What
is mesothelioma?Malignant mesothelioma, a rare cancer, is characterized
by malignant cells found in the pleura, the peritoneum or the pericardium. How
common is mesothelioma?Between 1973 and 1999, 5266 cases were recorded
in the USA. The incidence rate for mesothelioma was 0.97 per 100,000. This incidence
rate was age-adjusted to the 2000 U.S. standard. The incidence rates by sex showed
a much higher incidence for men than for women, with 1.8 versus 0.4 per 100,000.1 How is mesothelioma transmitted?Malignant
mesothelioma is primarily an industrial disease, aquired by inhaling asbestos
fibres. However, others have acquired the disease in the home - family members
inhaling fibres brought home on clothing, for example. Can
mesothelioma be spread from person-to-person?No. Who
is most at risk?People working with asbestos or materials contaminated
by asbestos. What are the symptoms of mesothelioma?Early
symptoms are often non-specific, which may lead to a delay in diagnosis. Mesothelioma
may resemble viral pneumonia, with shortness of breath, chest pain and/or persistent
cough. Occasional symptoms of pleural mesothelioma include fever, night
sweats and weight loss. Peritoneal mesothelioma may include pain or swelling in
the abdomen due to a build-up of fluid, nausea, weight loss, bowel obstruction,
anemia or swelling of the feet. How soon after contamination
will symptoms show?Mesothelioma has a latency period of up to 50 years,
35-40 years being common in construction workers. Periods of less than 20 years
have been reported. How is mesothelioma diagnosed?Clinical
and radiological findings may suggest the diagnosis, and a review of the medical
and occupational history is taken. A physical examination, x-rays of the
chest or abdomen, and lung function tests are routine; a CT scan or MRI may also
be requested. A biopsy or examination of exudate from the affected area
will be necessary to confirm this diagnosis. How is
the stage established?The standard staging system is the the TNM System,
used in most cancers; variables of T (tumor), N (lymph nodes), M (metastasis)
- Stage I: Right or left pleura involved; spread to the lung, pericardium,
or diaphragm on the same side is possible. Lymph nodes are not involved.
- Stage II: Mesothelioma has spread from the pleura on one side
to local lymph nodes near the lung on the same side. It may also have spread into
the lung, pericardium, or diaphragm on the same side.
- Stage
III: Mesothelioma is found in the chest wall, muscle, ribs, heart, oesophagus,
or other organs in the chest on the same side with or without spread to lymph
nodes on the same side as the primary tumor.
- Stage IV:
Mesothelioma has spread into the lymph nodes in the chest on the side opposite
the primary tumor, or extends to the pleura or lung on the opposite side, or directly
extends into organs in the abdominal cavity or neck. Any distant metastases is
included in this stage.
Is there a treatment
for mesothelioma?The long latency of the disease, often without any knowledge
of asbestos exposure, means that the disease may be quite advanced by the time
the diagnosis is confirmed. This can limit the options available; treatment
should be commenced as soon as possible, for best results. There are three
treatment options, Surgery, Chemotherapy and
Radiation Therapy. - Surgically,
tumors that can be visualized can be resected; this can include removal of a complete
lobe, even a complete lung. However, like many metastatic cancers, there are likely
to be traces of the disease that cannot be visualized, even with the latest equipment,
so surgery cannot be a complete solution.
- Chemotherapy is based
on platinum drug combinations, with varying success; chemotherapy can be a usful
therapy in early mesothelioma, and working in combination with surgery or radiotherapy.
- Radiotherapy has a role in shrinking tumours prior to surgery, also
after surgery and as a paliative measure for late symptom control. as with all
metastatic cancers, radiotherapy cannot provide a cure for mesothelioma, but can
be effective in some patients, when combined with other approaches.
What
is the prognosis for mesothelioma?Historically, mesothelioma has had an
appalling prognosis; but in recent years, with better and earlier diagnosis, this
has improved. Patients whose disease is caught early can expect effective treatment,
while many patients who cannot be offered curative therapy can hope for an extended
period of palliative care, with effective symptom control. What
is the mortality rate for mesothelioma?
During 1999-2005, a total of 18,068 malignant mesothelioma deaths were reported in the United States; 14,591 (80.8%) occurred among males and 17,180 (95.1%) among whites. Mortality increased with age, with the greatest number of decedents aged ≥75 years. 311 deaths (1.7%) occurred in persons aged ≤44 years.
During this time, the total number of malignant mesothelioma deaths increased 8.9%, from 2,482 in 1999 to 2,704 in 2005, but the annual death rate was stable (14.1 per million population in 1999 versus 14.0 in 2005). The death rate for males was 4.5 times that for females (23.2 versus 5.1 per million).
Is there a way to prevent infection?Avoidance
of contact. In practice, this means total body protection for asbestos workers,
and careful decontamination of items found to contain asbestos (eg buildings,
trains and aircraft, mostly 40+ years old). Can
mesothelioma be controlled environmentally?The dangers of asbestos were
not understood until the material had become widespread in building, particularly
for heat insulation. It's use has been discontinued in most countries, and is
removed and disposed of safely when discovered. There is a lot of it about. In
the UK, for example, the Asbestos Removal Contractors Association is a non-for-profit
trade association committed to "... working with enforcing authorities and
member companies to strive for continuous improvement in standards, quality, safety
and efficiency." Is there legal protection for
workers and others? Most countries recognize asbestos as a hazardous material,
and have lawsy to protect workers and others who may be at risk. Employers have
a duty of care to employees and to third parties who may not be aware of the dangers
faced on contaminated sites. There is legal precedent for compensation payments
to those involved, running into millions. But as the disease has such a poor prognosis,
prevention and avoidance is a better choice, where possible. If you think
you have been contaminated with asbestos, get both medical and legal advice -
but see the doctor before the lawyer. Bibliography
and Further Information Sources
References
- CDC: Mesothelioma
mortality
I regret I cannot assist with individual cases or essays and school projects,
but if it's something I've missed, I'll be happy to try and help.
Article written by Andrew Heenan BA (Hons), RGN, RMN
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