Heart cancer. Gross clinical specimen of a heart showing numerous cancerous growths (lumps) on the pericardium, the outer lining of the heart. These are secondary tumours. The original (primary) tumour was in the lungs (not seen). When tumours spread from one site to another in the body, it is called metastasis. Surgical removal of all the affected areas, followed by chemotherapy and/or radiotherapy, may effect a temporary cure, but after metastasis the prognosis is poor. Lung cancer is nearly always caused by cigarette smoking.