Though we have looked in detail about mesothelioma in general and the treatment of mesothelioma in particular, we have not discussed at length about the Peritoneal Mesothelioma. Let’s start.

Peritoneal mesothelioma is a very rare cancer. It is also less prevalent as compared to pleural mesothelioma. It occurs in 30% of all mesothelioma cases. The annual incidence varies from 300 to 500 in US. After asbestos exposure, the latency period that elapses until occurrence of symptoms is 20 to 30 years, which is less as compared to pleural mesothelioma. It is believed to be an aggressive form of mesothelioma in all varieties. Though aggressive, it is postulated that the mortality rate is lesser as compared to pleural variety, that is, death is prolonged.

What happens in this malignant mesothelioma?

Peritoneum is a lining that sheaths the abdominal organs. The cells in this lining secrete a fluid that helps the organs to move against each other without friction as while passage of food through intestines. It is made up of two parts, visceral layer and parietal layer. The visceral layer sheaths the internal organs and parietal layer covers the abdominal cavity. The cancer causes these cells to overproduce the fluid. This leads to an excess fluid in the abdominal cavity.

What are the probable causes?

Though the well-known asbestos exposure is the prime cause of concern, it is also stated that, the peritoneal mesothelioma is usually a metastatic variety of pleural cancer. It is usually the result of spread of cancer from lungs to abdomen. It is propounded that the asbestos fibers may be inhaled and then through the draining lymph nodes, it may be disseminated to the abdomen. It is also possible that the asbestos fibers are ingested and resulted in peritoneal cancer.

What are the presenting symptoms of peritoneal mesothelioma?

1) It is observed that these patients usually present with large volume of Ascites, that’s increase in the girth of abdomen because of fluid accumulation.

2) There may be abdominal pain or a palpable mass.

3) There can be constitutional symptoms like fever, weight loss, nausea, anemia or digestive disturbances, etc. associated with the cancer.

4) Many a times, the diagnosis of peritoneal mesothelioma is an accidental finding. The patient usually presents with some other symptom like pelvic pain, gall bladder pain, hernia or just plain gastric disturbance.

5) Some patients complain of vague, non-specific symptoms for a number of months prior to diagnosis of cancer is done.

How to diagnose the condition?

There are two types of malignant mesothelioma affecting abdominal peritoneum.

1) Dry- in this type, CT scan reveals multiple small masses or a single dominant mass that is localized. Ascites is usually very minimal or even absent.

2) Wet- in this type, CT scan may reveal scattered small nodules but there is never a single localized mass. Ascites is usually present.

If the fluid is in excess, it may be removed by a procedure called paracentesis. But the fluid analysis cannot be considered as definitive for the diagnosis of malignant mesothelioma.

The definite diagnosis can only be obtained by biopsy of the tissue done during laparoscopic exploratory.

Staging and Treatment of the peritoneal mesothelioma

Today, no exact staging technique is available for peritoneal mesothelioma. For the treatment purpose, staging is done as per the norms of staging of any cancer. It is called TNM staging (T- tumor, N-lymph nodes, M- metastasis). So, the first stage is a completely localized cancer that can be controlled wholly. The second stage includes a cancer in the abdominal cavity, on the organ surfaces. Here cytoreduction also called as debulking is carried out in which surgeons remove as much visible tumor as possible though not all.

For many patients, surgeons and physicians opt for a multi-modal therapy as a single therapy like surgery has proven ineffective. Usually depending on physician’s consultation, the surgeons combine the cytoreductive surgery with IPHC (Intra-peritoneal hyperthermic chemotherapy) and /or radiation. Also, depending on the response of the patient, systemic chemotherapy with pemetrexed and cisplatin is performed. But the earlier combination of debulking and IPHC has propagated the malignant cancer treatment in a better direction.

“Patience is not a virtue for mesothelioma patients, they need answers and help right now!” says Roger G. Worthington, a lawyer who has recently donated $2,00,000 to MARF (Mesothelioma Applied Research Foundation), an American non-profit organization, whose mission is to eradicate the dreaded cancer.

Considering it as an occupational hazard, US Occupational Safety and Health Administration (OSHA) has set limits for the acceptable levels of asbestos exposure (considered to be responsible for the cancer) in the workplace. It qualifies for the Industrial Injury benefit in Britain. Let’s see what are the various aspects of this life threatening pathology.

What is mesothelioma?

Mesothelial cells are the special cells that line the chest, abdominal and heart cavity. The tissues formed by these cells are called as mesothelium. These tissues produce a special lubricating fluid that allows the organs to move around. Mesothelioma is an uncommon but a potentially life threatening tumor arising from this mesothelial lining of serous cavities.

It is most often seen in pleural cavity and rarely in peritoneal cavity or pericardial sac (Greek- meso+thelioma, tumor of middle lining tissue). It is a highly malignant tumor associated with high mortality. In this disease, the cells of the mesothelium become abnormal and divide without control. They may invade nearby tissues and organs. The cancer cells can metastasize (spread) to other parts of the body.

Epidemiology

Though the statistics show an increasing trend to the dreaded disease, it is relatively a rare cancer. Men are affected more than women and the risk increases with the age. Almost 3000 patients are diagnosed with the disease each year in US alone.

It is a frightening fact that the developing world is using the asbestos, considered to be mainly responsible for the cancer, in exactly the same way as US did. The death tolls are expected to rise to 1 million over the next 30 years.

What causes the dreaded disease?

In general, a cancer begins with a genetic mutation. This mutation turns normal, healthy cells into abnormal cells. The accumulating growth of abnormal cells forms a tumor. The causes accountable for the initial genetic mutation are still being researched but many risk factors have been identified. It is always an interaction of various factors such as inherited tendencies, environment you live in, your health conditions and the lifestyle you choose.

Who are at risk?

In 70 to 80% of cases, the asbestos plays a role in the development of the disease. So, it is considered to be an occupational hazard. Asbestos is mined and used in many industries since 1800. During World War II, its use increased. The people working in asbestos mill, shipyard workers, workers in construction and heating industries are mainly at risk. It is also used for insulation, cement, brakes, flooring, roof shingles, etc. Asbestos is a group of minerals. They are the masses of strong flexible fibers that can be divided into thin threads and woven.

During manufacturing process, the tiny asbestos particles float in the air and may be inhaled or swallowed. The fibers may settle in the lungs or in the stomach, where they can cause irritation and the cancer develops, though the exact mechanism is not known. It can take 20 to 40 years or more, before the symptoms become apparent after asbestos exposure.

Also, people living in the houses of asbestos workers are at risk, as the workers may carry asbestos dust on their clothes, hair, etc. Smoking does not appear to increase the risk but a combination of smoking and asbestos exposure significantly raises the chances of air passage cancers.

Are there any other factors besides asbestos?

1) Minerals like asbestos- Zeolite, a naturally occurring asbestos like mineral is supposed to cause mesothelioma. It is used in countries like Turkey to construct homes.

2) Family history- as with some other cancers, family history is postulated to increase the risk of mesothelioma. But more research is needed to determine its true role.

3) Radiation- some researchers link thorium dioxide to the cancer. It is a radioactive substance used along with the X-rays for the diagnosis of different health conditions. But it is no longer used.

4) Virus – SV40 is a virus found in monkeys. This virus got in contact with human beings when the monkey cells were used for polio vaccine. It is also stated that this virus can have human-to-human transmission but it is not clear how.

What are the alarming findings of mesothelioma that need to be shown to physician?

(Signs and symptoms of the cancer)

They depend on the origin of cancer.

1) If the pleura are involved, the presenting symptoms usually are shortness of breath and chest pain while breathing. Sometimes unusual lumps of tissue can be felt under the chest cage. There can be unexplained cachexia (weight loss) and non-productive cough.

2) Peritoneal mesothelioma may present with abdominal pain, swelling, change in the bowel habit (unusual constipation or diarrhea), lump felt in the abdomen, etc.

3) If the cancer has spread to other parts of the body, there may be pain in the affected area, swelling of face and neck region with difficulty in swallowing.

Whatever your signs and symptoms indicate, remember that only a doctor can make a diagnosis of mesothelioma.

Screening and Diagnosis

Along with clinical examination depending on patients’ signs and symptoms, a doctor will carry out certain investigations for an exact diagnosis of mesothelioma. X-ray is often helpful for pleural cancers. CT scan or MRI is frequently used for more detailed assessment. But the surest possible diagnosis can be made only with a biopsy. It is a surgical procedure in which a small portion of mesothelium is removed and sent for laboratory investigation.

Depending on the area of affection, a doctor may perform a fine needle aspiration, thoracoscopy, thoracotomy, laparoscopy or laparotomy. Once the doctor examines the tissue under microscope, he can diagnose with certainty. He also comes to know the types of cells involved so that he can decide the staging of the disease and the treatment plan.

Staging – Usually four stages are considered.

1) The first stage includes a localized cancer, limited to a small area of chest or abdomen. Here surgery is a reliable treatment option.

2) Second stage includes an advanced cancer that has spread to the adjoining tissues like the lungs or the diaphragm.

3) Third stage is similar to second stage with an extra spread to the lymph nodes draining the affected area.

4) Fourth stage includes metastasis to the distant organs and tissues, like brain or lung tissues away from the cancer site.

Treatment of mesothelioma

After all the investigations and staging, now comes the right treatment. Unfortunately many a times, the cancer diagnosis is done in an advanced stage, making surgical options bleak.

Despite all the advances, definitive success in treating this cancer has still eluded the doctors. Mortality rates are still high, within a margin of 4 to 14 months.

Some people want to do everything possible opting for a small chance of cure and they are ready to bear certain side effects of the therapy. Some people are not ready to spend a fortune and ask the doctors to treat them in a manner that will have a hassle free death possible. They want their end days to be restful. Anyhow, it is good to discuss your treatment goals with your doctor.

The options include surgery, chemotherapy, radiation and clinical trials.

1) Surgery may be done in the initial stages to remove the affected tissue (pleurectomy or peritonectomy). Also it can be done to decrease the fluid in the chest to relieve the patient of breathlessness.

2) Chemotherapy- certain chemicals are used to kill rapidly growing cancer cells. Though there are side effects like hair loss along with chemotherapy, this is effective in slowing the growth of mesothelium. This causes much reduction in the signs and symptoms.

3) Radiation – Doctors aim at ‘whole chest radiation’ to have a larger area covered. But since there are other important organs like heart, lungs, spinal cord etc, they have to use low doses of radiation to spare these organs.

4) Multimodal therapy- All the treatment options are combined to have a better effect.

5) Along with these all, many clinical trials are being carried out on the patients with the hope to secure some commendable success.

How to cope with the situation?

Any cancer diagnosis can be devastating for the patient as well as his or her relatives. But taking control over the remaining time is the skill. After recurrent tests, investigations and treatment rounds for mesothelioma, decide how you want to spend your time and with whom you want to spend. Consult the societies like National Cancer Institute or American Cancer Society for more information.

Detailed information will make you more confident. There are toll-free phone lines of NCI that provide valuable information. Call NCI at 800-422-6237 or ACS at 800-227-2345. Try to surround yourself with a support network like friends and family. Their reassurance will have a high value. Do not hesitate to ask for help. Accept that you need it.

Prevention of the problem

Obviously extreme measures are taken to prevent such a dangerous cancer. Protection from asbestos is by far the most important prevention strategy. It is said that 90% of deaths are preventable by wearing a good-fitting facemask while working. It is mandatory that an asbestos worker needs to have a shower and change clothes before taking a lunch break or going home. Breaking up asbestos from older buildings is most dangerous. This causes the fibers to become airborne and you may inhale while breathing.

So, don’t try to remove asbestos from your home before hiring a qualified expert. Ask the expert to check your home for any asbestos that can be hazardous to your health. Take a few cursory precautions and you will be spared of the dreaded cancer!