To treat a cancer, it’s imperative that we need to know how far it has spread. Based on the degree of its spread in the organ concerned, its surrounding area and to other distant parts of the body, the cancer is staged. Each stage has a specific treatment method to achieve optimal results. Hence staging is a must before starting treatment.
The patient will be advised to undergo imaging investigations like CT scan, MRI scan or PET SCAN. These will help identify the spread of the disease.
Sometimes surgical procedures need to be carried out to rule out spread of small cancerous nodules to other parts as these small nodules may be missed by scans. E.g. Staging laparoscopy, thoracoscopy etc.
Human body is made of a variety of cells. E.g. nerve cells, liver cells, muscle cells. Cancer arranging in different cells behave differently and respond differently to treatments. Hence cancer of each organ is staged differently.
American Joint Committee on Cancer (AJCC)/ International Union Against Cancer (UICC) classify the anatomic staging of cancer based on the size of a tumor and any spread to nearby tissue (T); the spread of the cancer to nearby lymph nodes (N); and the spread of cancer to other parts of the body (M). This is commonly referred to as TNM staging.
This staging is universally used and accepted.
There are certain other staging systems for specific tumors.
The outcomes in the cancer treatment are measured in terms of cure rates, survival and recurrence of disease. Cancers in stage 1 and most stage 2 have a high chance of cure. But with increased stage the survival decreases and chance of recurrence increases. Cancer stage helps us in estimating the outcomes and optimize treatment to improve them.