Mesothelioma Prognosis and Staging
The staging system for a disease are the assessment levels that the doctor uses to determine the amount and extent of tumour cells in the body. He bases his treatment decisions on the stage of disease. There are various staging systems used but the main one is the TNM system.
Staging of Mesothelioma
A staging system is not alway appropriate but the TNM staging system is sometimes used for peritoneal mesothelioma.
T refers Tumour size and extent
N refers to Nodes - has the tumour spread to local lymph nodes?
M refers to Metastasis - has the tumour spread to another part of the body?
Numbers are allocated to each category of the TNM system.
The staging system used for pleural mesothelioma is called the IMIG system (International Mesothelioma Interest Group). It is however still based on the TNM system described above.
In this type of disease the tumour description ranges from 0 to 4 where 1 may indicate the tumour is located to one side of the pleura and 4 indicates that the tumour has extended throughout the pleura into surrounding organs
e.g. the spine, paricardium, peritoneum.
The nodal description also have disticnt descriptiors ranging from Nx (unable to assess) to N3. The M section is more straighforward with M0 or M1 - not present or present.
It appears complicated but once all the relevant information has been gathered about the tumour, nodes and possible metastasis, the different categories are split into 4 simplified stages . . .
Stage 1 being the earliest ranging through to Stage 4 - the most advanced stage of the disease.
With a stage 4 pleural mesothelioma case, surgery cannot be used as the tumour has spread throughout the chest and entered the peritoneum or the lymph nodes or spread to other parts of the body.
The disease has a long latency period, 50 or 60 years in some cases and may not be diagnosed until the patient is in the advanced stages of the cancer. This means that the prognosis for Mesothelioma tends to be rather bleak, with patients only surviving a year or two after the diagnosis is made. There are several factors that determine the prognosis:
How old is the patient?
Generally, younger patients will be stronger and more able to cope with the treatment than older patients who may have other non related health problems e.g. high blood pressure.
How advanced is the cancer?
The symptoms may be similar to those for other diseases or conditions, so the Mesothelioma may be quite advanced before being properly diagnosed. This means it may have spread to other parts of the body and be more difficult to treat.
The type of Mesothelioma?
Pleural mesothelioma carries the best rate of survival. Peritoneal and pericardial mesothelioma are harder to treat.
The type of Histology?
The type of histology depends on the characteristics of the cell structures and affected tissue.
50 percent of patients have Epithelial Histology. 10 - 20 percent of patients have Sarcomatoid Histology. 30 - 40 percent have both types, known as Biphasic or mixed.
Patients with the Epithelial type of Mesothelioma usually have a better prognosis than the other types.
A rarer histological type of mesothelioma is Papillary Mesothelioma, which is found in women in their 30s and 40s and is Epithelial in nature.
A prognosis is very difficult for a consultant to predict accurately - it is an educated guess at best. Reasearch undertaken over the past decade has refined and developed mesothelioma treatments and as a result the survival rates are improving. There are many cases of patients with good prognostic indicators - younger, no other health complications, early stage operable tumour, epithelioid tumour - that are still alive several years following treatment.