Tumor Staging and Treatment
Tumor staging is used by investigators and clinicians to group patients who have tumors with like characteristics into subgroups. Generally, grouping is according to
- Tumor size
- Extent of disease to the lymph nodes
- Evidence of spread to distant organs-metastasis
There are many different staging systems; however, the system most commonly used in describing CRC is the Tumor, Nodes, Metastasis (TNM) system of the American Joint Committee on Cancer (AJCC).1 Table 1 shows the AJCC TNM sustem compared with another commonly used staging system developed in 1932 and subsequently modified, the Dukes' classification system.2
Table 1. American Joint Commission on Cancer (AJCC) Staging for Colorectal Cancer: Tumor (T), Node (N), Metastases (M)
|
Classification |
Description |
|
TX |
Primary tumor cannot be assessed |
|
T0 |
No evidence of primary tumor |
|
Tis |
Carcinoma in situ |
|
T1 |
Tumor invades submucosa |
|
T2 |
Tumor invades muscularis propria |
|
T3 |
Tumor invades through the muscularis propria into the subserosa or into nonperitonealized pericolic or perirectal tissues |
|
T4 |
Tumor perforates the visceral peritoneum or directly invades other organs or structures |
|
NX |
Regional lymph nodes cannot be assessed |
|
N0 |
No regional lymph mode metastases |
|
N1 |
Metastasis in 1-3 pericolic or perirectal lymph nodes |
|
N2 |
Metastases in > 4 pericolic or perirectal lymph nodes |
|
MX |
Presence of distant metastasis cannot be assessed |
|
M0 |
No distant metastasis |
|
M1 |
Distant metastasis |
|
Stage |
Primary Tumor (T) |
Regional Lymph Nodes (N) |
Distant Metastases (M) |
Dukes |
|
0 |
Tis |
N0 |
M0 |
— |
|
I |
T1 |
N0 |
M0 |
A |
|
|
T2 |
N0 |
M0 |
B1 |
|
IIA |
T3 |
N0 |
M0 |
B2 |
|
IIB |
T4 |
N1 |
M0 |
B3 |
|
IIIA |
T1-T2 |
N1 |
M0 |
C1 |
|
IIIB |
T3-T4 |
N1 |
M0 |
C2/C3 |
|
IIIC |
Any T |
N2 |
M0 |
C1/C2/C3 |
|
IV |
Any T |
Any N |
M1 |
D |
*From American Joint Committee on Cancer,1 with permission.
CRC Treatment
Clinical trials testing the efficacy and safety of new agents, combinations of drugs, and multimodal therapies analyze study findings according to subgroups of patients with CRC, because there are differences in response, depending on extent of disease and various host factors. This approach helps physicians to base their recommendations on scientific evidence and to customize their treatment recommendations to the individual, thus ensuring that the patient will receive the best evidence-based therapy available given his or her particular clinical situation. National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines for Oncology® are evidence-based recommendations for the treatment of colon3 and rectal cancers.4
References
- American Joint Committee on Cancer. AJCC Cancer Staging Manual, 6th ed. New York: Springer-Verlag; 2002.
- Dukes CE. The classification of cancer of the rectum. J Pathological Bacteriol. 1932; 35:323
- National Comprehensive Cancer Network. Practice guidelines in oncology: colon cancer, v2.2009. Retrieved August 7, 2009 from
http://www.nccn.org/professionals/physician_gls/PDF/colon.pdf
- National Comprehensive Cancer Network. Practice guidelines in oncology: Rectal Cancer, v2.2009. Retrieved August 7, 2009 from
http://www.nccn.org/professionals/physician_gls/PDF/rectal.pdf