• This manual is not a substitute for consultation with an appropriate specialist.
• The contents of this manual have been developed through consensus of a Provincial Tumour Group. Please note the various update dates for each section as some of the content of the manual may not be up to date.

Updated 29 November 2021

This section addresses epithelial tumours arising from the appendix.

For treatment of appendiceal neuroendocrine tumours (i.e. carcinoid), please refer to the Neuroendocrine section

Updated 19 February 2013

Due to the rarity of malignancies arising from the appendix, there are no recommended screening guidelines. 

Added 06 March 2013

Cancer of the appendix is rare, accounting for about 1% of all colorectal tumours, or less than 1000 cancers a year across Canada. Cancer of the appendix is typically classified by the type of cells found within the tumour. Roughly half of all appendix cancers are neuroendocrine or carcinoid tumours and are discussed in the “Neuroendocrine” section. The remaining tumour types largely arise from epithelial cells and are classified as follows:

• Mucinous cystadenoma and cystadenocarcinoma
• Goblet cell carcinoma (adenocarcinoid)
• Adenocarcinoma, which are divided into three subtypes
  • mucinous
  • colonic-type
  • signet ring

Pseudomyxoma Peritonei (PMP)

PMP is a term used to describe the clinical syndrome that arises from perforation of an appendiceal tumour and subsequent seeding of tumour cells within the peritoneal cavity. Though it has been used to describe intraperitoneal mucinous dissemination from various tumours in the appendix, and other organs, it was originally intended to describe disease that stemmed from a cystadenoma of the appendix only.

PMP should be limited to the description of more indolent disease processes associated with mucinous carcinomatosis.

Although consistency is lacking in the literature with regards to the use of terms such as disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous carcinomatosis (PMCA), some centres use a simpler scheme separating cases in low grade appendiceal mucinous neoplasms (LAMN) and high grade mucinous adenocarcinoma (MACA). This is more useful terminology as it reflects the expect behaviour of these tumour which may help guide management.

Added 06 March 2013

Appendiceal cystadenomas and cystadenocarcinomas are often found incidentally at the time of appendectomy or on CT imaging done for other reasons. Patients with goblet cell carcinomas most often present with acute or chronic abdominal pain. Patients with any of these appendiceal tumours can present with symptoms of acute appendicitis or chronic right lower quadrant pain. Patients with pseudomyxoma peritonei may be found incidentally at laparotomy, or present with increasing abdominal girth, inguinal hernia in men, or palpable ovarian mass in women.​

In terms of a diagnostic work up, a CT scan of the abdomen and pelvis should be done to assess the extent of peritoneal and nodal involvement. Because of the high incidence of associated colonic neoplasms, colonoscopy is recommended at diagnosis in all patients. Imaging of the chest should be done if intra-abdominal metastases are found. Image guided percutaneous biopsy of the thickened peritoneum or the omentum can be used for diagnostic purposes. PET scans are not recommended for staging purposes. Pre-operative tumour markers carcinoembryonic antigen (CEA), CA 19-9 and CA-125 may be useful for future monitoring.​

Given the rarity of these cancers, referral to BCCA is recommended.

Patients with simple node-negative cystadenomas do not require adjuvant therapy and can be followed by their surgeon.

Added 06 March 2013

• Standard appendectomy is adequate for simple cystadenomas.
• Patients found unexpectedly at the time of laparotomy or laparoscopy to have a mucinous appendiceal tumour should simply have an appendectomy. More extensive surgery (right hemicolectomy, omentectomy etc) increases the technical difficulty of the subsequent definitive operation without any acute benefit to the patient.
  • Right hemicolectomy is indicated for:
  • complicated cystadenomas with involvement of the terminal ileum or cecum
  • goblet cell carcinomas - especially those that are greater than 2 cm, involve the base of the appendix, associated with nodal metastases, or have atypical histology.
• any appendiceal adenocarcinoma or cystadenocarcinoma.
• Surgical debulking is the recommended approach for symptomatic DPAM
• Aggressive cytoreductive surgery with intraperitoneal chemotherapy may be considered in selected patients with intraperitoneal disease at specialized surgical centres. Referral to the BCCA for multidisciplinary assessment is recommended.​

Added 06 March 2013

All cases considered for HIPEC need to be reviewed in a multidisciplinary tumour conference.

HIPEC is not an option in the following cases:

Absolute contraindications

• ECOG > 2
• Non appendiceal/colorectal/mesothelial primary
• Unresectable disease on preoperative imaging
• Extra-abdominal metastases
• Multifocal malignant small bowel obstruction
• Co-morbidities precluding extensive surgery (renal failure, cardiac disease, COPD, other)

Relative contraindications

• Age >70 years
• Extensive disease not amenable for R0/1 resection
• Synchronous liver metastases
• Progression while on chemotherapy
• High-grade adenocarcinoma
• Sarcomatoid variant of peritoneal mesothelioma
• Bilateral hydronephrosis

Added 06 March 2013

 (per College of American Pathologists 2012)

Specimen: specify

• Type
  
• Procedure
• Length
• Integrity

Tumour: specify

• Site
• Size
• Histologic type
• Histologic grade
• Microscopic tumour extension
• Margins: proximal, distal, mesenteric, circumferential
• Lymph nodes: number examined, number involved
• Lymph-Vascular invasion
• Perineural invasion
• Satellite peritumoral nodules (tumour deposits)
• pTNM per AJCC 7^th Edition

Additional pathologic findings of interest

Added 26 March 2013

Staging Diagram and Classification Criteria (TNM)​

Added 06 March 2013

Treatment Options by Histologic Subtype:

Due to the rarity of these tumours, clinical trials are lacking, and most treatments are based on consensus opinion.

Mucinous Cystadenoma

Standard appendectomy with resection of the appendiceal mesentery is adequate surgery for a cystadenoma that shows no sign of mesenteric involvement or extension to adjacent organs. Patients found unexpectedly at the time of laparotomy or laparoscopy to have a mucinous appendiceal tumour should simply have an appendectomy. More extensive surgery (right hemi, omentectomy etc) increases the technical difficulty of the subsequent definitive operation without any acute benefit to the patient. There is no role for chemotherapy or radiation therapy with these tumours.

Pseudomyxoma peritonei

Special consideration should be given for cytoreductive surgery and intraperitoneal chemotherapy in patients with PMP. Repeat surgical debulking can be used for symptom control. For patients of lower functional status consideration should be given to best supportive care and hospice referral.

Goblet cell carcinoma

Stage I tumours can be treated with appendectomy alone, while higher stages of disease should be treated with right hemicolectomy to permit adequate nodal sampling. There is no data to support the role of adjuvant systemic therapy. In the metastatic setting typical regimens used to treat colon adenocarcinoma, such as FOLFOX and FOLFIRI chemotherapy have been suggested. In selected cases with peritoneal disease, cytoreductive surgery and intraperitoneal chemotherapy could be considered in specialized surgical centres. Long term prognosis with metastatic disease is poor and consideration should be given to best supportive care with referral to hospice.

​Adenocarcinoma (mucinous, colonic-type, signet ring) and Cystadenocarcinoma

Right hemicolectomy is suggested for adenocarcinoma and cystadenocarcinoma in order to determine nodal status and should follow standard procedures as for colorectal cancer. Adjuvant, 5-FU based chemotherapy is suggested for node positive disease, based on extrapolated colon cancer data. In the metastatic setting with peritoneal disease, cytoreductive surgery and intraperitoneal chemotherapy should be considered in highly selected patients at specialized surgical centres. Otherwise palliative chemotherapy, as in colon cancer, should be considered. For patients of lower functional status, best supportive care and hospice referral should be pursued. 

Added 06 March 2013

Patients Treated with Curative Intent

Due to the rarity of malignancies arising from the appendix, there are no recommended surveillance guidelines. However, these patients are at risk of peritoneal dissemination. Early diagnosis when limited disease is presence is more likely to result in complete cytoreduction and prolonged survival especially for patient with low grade disease. Consideration should be given for serial follow-up imaging.​