Surgery is the primary treatment, resulting in the cure of about 50 percent of patients. Adjuvant chemotherapy (for colorectal cancers) and radiation therapy (for rectal cancers) probably increases survival. Most researchers now believe that adjuvant radiotherapy decreases local rectal recurrence without any improvement in survival. Combined radiotherapy and chemotherapy increases disease-free survival for rectal cancer more than radiotherapy alone and probably long-term survival as well. It should be recommended for people with high-risk tumors who are not candidates for participation in clinical trials .
The prognosis depends on how far the tumor has penetrated through the bowel wall or to adjacent structures and on whether the cancer has spread to local lymph nodes . In node-negative patients, local recurrence is about 5 to 10 percent for Stage I and 25 to 30 percent for Stage II.
Recent studies indicate that the number of local lymph nodes involved is important. When one to four nodes are involved, survival is significantly better than when more than four nodes are involved.
Poor prognostic factors for both colon and rectal cancer include:
• The tumor has penetrated the bowel wall.
• The tumor has perforated the bowel wall.
There are several features of rectal cancer that suggest an unfavorable outcome:
• The tumor is fixed, has invaded or adheres to other parts of the pelvis or adjacent tissues.
