Appendix Cancer Awareness Month 2026: The Rare Cancer That Can Mimic Appendicitis

Appendix cancer is a rare condition that many people hear about only when it affects them or someone close to them. Unlike some cancers that have well-known warning signs or routine screening tests, appendix cancer often comes as an unexpected diagnosis. In many cases, it is found after a person seeks care for symptoms that look like appendicitis, such as sudden pain in the lower right side of the abdomen, bloating, swelling, or ongoing abdominal discomfort.

This is what makes awareness so important. During Appendix Cancer Awareness Month 2026, the focus is not only on understanding this rare cancer, but also on recognising why timely evaluation, proper diagnosis, and specialist-guided care matter. While most abdominal pain is not cancer, symptoms that are severe, persistent, unusual, or recurrent should not be ignored.

In this blog, we’ll explain what appendix cancer is, why it can be difficult to detect early, how it may mimic appendicitis, and when it is important to seek medical advice.

What is Appendix Cancer Awareness Month?

Appendix Cancer Awareness Month is observed every August to raise awareness about appendix cancer and pseudomyxoma peritonei, also called PMP. It is represented by the amber ribbon and supported by the Appendix Cancer Pseudomyxoma Peritonei Research Foundation, or ACPMP.

The purpose of this month is simple: to help more people understand a rare cancer that is often found late or unexpectedly. Many people have never heard of appendix cancer until they or someone close to them receives the diagnosis. Awareness can help patients, families, and even healthcare providers recognise why unusual abdominal symptoms, suspected appendicitis, or an unexpected pathology report may need further specialist evaluation.

Each August, ACPMP also runs awareness activities such as the Light Up Amber initiative, where landmarks, buildings, and communities are encouraged to be illuminated in amber in support of people affected by appendix cancer and PMP.

The month also highlights the need for more research. Because appendix cancer is rare, better awareness, education, and research are all important to improve diagnosis, treatment, and long-term care for patients.

What is Appendix Cancer?

Appendix cancer is a rare cancer that starts in the appendix, a small pouch attached to the large intestine in the lower right side of the abdomen. Because the appendix is small and hidden inside the abdomen, cancer in this area may not cause clear symptoms in the early stages.

In many people, appendix cancer is found unexpectedly. It may be discovered during surgery for suspected appendicitis, on an imaging scan, or while doctors are checking symptoms such as abdominal pain, bloating, swelling, or a lump in the abdomen.

Appendix cancer is not the same as colon cancer, even though the appendix is connected to the large intestine. Some appendix cancers behave differently and may spread in different ways, especially within the abdominal cavity.

Not all appendix cancers are alike. The type of tumour, how far it has spread, and whether it has affected nearby tissues or the lining of the abdomen help doctors decide the best treatment plan. This is why proper diagnosis, staging, and review by an experienced cancer team are important.

Types of Appendix Cancer

Appendix cancer is not one single disease. There are different types, and each type can behave differently. Some grow slowly, while others can spread more quickly. Knowing the exact type helps doctors decide the right treatment plan. The types include:

• Low-grade appendiceal mucinous neoplasm (LAMN): This is a slow-growing tumour that produces a mucus-like substance called mucin. If it is removed before it bursts or spreads, the outlook is usually good. However, if it ruptures, mucin-producing cells can spread inside the abdomen and may lead to pseudomyxoma peritonei, or PMP.
• Mucinous adenocarcinoma: This type also produces mucin, but it is more aggressive than LAMN. It can spread inside the abdominal cavity. In some patients, treatment may include surgery to remove visible disease, along with HIPEC, a heated chemotherapy treatment given inside the abdomen.
• Non-mucinous adenocarcinoma, also called colonic-type adenocarcinoma: This type behaves more like colon cancer. It may spread through nearby lymph nodes or to other parts of the body. Treatment may include surgery and chemotherapy, depending on the stage.
• Signet ring cell carcinoma: This is a rare and aggressive type of appendix cancer. It can spread early and usually needs specialist cancer care.
• Goblet cell carcinoma: This type has features of both gland-forming cancer cells and neuroendocrine cells. It can behave more aggressively than some other appendix tumours, so treatment depends on how far it has spread.
• Neuroendocrine tumour of the appendix, sometimes called a carcinoid tumour: This type is often found by chance after appendix surgery. Many small tumours are treated successfully with appendix removal alone, but larger tumours may need more detailed evaluation and additional surgery.

What is Pseudomyxoma Peritonei (PMP)?

Pseudomyxoma peritonei, or PMP, is a rare condition that can happen in some types of appendix cancer, especially mucin-producing tumours.

To understand PMP, it helps to first understand the abdomen. The organs inside the abdomen are covered by a thin lining called the peritoneum. This lining helps protect the abdominal organs and allows them to move smoothly.

In PMP, mucus-producing cells from an appendix tumour can spread inside the abdominal cavity, often after the appendix or tumour ruptures. These cells continue to make a thick, jelly-like substance called mucin. Over time, this mucin can collect inside the abdomen and coat the lining of the abdominal cavity and the surface of nearby organs.

PMP does not always spread like many other cancers. In many cases, it tends to spread within the abdomen rather than travelling through the bloodstream to distant organs such as the lungs or liver. As mucin builds up, it can cause symptoms such as increasing abdominal size, bloating, abdominal discomfort, hernia, changes in bowel habits, or bowel blockage in advanced cases.

Treatment for PMP depends on how much disease is present, the tumour grade, the patient’s overall health, and whether the disease can be removed safely. For selected patients, doctors may consider cytoreductive surgery, also called CRS, with HIPEC. CRS is surgery to remove visible tumour and mucin from the abdomen. HIPEC is heated chemotherapy given directly inside the abdomen during surgery to help treat remaining cancer cells.

Doctors may also use a scoring system called the Peritoneal Cancer Index, or PCI, to understand how widely the disease has spread inside the abdomen. The abdomen is divided into 13 areas, and each area is scored based on the size of tumour deposits. A higher PCI score usually means the disease is more extensive and the surgery may be more complex.

One of the most important goals of treatment is complete cytoreduction, which means removing all visible disease where possible. Patients with PMP should ideally be evaluated at a specialist centre experienced in appendix cancer, peritoneal surface malignancies, CRS, and HIPEC. This helps ensure accurate staging, careful treatment planning, and a realistic understanding of expected outcomes.

Why Appendix Cancer Can Look Like Appendicitis

Appendix cancer can be mistaken for appendicitis because both conditions may cause similar symptoms, such as pain in the lower right side of the abdomen, nausea, bloating, or changes in bowel habits. Since appendicitis is much more common, doctors may first suspect and treat it as appendicitis, especially during an emergency.

In many cases, appendix cancer is found only after the appendix has been removed and tested in a laboratory. This test is called a histopathology examination, where the removed appendix is checked under a microscope. Sometimes, this report shows an unexpected tumour.

This is why the pathology report after appendix surgery is important. If a tumour is found, the patient may need further tests and review by a specialist cancer team. This does not always mean the cancer has spread, but it helps doctors decide the right next steps.

Some appendix tumours produce mucus. If such a tumour leaks or ruptures, mucus-producing cells may spread inside the abdomen. In rare cases, this can lead to a condition called pseudomyxoma peritonei, or PMP, where jelly-like fluid slowly builds up in the abdomen. Early specialist review can help reduce the risk of missed or delayed treatment.

In women, appendix cancer can sometimes look like a gynaecological problem because it may appear as a pelvic or ovarian mass. In some cases, the appendix is later found to be the original source. This is why accurate testing, staging, and specialist review are important after an unusual appendix finding.

Signs and Symptoms of Appendix Cancer

Appendix cancer often does not cause clear symptoms in the early stages. Many people feel well, and the cancer is found unexpectedly during surgery, imaging, or tests done for another abdominal problem.

When symptoms do appear, they are often vague and can look like more common conditions such as appendicitis, irritable bowel syndrome, stomach infection, or gynaecological problems. This is one reason appendix cancer can be difficult to recognise early.

Symptoms may include:

• Right lower abdominal pain or discomfort: Pain may occur on the lower right side of the abdomen, similar to appendicitis. In some people, it may be mild, on and off, or mistaken for gas, acidity, IBS, or muscle strain.
• Abdominal bloating or swelling: A gradual increase in abdominal size that does not seem related to diet or weight gain may need medical evaluation. In some cases, this can happen when mucus-like fluid collects inside the abdomen, as seen in pseudomyxoma peritonei, or PMP.
• Pelvic or ovarian mass in women: In some women, appendix cancer may first appear as a pelvic or ovarian mass on ultrasound or examination. This can sometimes be mistaken for an ovarian cyst or ovarian cancer.
• Changes in bowel habits: Persistent constipation, diarrhoea, change in stool pattern, or a feeling that the bowel is not emptying properly should be checked if it does not improve or has no clear cause.
• Hernia: In some cases, appendix cancer or PMP may be found during evaluation or surgery for an inguinal or umbilical hernia.
• General symptoms in advanced disease: Some people may experience tiredness, nausea, feeling full after eating very little, loss of appetite, or unexplained weight loss.

These symptoms do not always mean appendix cancer. However, if you have persistent right lower abdominal pain, unexplained abdominal swelling, a pelvic mass, or ongoing digestive changes, it is important to speak to a doctor. If you have had appendicitis, appendix surgery, or an unexpected pathology report in the past, make sure to share that history during your consultation.

How is Appendix Cancer Diagnosed?

Appendix cancer is often diagnosed in one of two ways. In some people, it is found unexpectedly after the appendix is removed for suspected appendicitis. In others, it is suspected after symptoms, an imaging scan, or a finding such as an abdominal or pelvic mass.

Once appendix cancer is suspected, doctors may use a combination of tests to understand the type of tumour, whether it has spread, and what treatment may be needed.

• Histopathology: This is the examination of removed tissue under a microscope. Many appendix cancers are first confirmed when the appendix is sent for pathology testing after surgery. The pathology report helps identify the type of tumour, its grade, and whether further treatment or specialist review is needed.
• CT scan: A CT scan of the chest, abdomen, and pelvis is commonly used to look for the tumour and check whether the disease has spread. In cases of pseudomyxoma peritonei, or PMP, CT may show mucus-like deposits inside the abdomen or pressure changes on nearby organs.
• MRI: MRI may be used when doctors need a more detailed view of disease inside the abdomen. It can help assess peritoneal disease, which means disease affecting the lining of the abdominal cavity. MRI may also help with treatment planning before cytoreductive surgery and HIPEC.
• PET-CT: PET-CT is not required for every patient. It may be used selectively, especially in more aggressive tumour types, to check for disease activity or spread beyond the abdomen.
• Tumour marker blood tests: Blood tests such as CEA, CA 19-9, and CA-125 may be checked in some appendix cancers. These tests do not confirm appendix cancer on their own, but they can help doctors assess the disease, plan treatment, and monitor response or recurrence after treatment.
• Colonoscopy: A colonoscopy may be advised to examine the large intestine, especially the caecum, which is the part of the colon near the appendix. It also helps doctors check whether there is another tumour in the colon.
• Biopsy: In selected cases, if imaging suggests PMP or cancer spread inside the abdomen but tissue confirmation is still needed, doctors may take a biopsy before planning treatment.

Before major treatments such as cytoreductive surgery and HIPEC, doctors also assess the patient’s overall health, organ function, fitness for surgery, and the extent of disease inside the abdomen. This helps the specialist team decide whether surgery is possible, how complex it may be, and what recovery may involve.

How is Appendix Cancer Treated?

Treatment for appendix cancer depends on the type of tumour, how far it has spread, and the patient’s overall health. Doctors also look at whether the disease has spread inside the abdomen and, in some cases, use a score called the Peritoneal Cancer Index, or PCI, to understand how extensive it is.

At RGCIRC, appendix cancer cases are reviewed by the GI and HPB Tumour Board, where specialists from different departments come together to plan the most suitable treatment approach. This may include surgical oncologists, medical oncologists, radiation oncologists, radiologists, pathologists, and other members of the cancer care team.

Surgery

Surgery is the main treatment for many appendix cancers, but the type of surgery depends on the tumour.

For small, well-differentiated neuroendocrine tumours of the appendix, sometimes called carcinoid tumours, removal of the appendix may be enough if the tumour is small and has low-risk features.

For appendix adenocarcinoma that has not spread widely, doctors may advise a right hemicolectomy. This surgery removes the right side of the colon along with nearby lymph nodes so the cancer can be treated and staged properly.

For mucinous appendix cancer or pseudomyxoma peritonei, also called PMP, that has spread inside the abdominal cavity, doctors may consider cytoreductive surgery, or CRS. This is a major operation in which the surgeon removes visible tumour deposits and mucin from the abdomen. The aim is to remove as much visible disease as possible.

HIPEC

HIPEC stands for hyperthermic intraperitoneal chemotherapy. It is a specialised treatment that may be given during surgery in selected patients with disease spread inside the abdomen.

After the visible tumour has been removed through cytoreductive surgery, heated chemotherapy is circulated directly inside the abdominal cavity. The purpose is to target cancer cells that may be too small to see or remove during surgery.

HIPEC is not suitable for every patient. Doctors decide whether it is appropriate based on the cancer type, tumour grade, extent of disease, PCI score, fitness for surgery, and whether complete removal of visible disease appears possible.

Systemic Chemotherapy, Targeted Therapy and Immunotherapy

Some patients may need medicines that work throughout the body. This is called systemic treatment.

Systemic chemotherapy may be used in more aggressive appendix cancers, such as non-mucinous adenocarcinoma, goblet cell carcinoma, signet ring cell carcinoma, or cancer that has spread beyond the appendix. It may be given before or after surgery, or as the main treatment when surgery is not possible.

Molecular profiling may also be advised in advanced disease. This test looks for specific changes in the cancer cells that may help guide treatment. In selected patients, targeted therapy or immunotherapy may be considered, especially when the tumour has certain markers such as MSI-H or mismatch repair deficiency.

Because appendix cancer is rare and treatment can be complex, it is important to be evaluated by an experienced GI oncology team. The right treatment plan depends on careful diagnosis, accurate staging, and discussion by a multidisciplinary cancer team.

Why Choose RGCIRC for Appendix Cancer Treatment?

Appendix cancer is rare, and its treatment can be complex, especially when it is linked with pseudomyxoma peritonei, or PMP. Patients may need care from a team that understands gastrointestinal cancers, peritoneal spread, cytoreductive surgery, HIPEC, chemotherapy, and molecular testing. At RGCIRC, appendix cancer care is planned through a multidisciplinary approach so that each patient receives a treatment plan based on the exact type and stage of disease.

Dedicated GI Oncosurgery and HPB Expertise

RGCIRC has a dedicated GI Oncosurgery and Hepato-Pancreato-Biliary, or HPB, programme for gastrointestinal cancers. Complex cases are reviewed by the GI and HPB Tumour Board, where surgical oncologists, medical oncologists, radiation oncologists, radiologists, pathologists, and other specialists discuss the case together.

For a rare disease like appendix cancer, this team-based review is important. It helps doctors decide whether the patient needs surgery, HIPEC, chemotherapy, molecular testing, or a combination of treatments.

CRS and HIPEC Programme

RGCIRC offers cytoreductive surgery, or CRS, with HIPEC for selected patients with peritoneal malignancies, including appendiceal mucinous tumours and PMP.

CRS and HIPEC are specialised treatments used when cancer or mucin-producing cells have spread inside the abdominal cavity. These procedures require trained surgical teams, dedicated equipment, and careful post-operative care. For patients in Delhi NCR and North India, access to this treatment at a specialist cancer centre can be an important part of care planning.

Molecular Testing and Precision Oncology

RGCIRC has an NABL-accredited next-generation sequencing, or NGS, molecular laboratory for tumour profiling. In appendix cancer, molecular testing may help identify markers such as MSI-H status, KRAS mutations, BRAF mutations, and other actionable changes.

This information can help doctors understand whether a patient may benefit from targeted therapy, immunotherapy, or other personalised treatment options, especially in advanced or complex cases.

Accreditations and Recognised Excellence

RGCIRC holds NABH accreditation, NABL laboratory accreditation, NABH Green OT certification, and NABH Nursing Excellence certification.

The institute has also been recognised among Newsweek’s World’s Best Specialised Hospitals in 2024 and 2025. It was ranked No. 1 in North India as a single-specialty hospital by the Times of India in 2025 and was awarded Best Oncology Hospital of the Year 2026 by the IHW Council.

These accreditations and recognitions reflect RGCIRC’s focus on clinical quality, patient safety, and specialised cancer care.

Commitment to Accessible Cancer Care

RGCIRC is a not-for-profit cancer institute founded in 1996 with the aim of making quality cancer care more accessible and affordable. Since its inception, more than 3.5 lakh patients have been treated at the institute.

For patients and families facing a rare cancer diagnosis, this commitment matters. It means care is not only focused on advanced treatment, but also on guidance, support, and access to specialised cancer services.

Final Words

Appendix cancer is rare and often found unexpectedly. Many people are diagnosed only after surgery for suspected appendicitis, an imaging scan, or a pathology report that shows something unusual. Because this cancer is uncommon, reaching the right specialist at the right time is important.

If your appendix has been removed and the pathology report mentions a mucinous tumour, LAMN, appendix tumour, or any finding beyond simple appendicitis, it is important to get the case reviewed by a GI oncology specialist. Routine surgical follow-up may not be enough in such cases.

If you have been diagnosed with pseudomyxoma peritonei, or PMP, you may need evaluation at a centre experienced in cytoreductive surgery, also called CRS, and HIPEC. These treatments are specialised and are considered for selected patients when disease has spread inside the abdominal cavity.

Appendix cancer and PMP can feel overwhelming at first, but the right evaluation can help patients and families understand the diagnosis, treatment options, and next steps more clearly. Early diagnosis, accurate staging, and care from an experienced cancer team can make an important difference.

To speak with the GI Oncosurgery team at RGCIRC, book an appointment online at care.rgcirc.org.

Call us:
+91-11-4702 2222, Rohini, North Delhi
+91-11-4582 2222, Niti Bagh, South Delhi

OPD hours: Monday to Saturday, 9:00 AM to 5:00 PM
Emergency services: Available 24×7 at both campuses

Download the RGCI Care app on iOS and Android.

FAQs

What is Appendix Cancer Awareness Month?

Appendix Cancer Awareness Month is observed every August to raise awareness about appendix cancer and pseudomyxoma peritonei, also called PMP. It is represented by the amber ribbon and supported by the ACPMP Research Foundation, which was founded in 2008 to support research, education, and better treatment for appendix cancer and PMP.

What are the symptoms of appendix cancer?

Appendix cancer may not cause clear symptoms in the early stages. When symptoms do appear, they can include pain or discomfort in the lower right side of the abdomen, bloating, swelling of the abdomen, changes in bowel habits, nausea, loss of appetite, feeling full after eating very little, fatigue, or unexplained weight loss.

In women, appendix cancer may sometimes appear as a pelvic or ovarian mass on imaging. Many people are diagnosed unexpectedly after appendix surgery, a scan, or tests done for another abdominal problem.

Is appendix cancer the same as colon cancer?

No. Appendix cancer is not the same as colon cancer, even though the appendix is attached to the large intestine. Some appendix cancers produce a jelly-like substance called mucin and may spread inside the abdominal cavity rather than spreading like typical colon cancer. Because of this, treatment may also be different, especially when pseudomyxoma peritonei, or PMP, is present.

What is pseudomyxoma peritonei, or PMP?

Pseudomyxoma peritonei, or PMP, is a rare condition in which mucus-producing tumour cells spread inside the abdominal cavity and produce a jelly-like substance called mucin. This mucin can slowly build up around the abdominal organs and cause bloating, abdominal swelling, discomfort, digestive symptoms, or bowel blockage in advanced cases.

PMP most commonly starts from a mucin-producing tumour of the appendix. In selected patients, treatment may include cytoreductive surgery, also called CRS, with HIPEC at a specialist cancer centre.

What is HIPEC and how does it treat appendix cancer?

HIPEC stands for hyperthermic intraperitoneal chemotherapy. It is a specialised treatment used in selected patients when appendix cancer or PMP has spread inside the abdominal cavity.

HIPEC is usually given during surgery after the surgeon removes visible tumour and mucin through cytoreductive surgery. Heated chemotherapy is circulated directly inside the abdomen to help treat cancer cells that may be too small to see or remove. HIPEC is available at RGCIRC for selected patients with peritoneal spread.

Can appendix cancer be cured?

In some patients, appendix cancer can be treated with curative intent. The chances depend on the tumour type, grade, stage, disease spread, and whether all visible disease can be removed.

Small, low-risk neuroendocrine tumours of the appendix may be treated successfully with appendix removal alone. For PMP or mucinous appendix cancer with spread inside the abdomen, long-term disease control may be possible in selected patients with cytoreductive surgery and HIPEC. Your doctor can explain the expected outcome based on your exact diagnosis.

Is appendix cancer hereditary?

Most appendix cancers are not hereditary. They usually occur without a clear inherited cause. However, a small number of cases may be linked with inherited cancer syndromes such as Lynch syndrome, which can increase the risk of some gastrointestinal cancers.

If you have a strong family history of colorectal, endometrial, or other related cancers, speak to your oncologist about whether genetic counselling is needed. RGCIRC offers genetic counselling as part of its cancer care services.

How is appendix cancer different from appendicitis?

Appendicitis is inflammation or infection of the appendix. Appendix cancer is abnormal cell growth that starts in the appendix.

The two can cause similar symptoms, such as pain in the lower right side of the abdomen, nausea, vomiting, or fever. This is why appendix cancer is sometimes found only after the appendix is removed for suspected appendicitis and the tissue is checked under a microscope.

If the pathology report shows a mucinous tumour, LAMN, appendix tumour, or any finding beyond simple appendicitis, the case should be reviewed by a GI oncology specialist.