Peritoneal Mesothelioma Cancer
The cancer of the lining of the abdominal cavity is called peritoneal mesothelioma. It is not as common as pleural form; it comprises an estimated one fifth to one third of all diagnosed mesothelioma cases. This report of the Surveillance, Epidemiology and End Results (SEER) approximates the number as 54.7% male and 45.3% female, with the age ranging from 65 to 69. The period of latency is shorter for patients exposed in asbestos, the symptoms appearing after 20 to 30 years from exposure; the usual latency period for pleural mesothelioma is 30 to 40 years.
Peritoneal Mesothelioma Symptoms
At the time of presentation, symptoms of peritoneal mesothelioma includes abdominal mass, abdominal pain, enlarged abdominal girth, fluid in the abdomen (ascites), distention of the abdomen, weight loss, fever, anemia, fatigue and digestive disturbances. For a few months before a confirmed diagnosis, some patients even complain of symptoms that are non-specific. Incidentally, peritoneal mesothelioma is found in a percentage of cases once the patient has other health complaints such as hernia, gallbladder or pelvic mass.
Doctors who have experiences in this field have noted that typically, patients have these symptoms six months to two years prior to the diagnosis. Men often come to the doctor complaining of a bulge in the groin (hernia) or around the belly button (umbilical hernia). For women, the first sign of a problem often occurs after a pelvic test when a tumor mass have been discovered.
In later stages of peritoneal mesothelioma, among the symptoms are increased occurrences of blood clots and obstruction of the bowel. There is a noticeable increase on the platelet count for 50% of peritoneal patients but this may be caused by various disorders, so this is actually of little help in the diagnosis. Low albumin level and anemia can also be among the symptoms.
Peritoneal Mesothelioma Diagnosis
Peritoneal mesothelioma has two clinical types which can be differentiated with the help of CT findings, the "dry" type and the "wet". It is classified as "dry" when there are multiple tiny masses or one dominant localized mass and generally little or no ascites. The "wet" type has widespread small nodules, no dominant mass and a presence of ascites.
If fluid is found, the process of eliminating it is through paracentesis; however the analysis of this fluid has limited diagnostic significance. Normally, a definitive diagnosis may be obtained through tissue biopsy.
As there is currently no staging system for peritoneal mesothelioma, the most popular system for general cancer staging (TNM system) is used. TNM system has the following criteria: (T) status of the tumor, (N) lymph nodes and (M) metastases. Other general categories may also be helpful in order to determine the stage.
Category 1 - with a localized lesion that can entirely be removed (resected)
Category 2 - the disease is located inside the abdominal cavity on peritoneal or organ surfaces where there is a probability of removing as much tumor as possible (debulking)
Category 3 - the disease is located inside the abdominal cavity and invades organs such as liver or colon.
Category 4 - the disease extends outside of the abdominal cavity
Peritoneal Mesothelioma Treatment
In the past years, the effectiveness of surgery alone or intraperitoneal chemotherapy in the treatment of peritoneal mesothelioma were not proven, that is why multimodality treatment is becoming more popular. Debulking (cytoreductive) surgery is removing all or nearly all visible tumors and may be combined with IPHC (Intra-Peritoneal Hyperthermic Chemotherapy), intraperitoneal chemotherapy and radiation.
Removing all tumors is not always probable; the prognosis for survival can then be in accordance with the completeness of cytoreduction which is established by these criteria:
(CC-0): No peritoneal seeding is found within the operative areas
(CC-1): Nodules less than 2.5 cm carries on after cytoreduction which can be penetrated by intra-cavity chemotherapy; thus the process is termed complete.
(CC-2) Nodules with sizes of 2.5 to 5 cm carry on after cytoreduction
(CC-3) Nodules that are larger than 5 cm are found; or there is a merging of tumor nodules that are unresectable at any area within the pelvis or abdomen.
Some patients may have widespread disease where surgery is not considered as "potentially curative", palliative treatment may be done by debulking. Take note that specialized treatments should only be administered by seasoned doctors because peritoneal mesothelioma is a rare malignant disease.
Recently, a clinical trial discovered Alimta (pemetrexed) to be effective as chemotherapy agent on treating peritoneal mesothelioma, either on its own or combined with cisplatin or any platinum-based drug. This reflects the previous findings regarding pemetrexed medication of pleural mesothelioma.