends to follow that of the adenocarcinoma portion of the tumor.
Neuroendocrine (Carcinoid) tumors arise from a subset of cells lining the appendix known as neuroendocrine cells. They are generally considered to be slow growing and have a very different behavior than adenocarcinomas of the appendix.

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Advancements In Appendix Cancer

According to The University of Texas MD Anderson Cancer Center, a top ranked cancer center in the U.S. which often sees patients with this rare type of cancer, treatment options for appendix cancer vary depending on the type of tumor, where it is in the appendix, whether it has spread, and overall health status.

“Surgery is the main treatment for appendix cancer. The type of surgery depends on the type of appendix cancer,” the center explains. “If appendix cancer has spread within the abdomen, the most effective approach usually involves cytoreductive (tumor debulking) surgery to remove the tumor and mucin in the abdomen. Parts of the intestine, gallbladder, ovaries, uterus and lining of the abdominal cavity may be removed.”

During the tumor debulking surgery, hyperthermic intraperitoneal chemotherapy (HIPEC), a heated chemotherapy, is performed. Chemotherapy is used for patients with this disease, either with a single drug or a combination of two or more drugs, if needed.

Over the past few decades, there have been some major advancements in the fight against appendix cancer.

Back in 2004, a woman named Pam Philips went to see surgical oncologist Dr. Armando Sardi at Mercy Medical Center in Maryland after she was misdiagnosed for years while enduring abdominal pain and discomfort, only to be told by Sardi that her body was battling a type of appendiceal cancer, according to WBAL-TV.

Speaking to the news outlet about her case, Philips said, “We need to get the word out to primary doctors so they can diagnose early, so you won’t go years with this growing in your abdomen.” But in 2015, a surgery with a high success rate become available for patients battling the disease.

Dr. Sardi said the cancer is very curable these days with the help of hyperthermic intraperitoneal chemotherapy (HIPEC) surgery, something which kills cancer cells in the abdomen and reduces recurrence chances.

He explained, “The treatment is called HIPEC. Really what it consists of is going in and removing all the tumor first. That’s the most important thing to do. It takes between 8 and 12 hours. Then you give 90 minutes of heated chemotherapy.”

WATCH: What Is Hyperthermic Intraperitoneal Chemotherapy

Hyperthermic intraperitoneal chemotherapy (HIPEC) is a surgery in which a patient’s abdominal cavity is filled with chemotherapy drugs that have been carefully heated to a temperature slightly higher than the body’s average temperature.

While the drug is injected into the cavity, the patient is placed in a special cooling blanket to ensure the body does not overheat.

This is also accomplished with some manual work from the surgeon and others in the room, who will rock the patient back and forth for hours to ensure the drug reaches every part of the cavity.

If this is done correctly, the drug can kill the cancer cells that remain after surgery, therefore reducing any chance of recurrence.

There are several reasons why individuals prefer HIPEC treatments, such as:

single treatment during a single visit
decreased risk of toxic effects because the drug is confined to the abdomen
surgeon can administer a more intense dose of chemotherapy

This procedure works best in individuals with soft tissue sarcomas, appendix cancer, desmoplastic small round cell tumors (DSRCT), and other cancers in the abdominal cavity.

How to Find Help After a Rare Cancer Diagnosis

Tens of thousands of people are diagnosed with rare types of cancer every year. And people facing an uncommon diagnosis may find it difficult to find someone who specializes in their illness. Here’s what our SurvivorNet experts say about ways that patients can find helpful resources and get the help they need.

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