Initial treatment for stage II colon cancer is surgery to remove the section of colon that contains the tumor and surrounding tissue with its blood vessels and lymph nodes.
A colectomy or colon resection is abdominal surgery to remove the section of colon where the tumor is located, tissue containing blood and lymph vessels surrounding the colon (mesentery), healthy tissue margins on either side and, if possible, at least 12 lymph nodes. Then the remaining ends of colon are reconnected with sutures or staples. This connection is called an anastomosis. There are two types of surgery:
- Open colectomy: An incision is made in the abdomen, surgery performed through the opening, and the incision closed with sutures and/or staples.
- Laparoscopic colectomy: Three small keyhole incisions are made in the abdomen to insert a lighted instrument and specially designed surgical instruments that can be manipulated within the abdomen. Sometimes an incision is made just long enough for the surgeon’s hand to assist during laparoscopy. This is also known as minimally invasive surgery.
The tumor, tissue on either side of it (the margins), and fat and lymph nodes attached to the colon are removed for further study by a pathologist. The pathologist evaluates the cancer cells in the tumor itself, looks for cancer in the margins and other tissue, and studies as many lymph nodes as possible in order to provide an accurate diagnosis.
If your lymph nodes are cancer free (also known as node negative), your diagnosis is stage II colon cancer.
Treatment of node-negative stage II colon cancer is controversial. While surgery to remove the tumor in the colon is universally accepted as initial treatment, the value of chemotherapy after that surgery to keep cancer from recurring (coming back) is hard for patients and doctors to judge.
It’s estimated that between four and five percent of patients with stage II colon cancer will benefit from chemotherapy. However, there are also side effects, some severe, associated with chemotherapy. A very few patients will die as a result of chemotherapy.
Because of the risks of treatment, researchers are looking for ways to identify patients who are at higher risk for recurrence, who are most likely to benefit from chemotherapy. Some factors have been identified that lead to higher risk for stage II patients including:
- T4 tumors that extend beyond the outer wall of the colon into adjacent tissues and organs
- Too few lymph nodes removed and examined (less than 12)
- Cancer cells in blood and lymph vessels surrounding the tumor (not the same as lymph nodes)
- Undifferentiated or poorly differentiated tumors
- Perforation (a hole) of the colon by the tumor
- A tumor that obstructs (closes off) the colon
It may help your decision to think about the problem in terms of numbers: In order to prevent 1 recurrence or death from all cases of stage II colon cancer 25 to 50 patients need to receive chemotherapy. One in six of those patients will have a severe side effect. 1 in 100 to 200 will die as a result of treatment.
For high-risk stage II patients, the number needed to prevent 1 recurrence or death is smaller, probably 15 to 30 patients.
Chemotherapy regimens for high-risk stage II colon cancer include
- FOLFOX: combination treatment with infusional 5-FU (fluorouracil), leucovorin, and oxaliplatin
- FLOX: combination with bolus 5-FU, leucovorin, and oxaliplatin (severe diarrhea is more common with FLOX than FOLFOX but outcomes are similar)
- Xeloda (capecitabine): oral “prodrug” which is converted to 5-FU in the tumor
- 5-FU and leucovorin
Your doctor can discuss the advantages and disadvantages of the different chemotherapy regimens if you decide to go ahead with chemotherapy after your surgery. Chemotherapy usually lasts about six months.
Another important option for treating stage II colon cancer is to enroll in a clinical trial.
C3 supports doctors discussing the risks and benefits of adjuvant chemotherapy treatment for stage II colon cancer with all patients so that patients can choose whether or not to go ahead with it.
Where Can You Go for More Information
The ASCO Patient Guide: Adjuvant Chemotherapy for Stage II Colon Cancer is available on Cancer.net and explains the research behind ASCO recommendations for chemotherapy after surgery for stage II colon cancer and its risks and benefits.
A comprehensive technical discussion of the existing clinical information about the stage II chemotherapy controversy can be found in the March 1, 2008 issue of Oncology. Led by Dr. Scott Kopetz from the M.D. Anderson Cancer Center at the University of Texas, Adjuvant Chemotherapy for Stage II Colon Cancer discusses data from clinical trials, toxicities, and recommendations from NCCN and ASCO.