Laterality describes which side of a paired organ is the origin of the primary cancer. Each side of a paired organ is considered separately and described as lateral when occurring unless a physician determines that it is bilateral.
A paired organ is one in which there are two separate organs of the same kind, one on either side of the body (e.g. kidney, breast, ovary, testis and lung).
This information is collected for the purpose of differentiating the site of the primary cancer. For example, a woman may present with a primary cancer in the left breast. She may return at a later stage with a new primary cancer in the right breast.
Includes organs that are bilateral as a single primary (e.g. bilateral retinoblastoma (M9510/3, C69.2), (M9511/3, C69.2), (M9512/3, C69.2), (C69.6, C48.0), bilateral Wilms tumours (C64.9, M8960/3)) Note: Bilateral cancers are very rare.
It is unknown whether, for a paired organ the origin of the cancer was on the left or right side of the body.
This information should be obtained from the patient's pathology report, the patient's medical record, or the patient's medical practitioner/nursing staff.
Source and reference attributes
World Health Organization
Percy C, Van Holten V, Muir C (eds). International Classification of Diseases for Oncology, 2nd edition. Geneva: WHO, 1990