Tumor and Disease Staging

Excerpts from ESUN Articles

 

The tissue obtained from the biopsy is evaluated by a pathologist. The pathologist uses a number of diagnostic tools including light microscopy, immunohistochemistry, electron microscopy, and molecular studies to make the diagnosis. In addition to making a diagnosis, the pathologist also provides an important piece of information called the grade. The grade refers to a tumor’s appearance under the microscope and is a reflection of a tumor’s aggressiveness. High grade tumors behave more aggressively meaning they have a higher tendency to recur and spread. Low grade tumors are less aggressive and have a lower tendency to recur and spread. The grade is not a guarantee of a tumor’s behavior but rather is one of the factors that helps the treatment team make recommendations.

 

Once all of the imaging studies and biopsy have been performed, the stage of disease can be assigned. Patients often inquire about the stage of their disease. It must be kept in mind that stage is not a guarantee of a tumor’s behavior. Staging merely provides guidelines for the treatment team on how best to manage a given tumor to optimize clinical outcome.

A description of the staging for soft tissue sarcomas can be found in the article "How are Soft Tissue Sarcomas Staged?"

Carol D. Morris, MD, MS
V2N2 ESUN Copyright © 2005 Liddy Shriver Sarcoma Initiative.

Staging is important both in guiding treatment and in providing prognostic information. While many staging systems exist for soft tissue sarcoma, the most commonly used system is the AJCC system. This system classifies the tumor based upon histologic grade, the tumor size, location as superficial or deep, and the presence or absence of metastatic disease (see Table 1).

Table 1: AJCC staging system
Stage Histological
Grade		 Size Location
(Relative to fascia)		 Systemic / Metastatic
Disease Present
IA Low < 5cm Superficial or Deep No
IB Low ≥ 5cm Superficial No
IIA Low ≥ 5cm Deep No
IIB High < 5cm Superficial or Deep No
IIC High ≥ 5cm Superficial No
III High ≥ 5cm Deep No
IV Any Any Any Yes

The Surgical Staging System of the Musculoskeletal Tumor Society (MSTS) is also used. It is utilized for staging bone and soft tissue sarcomas. This staging system classifies tumors as Ia, Ib, IIa, IIb, or III based upon the histologic grade of the tumor, its local extent and the presence or absences of macroscopic distant metastatic disease. If the tumor is localized to a single anatomic compartment, it is said to be confined. If it has spread locally beyond its initial compartment, then it is said to be unconfined (see Table 2).

Table 2: MSTS Staging system
Stage Histological
Grade		 Local Extent of Disease Systemic / Metastatic
Disease Present
Ia Low Confined No
Ib Low Unconfined No
Ia High Confined No
Ib High Unconfined No
III Any Any Yes

 

The American Joint Committee on Cancer (AJCC) was established to formulate and publish systems of classification of cancer, including staging and end results reporting, which will be acceptable to and used by the medical profession for selecting the most effective treatment, determining prognosis, and continuing evaluation of cancer control measures. The Enneking system of surgical staging of bone and soft tissue tumors is based on grade (G), site (T), and metastasis (M) and uses histologic, radiologic, and clinical criteria. It is the most widely used staging system and has been adopted by the Musculoskeletal Tumor Society (see Musculoskeletal Tumors, Staging And Treatment Planning on the eMedicine website).

Michael J. Weaver, MD and John A. Abraham, MD
V4N2 ESUN Copyright © 2007 Liddy Shriver Sarcoma Initiative.