For healthcare professionals

Asbestosis is a diffuse interstitial pulmonary fibrosis, barely distinguishable from idiopathic pulmonary fibrosis, but with a slower clinical and functional progression. This disease manifests as shortness of breath on exertion or even at rest, with few exacerbations, unlike idiopathic pulmonary fibrosis.

Pulmonary function tests show a reduction in total lung capacity and/or diffusion capacity. Asbestos does not cause chronic obstructive bronchopathy. In minimal forms of asbestosis, pulmonary function abnormalities may sometimes be absent.

On high-resolution chest CT scans, we observe more than just a diffuse infiltrative pathology, mainly in the posterior and lower regions, in the form of traction bronchiectasis or “honeycombing.”

If the clinical course, imaging, and pulmonary function tests are consistent with asbestosis and do not point to another diagnosis, proof of at least 25 fiber-years of exposure must still be provided.

Asbestosis occurs only in people who have had heavy asbestos exposure, always of occupational origin. Such exposures have practically disappeared in Belgium since the mid-1980s, when strict exposure limits were introduced to protect workers. The effect of these regulations has been a steady decrease in new cases of asbestosis, which were also significantly less severe. In recent years, the recording of new cases has become exceptional.

Asbestosis is (or was) a typically occupational disease in our country. No cases of asbestosis resulting from environmental exposure are known.

Diffuse pleural thickening corresponds to fibrosis of the visceral pleura and is not specific to asbestos exposure, especially if it is unilateral. It can also result from an infection or a hemothorax, for example. Diffuse pleural thickening is visible on a chest CT scan. It is frequently associated with abnormalities in the adjacent lung tissue, such as rounded atelectasis and “crow’s foot” patterns. Diffuse pleural thickening, particularly extensive rounded atelectasis, can cause a moderate restrictive impairment of respiratory function, which may be sufficient to qualify for compensation.

For completeness, pleural plaques should also be mentioned here: these are thickenings and calcifications of the parietal pleura, commonly found in people exposed to asbestos, but they rarely cause symptoms. Individuals with pleural plaques are not more predisposed to developing other asbestos-related diseases than people without plaques who had the same asbestos exposure.

Pleural plaques are often discovered incidentally during radiological examinations performed, for example, due to symptoms from another lung condition. This condition does not qualify for compensation from the Asbestos Fund, nor through occupational disease insurance: it is not listed among the compensable conditions under the Asbestos Fund, and it does not cause compensable damage under occupational disease insurance.

Mesothelioma is a primary malignant tumor—epithelial, sarcomatoid, or mixed—of the pleura, peritoneum, or pericardium. Diagnosis relies mainly on histology and immunohistochemical techniques. Given the complexity of this diagnosis, Fedris always requests a review of the pathological material by the Mesothelioma Commission—a panel of nine pathologists (mainly from academic hospitals) that meets monthly. For this reason, the pathological material is always required.

When a histological diagnosis is lacking, the diagnosis can exceptionally be accepted based on cytological examination of pleural fluid or on a suggestive radiological image combined with a compatible clinical course. An autopsy can sometimes be useful; however, Fedris will not request this examination on its own initiative.

In industrialized countries, a clear—usually occupational—exposure to asbestos can be demonstrated in about 80% of mesothelioma cases. The long latency period (up to 40 years or more) between initial exposure and disease onset is characteristic.

However, a minimum period of ten years is required to attribute the condition to asbestos exposure. Other well-documented but much rarer causes include: other mineral fibers (including erionite), high doses of ionizing radiation, and chronic serosal inflammation. The incidence of mesothelioma is increased in families with a BAP1 gene mutation. Nevertheless, in some cases of mesothelioma, no cause or risk factor can be identified.

Mesothelioma is also regularly observed in people exposed to asbestos not through their occupation, but through domestic exposure. Cases have been reported in wives of workers who brought home asbestos dust on their work clothes. Other cases occurred among people living near asbestos-processing factories, or among DIY enthusiasts who used asbestos-containing materials in their homes. Due to the long latency between asbestos exposure and disease onset, such cases may still appear today.

Lung cancer (bronchial carcinoma) is far more common in the general population than mesothelioma, but the link to asbestos exposure is much weaker. The increased risk of lung cancer is estimated at 0.5–4% per fiber-year.

If we apply the upper limit of this range (the worst-case scenario), a cumulative exposure of 25 fiber-years is considered to double the risk of lung cancer (Asbestos, asbestosis, and cancer: the Helsinki criteria for diagnosis and attribution. Scand J Work Environ Health 1997;23:311–6). This is therefore very likely an overestimation of the actual risk.

The risk increase from smoking and asbestos is multiplicative: if asbestos increases the risk by a factor of 2 and cigarette consumption increases it by a factor of 20, the combined relative risk from both exposures would be 40. Although cigarette smoking contributes far more to lung cancer risk than asbestos exposure, smokers are treated the same as non-smokers under the Asbestos Fund and occupational disease insurance.

There are no clinical, radiological, or histological features that allow differentiation between lung cancer caused by asbestos and other lung cancers. However, the diagnosis must be certain, which generally requires pathological evidence.

As with asbestosis, a cumulative asbestos exposure of at least 25 fiber-years is required. In practice, this mostly refers to exposures that occurred under working conditions before the mid-1980s.

The statistical link between asbestos exposure and the development of laryngeal cancer is weaker than for lung cancer. Other known risk factors, which are more significant than asbestos exposure, include smoking and alcohol consumption. However, laryngeal cancer may be considered for compensation if the patient can prove at least 25 fiber-years of asbestos exposure, regardless of exposure to other risk factors.

Laryngeal cancer causes symptoms at an early stage: persistent hoarseness, changes in the voice, the sensation of a lump in the throat, sore throat, and coughing. This condition can be detected through a laryngoscopic examination. Confirmation of the diagnosis requires pathological examination of a biopsy sample.

Asbestos-related ovarian cancer is a relatively rare condition: there are around 700 cases per year in Belgium, with the average age at diagnosis being 65. The incidence of ovarian cancer in Belgium has been gradually decreasing over the past twenty years.

Most ovarian cancers are epithelial tumors (adenocarcinomas).

Ovarian cancer is often asymptomatic in the early stages. Symptoms appear later but may be non-specific, such as loss of appetite and weight loss.

Ovarian cancer is generally treated with surgery and chemotherapy. The causal relationship between asbestos exposure and the development of ovarian cancer appears to be well established in the medical-scientific literature.

In Belgium, this primarily concerns women who worked in the 1970s in factories producing asbestos-based ropes and textiles (e.g., fireproof clothing).

Indeed, the risk for this type of cancer is confirmed only for highly exposed groups; in epidemiological literature, the concept of significant exposure is mainly based on duration. A minimum exposure period — to be considered significant — can be estimated at 10 years (full-time). A list of working conditions and professions involving significant asbestos exposure has been established and is included in the Fedris criteria for asbestos-related ovarian cancer.

The presence of asbestos fibers in tumor tissue is not used as a criterion for recognizing ovarian cancer as an occupational disease.

For all asbestos-related diseases, it has been proven that incidence increases with cumulative asbestos exposure. In an individual case, however, it is difficult to prove that the disease was actually caused by asbestos. This proof is not required by the Asbestos Fund. The claimant only needs to demonstrate sufficient exposure to the risk of asbestos in Belgium. Except in the case of mesothelioma, the criteria are set by royal decree.

Cumulative asbestos exposure is determined by the concentration of asbestos fibers in the air inhaled and by the duration of exposure. Based on these data, a cumulative dose is calculated and expressed in “fiber-years.”

To be eligible for compensation for asbestosis, lung cancer, laryngeal cancer, or ovarian cancer, the royal decree requires a cumulative asbestos exposure of at least 25 fiber-years. According to current standards, this represents very high exposure: approximately 10 years of full-time work in an environment with a high concentration of asbestos fibers in the air.

One fiber-year equals the total exposure over one year (1,920 working hours) for a person in a professional environment where the air concentration of asbestos fibers is one fiber per cubic centimeter. Exposure during a specific professional activity is calculated based on the average airborne asbestos concentration at the workplace and the actual duration of exposure.

This fiber concentration is determined using a list of activities with concentrations specified for each activity. If only certain activities or processes involved asbestos exposure, only the time spent on those activities or processes is considered.

For example, a person who worked 240 days per year, 4 hours per day, for 10 years sanding corrugated sheets containing asbestos would, according to the calculation method imposed by the royal decree, have been exposed as follows:

• Activity and fiber concentration: sanding corrugated sheets, 5 fibers/cm³

• Duration: 4 h/day × 240 days/year × 10 years = 9,600 working hours = 5 years

• Exposure: 5 fibers/cm³ × 5 years = 25 fiber-years

Cumulative exposures (duration × concentration) of 25 fiber-years were not uncommon in professional settings in the past (before 1985) but normally no longer occur in Belgium today.

For mesothelioma, the exposure requirements are much lower because even limited exposure significantly increases the risk. However, this exposure must also be proven.

When informing a patient of a diagnosis that may make them eligible for assistance from the Asbestos Fund, you can offer to submit a compensation claim directly on their behalf. If the patient first wants more information about the benefits they may receive, you can— with their consent—forward their contact details to the Asbestos Fund (use the form “Communicate the patient’s contact details to the Asbestos Fund”). If the patient does not wish to take immediate action, you can simply provide them with the brochure “The Asbestos Fund – What are my rights?”

WHAT DOCUMENTS SHOULD YOU ATTACH?
If the patient wishes to submit a claim, they will ask you to complete the medical certificate. In that case, attach at least the following documents:

For asbestosis or bilateral diffuse pleural thickening, attach:

• Pulmonologist’s report

• Chest CT scan (protocol and images or internet link)

• Pulmonary function tests (tracings and protocol)

• If available:

  • Mineralogical analysis of bronchoalveolar lavage fluid or lung tissue

  • Pathology report

For mesothelioma, lung, laryngeal, or ovarian cancer, attach:

• Specialist’s report

• Pathology report

• And, if available for mesothelioma:

  • CT scan (protocol and images or internet link)

  • Tissue sections, tissue block

For lung cancer specifically:

• CT scan (protocol and images or internet link)

• Mineralogical analysis of bronchoalveolar lavage fluid or lung tissue