A.9 Cancer
Cancer is a disease that can occur in all types of body tissue. It is found in many
forms, including solid tissue formations (tumours or neoplasms), leukaemias
(blood cancer) and lymphomas (cancer of the lymphoid cells). Cancers are due
to a reduction in control or loss of control of the growth of cells. This leads to a
proliferation of cell growth. In its early stages the cells formed by this growth
resemble the parent but as the cancer progresses they lose the appearance and
function of the parent cell. This loss of function if left unchecked will become life
threatening. For example, a growing tumour will obstruct, block and generally
affect adjacent organs. If these are nerves it will cause pain. Furthermore, cancer
cells are invasive. As the cancer grows, the cells lose their adhesion and the
malignant cells are carried in the blood to other parts of the body. These cells
lodge in different parts of the body and grow into so called secondary cancers.
256 APPENDIX 9 CANCER