Peritoneal Cancer

Overview

The peritoneum is a layer of tissue found in the abdomen (abdomen). The inner layer covers the surface of all abdominal organs, including the stomach, liver, and intestines. The outer layer forms the abdominal wall. Primary peritoneal cancer occurs when cancer begins in the peritoneum.

What is Peritoneal Cancer?

Peritoneal malignancy or peritoneal cancer(PC)  refers to the invasion of malignant cells into the serous membrane lining the abdominal cavity, viscera, and coelom in amniotes . It is classified as primary or secondary.

Primary peritoneal cancer (PPC) is a relatively uncommon malignancy that mostly affects women. PPC is a close cousin of epithelial ovarian cancer, which is the most frequent kind of ovarian cancer. The origin of primary peritoneal cancer is unknown, however women should be aware that it is possible to get primary peritoneal cancer even after their ovaries have been removed.

Researchers categorised primary cancer based on its histology. The first form is known as extraovarian primary peritoneal carcinoma (EOPPC), serous surface papillary carcinoma, papillary serous carcinoma of the peritoneum, extraovarian Mullerian adenocarcinoma, and normal-sized ovarian cancer syndrome.

Secondary or metastatic peritoneal carcinomatosis is frequently caused by primary malignancies of the gastrointestinal and gynecological systems. The metastases takes place via transcoelomic, vascular, or lymphatic pathways. It was initially characterized as a local spread from ovarian cancer in 1931.

Primary cancer is classified as stage III or IV, whereas metastasis is classified as stage IV. The hazy clinical presentation is to blame for late diagnosis and a reduction in overall survival. Surgical excision and intraperitoneal chemotherapy are distinguishing features of disease eradication. However, advances in technology and a better knowledge of peritoneum physiology and tumor seeding pathways have resulted in the creation of viable therapeutic regimens. In the absence of substantial systemic illness, locoregional disease control may play a potential role in the treatment of this late-stage malignancy.

Types of primary peritoneal cancer

Epithelial

Epithelial carcinoma is the most prevalent type of cancer that begins in the peritoneum. It begins in epithelial cells and has several subtypes. The most prevalent type of cancer is serous cancer. They are generally of good quality, which allows them to develop more swiftly.

Other much less common types are:

• Clear cell
• Endometrioid
• Mucinous.

These are more likely to be diagnosed at an earlier stage than serous cancers.

Causes of primary peritoneal cancer

Primary peritoneal carcinoma is an idiopathic cancer that develops in the abdominal cavity's peritoneal layers. Its subtype, EOPPC, is similar to serous ovarian cancer and only develops in women (mean age, 56-62 years). There have only been a few accounts of it in males. Germline mutations in the BRCA 1 gene have been shown to cause it in 17.6% of cases. As a result, serous peritoneal cancer should be ruled out in any patient with familial breast cancer. Malignant peritoneal mesothelioma is an aggressive tumor that arises in older males and is caused by asbestos exposure in 33% to 50% of cases (60 years and older).

In postmenopausal women, disseminated peritoneal leiomyomatosis is linked with a high estrogenic state. Leiomyosarcoma, like retinoblastoma, is a secondary tumor in Li Fraumeni syndrome. Desmoplastic round small cell tumors are more common in teens (median age 19 years) and in Caucasians (85%).

Secondary peritoneal carcinomatosis is usually caused by infiltrating malignant cells from malignancies of

• The stomach, 
• Colon,
• Pancreas, 
• Gall bladder, 
• Appendix, 
• Breast, 
• Uterus, 
• Ovary, and 
• Lungs. 

The peritoneal involvement in appendiceal cancer is known as pseudomyxoma peritonei (PMP). It is effectively controlled and resulting in a lifetime free of recurrence. Metastasis from ovarian, gastric, and colorectal cancers is associated with an elevated risk of recurrence and death, and they are also the three most prevalent etiologies of metastatic dissemination in the peritoneum.

Symptoms of primary peritoneal cancer

Clinical presentation in peritoneal cancer is variable depending on the extent of involvement. It is usually diagnosed in late stages due to the vague symptomatology. Extraovarian primary peritoneal carcinoma (EOPPC) has an indistinguishable presentation from an epithelial ovarian cancer. The Gynecologic Oncology Group has defined the following criterion for primary peritoneal cancer diagnosis:

1. Both ovaries should be of normal size, and the enlargement is benign.
2. The surface area of malignant involvement of extra-ovarian sites should be larger than either of the ovaries.
3. There should be no malignancy in either ovaries or the tumor in serosa, and cortex of size less than 5X5 mm can be present.
4. The tumor in the extra-ovarian site should be serosal both histologically and cytologically. 

Non-specific symptoms of peritoneal cancer include abdominal bloating, distension, nausea, indigestion, anorexia, weight loss, weariness, constipation, and stomach or back discomfort. The most typical symptoms for presentation are abdominal distension and discomfort, with palpable abdominal mass and ascites as usual findings. In 85% of cases, patients experience nonspecific abdominal pains and ascites.

Tumor-associated lymphadenopathy produces localized swelling and can possibly result in superior vena cava blockage. This has mostly been observed in peritoneal malignant mesothelioma. In the absence of main involvement, mesothelium involvement is occasionally encountered as an accidental discovery in laparotomy or autopsy.

Peritoneal carcinomatosis has both primary tumor-specific symptoms and non-specific symptoms. The symptoms are determined by the level of involvement and location of secondary metastatic deposits, which can range from microscopic involvement to nodules to bulky disease.

Pressure effects caused by primary and subsequent tumor development result in mechanical intestinal blockage. These individuals report to the emergency room with an 'acute abdomen. In roughly 20% of instances, bowel blockages are observed in colorectal malignancies. Ascites were seen in 43% of pancreatic cancer patients in the same investigation.

Diagnosis of primary peritoneal cancer

PTC is often identified when a woman visits her doctor with abdominal edema and bloating. As previously stated, the symptoms of either cancer are often gastrointestinal rather than gynecologic in character. These symptoms are due to fluid collection, also known as ascites, which is frequent with either malignancy. Because tumor seedlings frequently border the peritoneal surface (the outer lining) of the intestines, a condition known as carcinomatosis occurs.

The omentum, a fatty tissue apron that hangs down from the colon and stomach, sometimes harbors bulky tumors known as omental caking. Although omental cakes can be found by a physical examination, they are often faint and difficult to identify. When a woman is discovered to have fluid in her abdomen (ascites), a CT scan is usually the first step toward a diagnosis. This is a sort of x-ray that allows doctors to examine the whole abdomen and pelvis.

Omental caking and ascites, as well as other tumor growths, are prevalent and suggest the presence of PPC, or ovarian cancer. Other malignancies can produce same results, thus more tests are required. These tests are mainly aimed at ruling out other more common diseases, such as colon and breast cancer.

Often, the examination of ascites begins with a paracentesis, in which fluid is extracted from the abdomen using a needle. Under a microscope, the fluid is analyzed for the presence of malignant cells. Unfortunately, the process of conducting a paracentesis can actually "seed" the abdominal wall with cancer cells, therefore this treatment is not without hazards.

When considering this operation, it is vital to get the counsel of a gynecologic oncologist since it may not be necessary given that the majority of patients with these abnormalities will undergo surgery regardless of the results. It may, however, be beneficial in patients who are not surgical candidates or who are suspected of developing ascites for causes other than cancer, such as liver or heart disease. Because of the patient's pain, fluid is sometimes taken off until surgery or chemotherapy can be planned.

When PPC is suspected, a number of blood tests are commonly conducted. The CA 125 blood test is the most prevalent. CA 125 is a substance produced by tumor cells that is commonly increased in people with PPC. Unfortunately, it can be increased in a range of benign illnesses as well as other tumors, therefore an elevated CA 125 blood test does not always indicate that the patient has cancer. Under recent years, a novel blood test has been developed that is less likely to be raised than CA 125 in benign situations.

The real diagnosis of PPC is frequently not clear until a lady has surgery. This is due to the clinical similarities between either condition and epithelial ovarian cancer. Under the microscope, PPC and ovarian cancer all look the same. The pattern of tumor spread and organ involvement in the abdominal cavity shows the underlying cancer's genesis.

Surgical staging

Cancer surgical staging is done to properly determine the degree of the illness. This enables decisions to be made about subsequent therapy, which is often chemotherapy. Surgical staging often entails removing all visible illness as well as the ovaries, fallopian tubes, and uterus. Depending on the surgical findings, it may also entail the removal of the omentum, lymph nodes, and other organs.

While there is no specific agreed-upon staging system for PPC, because it is so similar to ovarian cancer in terms of therapy, tumor status is often classified using ovarian cancer criteria.

The tumor's spread is described by the stages I through IV. Because warning signals are often sparse until the disease has advanced, nearly all patients diagnosed will be at Stage III or above. A pleural effusion is fluid that collects around the lungs in patients with PPC. If there is an effusion, some fluid may be taken to examine for tumor cells. If tumor cells are discovered in this fluid, the patient is diagnosed with Stage IV disease.

Treatment for primary peritoneal cancer

Surgery

The initial step in treating PPC is typically surgery, which should be performed by a gynecologic oncologist. The surgery's objective is to remove all visible illness because this method has been found to enhance survival. This is referred to as "debulking" surgery. The patient is regarded optimally debulked when all visible disease has been eliminated or if only tiny tumor implants (less than 1 cm in diameter) remain.

Occasionally, the position of the tumor within the abdomen or the patient's state prevents appropriate debulking surgery from being done. In this case, chemotherapy may be administered initially, followed by surgery at a later date. Most surgeries are conducted via a laparotomy, in which the surgeon creates a lengthy cut in the abdominal wall, however they are also regularly encountered during laparoscopy. If PPC is discovered, the gynecologic oncologist will carry out the following procedures:

• Salpingo-ooophorectomy: both ovaries and fallopian tubes are removed.
• Hysterectomy: the uterus is removed usually with the attached cervix.
• Omentectomy: the omentum, a fatty pad of tissue that covers the intestines, is removed.

Some of the adjacent lymph nodes may be removed on occasion. Depending on the surgical results, more extensive surgery such as small or large intestine resection and tumor removal from the liver, diaphragm, and pelvis may be undertaken. One of the most critical elements influencing cure rates is the removal of as much tumor as feasible.

Side Effects of Surgery

Following surgery, some soreness is normal. It is frequently treatable with medication. Inform your treatment staff if you are in pain. Other potential adverse effects include:

• Nausea and vomiting
• Infection, fever
• Wound problem
• Fullness due to fluid in the abdomen
• Shortness of breath due to fluid around the lungs
• Anemia
• Swelling caused by lymphedema, usually in the legs or arms
• Blood clots
• Difficulty urinating or constipation
• Talk with your doctor if you are concerned about any of the problems listed.

Chemotherapy

The employment of medications to destroy cancer cells is known as chemotherapy. It can be administered intravenously (injected into a vein) or, more recently, intraperitoneally, which has been linked to a longer life in patients with a very similar illness, ovarian cancer. Intraperitoneal chemotherapy includes the injection of medications directly into the abdomen via a catheter put under the skin during or shortly after the original operation.

Unfortunately, it has more acute adverse effects than intravenous chemotherapy, thus some patients prefer intravenous treatment. Intraperitoneal therapy is only administered once adequate debulking surgery has been completed. Either therapy can be given at the doctor's office, the hospital's outpatient treatment rooms, or as an inpatient.

Traditionally, intravenous chemotherapy is administered as an outpatient every three weeks. Each chemotherapy treatment is known as a cycle, and the initial treatment generally comprises of six cycles. Intraperitoneal chemotherapy is also administered every three weeks for six rounds. Each cycle is a little more complicated since the patient may receive treatments on several days of the 21-day cycle as opposed to only day 1 of the cycle if delivered intravenously.

The chemotherapy medications most typically used for PPC are the same as those used for ovarian cancer. Cisplatin or Carboplatin, as well as Taxane (Paclitaxel or Taxotere) in combination, are examples of platinum-based medications.

Side Effects of Chemotherapy

Chemotherapy affects everyone differently. Some people may have minimal side effects, while others may have many. The majority of adverse effects are quite transient. They are as follows:

• Nausea
• Loss of appetite
• Mouth sores
• Increased chance of infection
• Bleeding or bruising easily
• Vomiting
• Hair loss
• Fatigue
• Constipation
• Diarrhea

Follow-up after treatment

Following completion of first therapy, patients with either cancer are constantly monitored with visits every two to four months for the first three years, then every six months for another two years or so, and finally yearly. A physical exam, including a pelvic exam, CA 125 testing, and, depending on the patient and her condition, imaging tests such as CT scans, X-rays, MRIs, or PET scans are conducted at each appointment. These tumors likely to reoccur over time unless individuals are detected early. As a result, patients frequently require more than one round of chemotherapy, as well as extra surgical treatments.

Recurrent disease

Recurrences are prevalent in PPC patients because most individuals with either cancer are discovered at advanced stages of illness. The majority of patients will go into remission at first, but the illness will frequently return months to years later when CA 125 levels begin to increase or new masses are discovered on physical exam or imaging examinations. Unfortunately, if this cancer recurs, the prognosis is not positive, although a longer remission before recurrence is connected with a greater likelihood of a second, third, and even fourth remission.

Depending on the site of the recurrence, the duration since the original therapy, and the patient's general health state, there are numerous therapeutic choices for patients who recur. These alternatives include repeat surgery, re-treatment with the same chemotherapy as before, or a new drug. In some circumstances, radiation treatment may be recommended. Because each recurrence is unique, their therapy must be tailored to them depending on a variety of criteria, including those stated above. Unfortunately, if a recurrence is discovered, the aim of therapy must be re-focused to assist maintain quality of life rather than a cure.

Conclusion 

Primary peritoneal cancer (PPC) is an uncommon malignancy. It begins in the thin layer of tissue that lines the inside of the abdomen. The peritoneum is the name given to this tissue lining. Primary peritoneal cancer symptoms might be vague and difficult to detect. Many of the symptoms are more likely to be the result of another medical problem. The goal of surgery is to remove as much cancer from the abdomen as feasible before undergoing chemotherapy.