Liver cancer. Sectioned gross clinical specimen of malignant (cancerous) tumours (neoplasms) of the liver. This is an angiosarcoma, caused by the use of the chemical thorotrast for a contrast X-ray. From 1930 to 1950, a suspension of thorium dioxide (ThO2, also known as thoria or thorotrast) was injected into some patients to make soft tissue visible on X-rays. Thorotrast has now been shown to be carcinogenic (cancer causing). Treatment of this cancer involves anticancer drugs, which may allow the patient to survive longer, but ultimately only a transplant will effect a cure. A similar condition can occur in plastic factory workers, due to the absorption of vinyl chloride.