M stage is the coding system used to record the absence or presence of distant metastases at the time of diagnosis of the primary cancer. It is part of the TNM cancer staging system.
Valid M codes from the current edition of the UICC TNM Classification of Malignant Tumours.
Refer to the UICC reference manual, TNM Classification of Malignant Tumours for coding rules.
Data element attributes
Collection and usage attributes
Guide for use:
Choose the lower (less advanced) M category when there is any uncertainty.
Collection methods:
From information provided by the treating doctor and recorded on the patient's medical record.
Comments:
Cancer prognosis and survival can be related to the extent of the disease at diagnosis. Survival rates are generally higher if the disease is localised to the organ of origin compared with cases in which the tumour has spread beyond the primary site.
Staging systems seek to classify patients having a similar prognosis into groups or stages. TNM staging is an internationally agreed staging classification system based on the anatomical site of the primary tumour and its extent of spread. The T component refers to the size of the tumour and whether or not it has spread to surrounding tissues. The N component describes the presence or absence of tumour in regional lymph nodes. The M component refers to the presence or absence of tumour at sites distant from the primary site.
TNM staging applies to solid tumours excluding brain tumours.
Source and reference attributes
Origin:
International Union Against Cancer (UICC)
Commission on Cancer, American College of Surgeons
Reference documents:
UICC TNM Classification of Malignant Tumours (5th Edition) (1997)
Commission on Cancer, Standards of the Commission on Cancer Registry Operations and Data Standards (ROADS) Volume II (1998).
