Colorectal Cancer (Rectal)

Cancer Monthly > Cancer Basics > Colorectal Cancer (Rectal)

The Cancer Monthly database currently has the results (survival, side effects, and more) for 45 recent colon cancer therapies and 50 recent rectal cancer therapies including biological therapy, immunotherapy, chemotherapy, radiation, and surgery.

Introduction

Colorectal CancerColorectal cancer means cancer of the large intestines. It may be in the colon (the large intestines) or the rectum (the lower 8 to 10 inches of the large intestines).

Colorectal cancer is the second leading cause of cancer death in adults. (The first is lung cancer.) In 2 004, there were 146,940 new cases of colorectal cancer and 56,730 deaths. This cancer appears to be related to a person’s diet such as consumption of calories, meat protein, and
dietary fat and oil.

Staging and Prognosis

The prognosis of colorectal cancer is related to the depth of tumor, penetration into the bowel wall, and whether the cancer has spread to lymph nodes or other organs. These variables are represented in various staging systems (e.g. Dukes, TNM and Numerical) which are nearly equivalent:

Dukes Stage TNM Stage Numerical Stage Pathologic Description Approximate 5-Year Survival Percentage
A T1 N0 M0 I Cancer limited to or just beneath the mucous membrane greater than 90%
B1 T2 N0 M0 II Cancer extends into muscular coat 85%
B2 T3 N0 M0 II Cancer extends into or through serosa 70-80%
C Tx N1 M0 III Cancer involves regional lymph nodes 35-65%
D Tx Nx M1 IV Distant metastases (i.e. liver, lung) 5%

For the TNM stage: T = depth of tumor presentation; N = whether cancer has spread to lymph nodes; M = whether there is distant metastases.

Treatment

Total removal of the tumor is considered the optimal treatment. In addition, a thorough physical exam should be performed before surgery to determine whether there is metastasis. This physical exam usually includes: chest x-ray, biochemical assessment of liver function, measurement of plasma CEA level, and colonoscopy of the entire bowel.

Radiation therapy, either before or after surgery, reduces the likelihood of pelvic recurrences but does not appear to prolong survival.

Chemotherapy in patients with advanced colorectal cancer is only of marginal benefit. The most popular drug is 5-fluorouracil (5-FU), but its use has only a 15-20% likelihood of reducing a tumor by about 50% for a limited period of time.

When there is liver metastasis, some treatments infuse chemotherapy directly into the hepatic artery. This type of treatment is toxic and does not appear to prolong survival.

Many treatments also combine folinic acid (also called leucovorin) with 5-FU. The administration of these two drugs for six months after resection of tumor in patients with stage C disease leads to a 40% decrease in recurrence rates and 30% improvement in survival. But, the effects on survival for other stages of disease appear to be marginal.

Treatment Results

Various immunological and biological treatments (i.e. farnesyl transferase inhibition, inhibition of the epidermal growth factor receptor and the vascular endothelial growth factor) are undergoing evaluation in advanced disease. The Cancer Monthly database currently has the results (survival, side effects, etc.) for 45 recent colon cancer therapies and 50 recent rectal cancer therapies including biological therapy, immunotherapy, chemotherapy, radiation, and surgery.

 

Source: Robert J. Mayer, Gastrointestinal Tract Cancer, in HARRISON’S PRINCIPLES OF INTERNAL MEDICINE, pt. 5 § 77, at 527-531 (Dennis L. Kasper, M.D. et al., eds, 16th ed 2005).