Asbestosis, the nervous system and cancer

Asbestosis patients have a high cumulative risk of cancer: four of ten asbestosis patients develop cancer. Paraneoplastic involvement of the nervous system, peripheral neuropathy in particular, is often encountered in cancer patients, even at very early stages of the disease. In order to estimate the occurrence of paraneoplastic neuropathy among asbestosis patients, we formed a small cohort (115 asbestosis patients, mean age 56 years, mean duration of exposure to asbestos 21 years) in 1979. Neurological examination revealed slight peripheral neuropathy in 44 (39%) of the patients, 24 (22%) of whom also had central nervous system signs (disturbances in gait and posture, memory and fine movements). The prevalence of peripheral neuropathy among asbestosis patients was higher than among various referent patients (fibrosing alveolitis, diagnosed solvent poisoning and gynaecological carcinoma). No significant differences were found between the patients with and without peripheral neuropathy regarding the following parameters: pulmonary function tests, tumour markers (CEA, ferritin, beta-2-microglobulin), antinuclear antibodies, C3, C4 and circulating immune complexes. Nevertheless, at group level, the asbestosis patients had increased levels of the three tumour markers. Estimates based on the data accumulated so far (10 cancer patients) show that within three years we shall probably have a sufficient number of cancer cases to draw some conclusions about the value of neuropathy in the early diagnosis of occupational cancer.