What are the other Names for this Condition? (Also known as/Synonyms)

• Appendiceal Mucinous Adenocarcinoma
• Appendicular Mucinous Adenocarcinoma
• Primary Appendiceal Mucinous Adenocarcinoma

What is Mucinous Adenocarcinoma of Appendix? (Definition/Background Information)

• Mucinous Adenocarcinoma of Appendix is a rare histological subtype of appendiceal adenocarcinoma. The appendix is a small blind pouch of the colon, located at the beginning of the colon (large intestine)
• The tumor is diagnosed under a microscope, on examination of the cancer cells by a pathologist, and may be classified into the following grades:
  • Low-grade Mucinous Adenocarcinoma of Appendix
  • High-grade Mucinous Adenocarcinoma of Appendix
• The subtype is denoted based on the predominant histologic pattern observed (presence of mucinous component). This classification of the tumor is important, as it may dictate the type of treatment to be provided and its prognosis
• Mucinous Adenocarcinoma of Appendix is typically observed in middle-age and older adults. The cause of formation of the carcinoma is believed to be associated with genetic defects and certain food and lifestyle factors. The carcinoma may also develop when it is associated with certain genetic disorders (such as familial adenomatous polyposis)
• The signs and symptoms may mimic that of acute appendicitis, such as severe abdominal pain, appetite loss, nausea and vomiting, and unintended weight loss. Complications, such as tumor metastasis to distant sites, are known to occur
• The mainstay of treatment is surgical excision of the tumor, during the early stages. However, in many cases a combination of treatment measures that include surgery, chemotherapy, and radiation therapy may be required
• The prognosis of Mucinous Adenocarcinoma of Appendix is generally improved, if the tumor is diagnosed early and treated accordingly. However, a delay in diagnosing the condition can affect the prognostic values adversely

Who gets Mucinous Adenocarcinoma of Appendix? (Age and Sex Distribution)

• Mucinous Adenocarcinoma of Appendix is a rare carcinoma that may constitute over 50% of all appendiceal adenocarcinomas
• It is generally seen in middle-aged and older adults with a mean age of 50 years
• When children and/or young adults are affected, it is mostly seen in the background of a predisposing (genetic) factor
• Both males and females are affected, although 80% of the cases are reportedly observed in males
• All races and ethnic groups are at risk for the condition

What are the Risk Factors for Mucinous Adenocarcinoma of Appendix? (Predisposing Factors)

The following factors may increase the risk for Appendiceal Mucinous Adenocarcinoma:

• Aging: The greater the age, the higher is the risk for gastrointestinal tract carcinomas, in general
• Presence of premalignant lesions: The carcinoma may occur from precursor lesions/adenomas, which may be low-grade or high-grade
• Chronic inflammatory bowel disorders, such as ulcerative colitis, which are longstanding
• Presence of a genetic disorder such as
  • Familial adenomatous polyposis (FAP); many tumors have been associated with FAP
  • Lynch syndrome or hereditary nonpolyposis colorectal cancer (HNPCC)
  • Polyposis syndrome

A few other risk factors for intestinal adenocarcinomas may include:

• Consuming a high calorie diet
• Meat consumption (including animal fat) and sedentary lifestyle
• Alcohol consumption
• Obesity
• Radiation therapy to the pelvic region for cancer
• Procedure for bladder cancer treatment called ureterosigmoidostomy
• Smoking tobacco may increase the risk

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Mucinous Adenocarcinoma of Appendix? (Etiology)

The cause of development of Mucinous Adenocarcinoma of Appendix is generally unknown. Some reports indicate that it is seen in the background of colonic neoplasia that may be present anywhere in the bowel/intestine.

• Research scientists believe that the cause of the condition is mostly due to genetic mutations, influenced by lifestyle factors that may include high-fat, high-calorie diet and sedentary lifestyle
• Research studies indicate that both mucinous carcinomas and non-mucinous carcinomas show similar genetic abnormalities in many cases
• Some Appendiceal Mucinous Adenocarcinomas exhibit high levels of microsatellite instability (MSI-H), which may be due to an association with a genetic disorder such as Lynch syndrome. Abnormalities in the DNA mismatch repair pathway have been noted that may lead to decreased functioning of certain proteins (DNA repair proteins)
• The genetic factors reported for appendiceal adenocarcinomas include:
  • Loss of heterozygosity (LOH) involving chromosome 18
  • Gene mutations involving SMAD4 or DPC4 genes, in some cases
  • Most tumors, whether mucinous or non-mucinous, are reportedly microsatellite stable (a measure of the relative risk for gene mutation). Rarely, they display microsatellite-instability
  • Involvement of the CTNNB1 gene is not seen in any adenocarcinoma of appendix, unlike many other intestinal adenocarcinomas

What are the Sign and Symptoms of Mucinous Adenocarcinoma of Appendix?

In some individuals, Mucinous Adenocarcinoma of Appendix is detected while conducting diagnostic imaging tests for other medical conditions, since no symptoms may be observed. In a few cases, it may detected following a surgical removal of the appendix (appendectomy), undertaken for appendicitis.

In others, the signs and symptoms of Appendiceal Mucinous Adenocarcinoma may include:

• Symptoms that are similar to acute appendicitis such as:
  • Abdominal pain that first originates around the umbilicus and then gradually moves towards a point on the right lower quadrant of the abdomen, called the McBurney’s point
  • Sometimes, the pain can occur anywhere in the upper or lower abdomen, back, or rectum
  • Nausea and vomiting
  • In some, fever, shivering, and chills may be observed
  • Loss of appetite
  • Constipation or diarrhea
  • Occasionally, painful urination and severe cramps can occur
• The pain may be present for a long duration of time
• Presence of an abdominal mass with abdominal tenderness
• Swollen appendix
• Ulceration of the tumor, especially when it is large
• Rarely, it can cause narrowing of the colon
• Passing of fresh blood in stool (hematochezia) and anemia is observed, if the tumor is bleeding
• Sometimes, perforation of the intestinal walls may occur
• Fever, unintended weight loss and fatigue/tiredness
• Large tumors can deform the appendix to a great extent, and sometimes even obliterate it

How is Mucinous Adenocarcinoma of Appendix Diagnosed?

A diagnosis of Mucinous Adenocarcinoma of Appendix may be undertaken using the following tests and exams:

• Complete evaluation of family (medical) history, along with a thorough physical examination
• Stool sample analysis
• Complete blood count (CBC)
• Basic metabolic panel
• X-ray of abdomen
• Ultrasound scan of abdomen or abdomino-pelvic CT scan
• Screening colonoscopy: A colonoscopy is a test that allows the physician to look at the inner lining of the colon and rectum. A typical colonoscopy involves using a thin, flexible tube (called a colonoscope), with an attached video camera, to view the colon and rectum
• Lower gastrointestinal series, which are a combination of analysis methods, combining X-rays and barium to visualize the intestinal region
• Imaging studies, such as MRI scan, transrectal ultrasound scan (TRUS), scintigraphy, and PET scan, may be performed to detect tumor invasion and metastasis
• Tissue biopsy of the tumor:
  • A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
  • Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
  • Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely, electron microscopic studies to assist in the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Mucinous Adenocarcinoma of Appendix?

Some potential complications of Mucinous Adenocarcinoma of Appendix include:

• Emotional and psychological stress due to cancer diagnosis
• High-grade tumors (such as mucinous adenocarcinomas) can cause pseudomyxoma peritonei. Due to this there is an increase in mucus secretion, leading to swollen abdomen or consequently hernia
• Tumor infiltration to adjacent abdominal and pelvic organs, such as intestines, urinary bladder, vagina, or ovary may be noted
• Metastasis to local and regional sites; spread of tumor to the lymph nodes. The tumor metastasizes through the vascular and lymphatic system
• Recurrence of the tumor after treatment, especially due to partial surgical removal
• Side effects due to cancer therapy

How is Mucinous Adenocarcinoma of Appendix Treated?

The treatment of Mucinous Adenocarcinoma of Appendix may depend upon a consideration of the following set of factors:

• Stage of the cancer
• Size and location of the tumor
• Severity of the signs and symptoms
• Age of the individual
• Overall health status of the individual
• The treatment preferences of the individual

The treatment measures for Mucinous Adenocarcinoma of Appendix may include:

• Surgical removal of the entire tumor may be the preferred method of treatment
  • Open appendectomy: It involves making a deep incision on the lower abdomen and removing the appendix from the surrounding abdominal organs
  • In laparoscopic appendectomy, a surgeon makes 3 or 4 small incisions for insertion of the camera and the laparoscopic instruments and the appendix is cut and removed
  • Right hemicolectomy, if necessary, which is the partial removal of the affected portion of the colon (on the right side), along-with the tumor. This is considered an optimal treatment, if metastasis has not taken place
• Chemotherapy: This approach uses a combination of drugs to kill the cancerous cells and can be used in patients, for all stages of the tumor
  • There can be severe side effects including fatigue, nausea, hair loss, anemia, high risk of infection, and drug-specific reactions
  • Chemotherapy can be administered as a pill, liquid, shot, or intravenously
• Radiation: Radiation therapy is the use of high-energy radiation waves to kill cancer cells, by destroying their DNA
  • This treatment modality may be used in combination with chemotherapy
  • The radiation may be administered by a machine placed outside the body, or by placing a radioactive material inside the body
  • The side effects of radiation therapy include nausea, vomiting, fatigue, pain, risk of cancer later in life, and risk of heart disease
  • Radiation can damage healthy cells in addition to cancer cells, causing further complications
• Supportive treatment: Steroids, blood transfusions, anti-nausea medications, and antibiotics, may be used as supportive therapy. In combination with other treatment measures, these can help combat the symptoms of immunodeficiency
• Undertaking treatment of underlying inflammatory bowel diseases/genetic disorders, as necessary
• Targeted drug therapy: Specific medications are administered periodically to stop tumor growth, particularly for advanced stages
• Immunotherapy: A patient’s immune system is activated to combat the cancer in this kind of therapy

Regular observation and periodic checkups to monitor the condition is strongly recommended following treatment.

How can Mucinous Adenocarcinoma of Appendix be Prevented?

Presently, there are no specific methods or guidelines to prevent the formation of Mucinous Adenocarcinoma of Appendix. However, if it is associated with a genetic disorder, the following points may be considered:

• Genetic counseling and testing: If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Regular health check-ups might help those individuals with a history of the condition in the immediate family and help diagnose the tumor early

Factors that can help prevent or reduce incidence of gastrointestinal carcinomas may include:

• Undergoing routine colonoscopy screenings, for individuals over the age of 45-50 years, to ensure early detection of colon tumors or cancers
• Consuming a diet that is rich in whole grains, vegetables, and fruits
• Taking foods rich in vitamin D and calcium
• Physical activities and regular exercising
• Taking early and appropriate treatment for inflammatory bowel diseases, if any
• In order to avoid a relapse, or be prepared for a recurrence, the entire diagnosis, treatment process, drugs administered, etc. should be well-documented and follow-up measures initiated

Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory. Often several years of active vigilance are crucial and necessary.

What is the Prognosis of Mucinous Adenocarcinoma of Appendix? (Outcomes/Resolutions)

With prompt diagnosis and appropriate treatment, Mucinous Adenocarcinoma of Appendix the prognosis may be improved. The overall 5-year survival rate based on certain studies is between 20-45% for the mucinous adenocarcinoma subtype.

• In general, adenocarcinomas that are confined to the mucosal surfaces and fully (surgically) removed, show very low risk for metastasis, even when invasion is seen into the intramucosal areas
• In general, the prognosis depends upon a set of several factors, which include: 
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually excellent with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • The size of the tumor: Individuals with small-sized tumors fare better than those with large-sized tumors
  • Histological subtype of the tumor; mucinous tumors reportedly have better outcomes than non-mucinous tumors
  • Whether the tumor is low-grade or high-grade; high-grade tumors have poorer outcomes
  • Individuals with bulky disease have a poorer prognosis
  • Involvement of vital organs may complicate the condition
  • The surgical resectability of the tumor (meaning, if the tumor can be removed completely)
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
  • Progression of the condition makes the outcome worse
• The combination chemotherapy drugs used, may have some severe side effects (such as cardio-toxicity). This chiefly impacts the elderly adults, or those who are already affected by other medical conditions. Tolerance to the chemotherapy sessions is a positive influencing factor

An early diagnosis and prompt treatment of Mucinous Adenocarcinoma of Appendix generally yields better outcomes than a late diagnosis and delayed treatment.

Additional and Relevant Useful Information for Mucinous Adenocarcinoma of Appendix:

The following article link will help you understand other cancers and benign tumors:

http://www.dovemed.com/diseases-conditions/cancer/