What Are the Stages of Bone Cancer (Bone Neoplasm)?

Cancer is one of the hardest diseases to correctly diagnose and treat. The first challenge for most oncologists is to locate the tumour and determine how far cancer cells have spread within the body. 

This is necessary so that the doctors can suggest a treatment method that would yield the best results. 

The Staging Process

The process of taking physical exams, biopsies and physical exams to determine the status of cancer in the body is called staging. In many cases, doctors are able to determine the stage of cancer during diagnosis itself. 

However, sometimes, further testing is required to correctly understand the extent of cancer growth in the patient’s body.  

Multiple staging systems are in place to help the doctors have a standard reference for cancer staging. These staging systems provide a rough framework in terms of symptoms, physical appearance, nature of the tumour and many other parameters. 

Once the team of doctors is able to gather the required data, it is easy to predict what stage the cancer is at. 

Bone Cancer Staging Systems

There are two main staging systems that are used to study and describe bone tumours before bone cancer treatment can begin.  

1. AJCC TNM Staging System

The American Joint Committee on Cancer – TNM staging system is based on four key data points: T stands for tumour size, N stands for spread to lymph nodes, M stands for metastasis to distant organs and G is the grade of the tumour. The job of staging and grouping can be done by any good cancer research institute.  

• T Stage– The T stage is broadly classified into 5 types: 
  • TX means that the primary tumour cannot be measured.  
  • T0 indicates that there is no evidence of the tumour.  
  • T1 means that the tumour is less than 8cm.  
  • T2 if the classification used for tumours that are larger than 8cm in size.
  • T3 is used for tumours that are in more than one place on the same bone.  
• N Stage– The N stage has two classifications: 
  • N0 is used for cancers that have not spread to the lymph nodes. 
  • N1 indicates that the cancer cells have spread to nearby lymph nodes.  
• M Stage– The four types under the M stage are used to describe the extent of metastasis to other organs: 
  • M0 shows that the cancer cells have not spread anywhere outside of the bone or nearby lymph nodes. 
  • M1 is the classification for distant metastasis.  
  • M1a indicates that the tumour has only spread to the lung.  
  • M1b means that the tumour has made its way to the other organs in the patient’s body. 
• G Stage– G1 and G2 are used for low-grade cancers, while G3 and G4 are used to describe high-grade cancers.  

2. MSTS Staging System

The Musculoskeletal Tumour Society staging system is also known as the Enneking System. This type of staging is widely used in most of the top cancer research institutes. 

It groups cancer tumours based on 3 data points: G stands for the grade of cancer, T is the extent of the primary tumour and M is the degree of metastasis. Similar to the TNM system, the MSTS system also tries to make it easier to identify and diagnose complex cancer tumours.  

• G or the grade of the cancer is essentially a measure of the appearance of cancer and its ability to grow. Any major abnormalities in the cells lead to the cancer being graded as G2 (high grade), while cells that appear normal to the eye under a microscope are graded as G1 (low grade). 
• The extent of the primary tumour, T can either be intra-compartmental or extra-compartmental based on whether or not the cells have spread outside the bone. Extra-compartmental cancers are those that have spread to nearby bone structures. 
• The degree of metastasis determines whether or not the tumour has spread to other organs. M0 indicates that it has not spread and M1 indicates that it has spread to nearby organs.  

Knowing the stage of cancer with utmost accuracy makes it easier for the doctor to suggest the right prognosis. With modern equipment and a strong team of experienced doctors, cancer can be fought in a smart and proactive manner. 

Early diagnosis and accurate staging are highly beneficial for the speedy recovery of a patient. Consult your doctor to further understand the care and treatment that would be required to support a complete recovery from bone cancer.