Colon Cancer: An Oncology Perspective
Francisco A. Garcia-Moreno, M.D.
Colon cancer is best approached as a team and is readily preventable. Since any polyp located in the colon can develop into a malignancy, screening with a colonoscopy is of the utmost importance. Early removal of a polyp and/or early detection of a malignancy results in the increased chance of being cured.
The American Cancer Society has guidelines that clearly state when and at what intervals the population should be screened. The patient's primary physician should implement these guidelines. The physician’s expertise and experience will help to adapt these guidelines to the individual patient.
At the present time, it is in the hands of a surgeon to cure this disease. Surgical removal of malignant lesions is the only known way of curing this disease. In certain settings (i.e., rectal cancer) a radiation oncologist will contribute to this curative effort.
If it is not possible to have a surgical cure to colon cancer, medical oncologists may contribute in any of three ways:
The first way is in conjunction with the surgical treatment. When the medical therapy is administered prior to surgery, we say that it is neoadjuvant therapy . With this type of therapy, we seek to shrink the size of a patient's lesion thereby helping the surgeon's ability of removing the tumor completely. If the medical therapy is administered after surgery, we are utilizing adjuvant therapy in an effort to eradicate metastatic cells and by doing so, decrease the risk of the patient developing recurrent disease.
The second way is using chemotherapy in treating the disease. If the patient clearly has metastatic disease, the medical oncologist strives to control this disease. In very specific situations, a cure may be attainable by the use of chemotherapy.
The third way is the ongoing follow-up of the “cancer survivor”. It is necessary for the medical oncologist to monitor the patient who has been successfully treated for signs of recurrence. When five years of complete remission have gone by, we can then speak of the treatment as being curative.
With regards to the medications that are available to us, there has been a notable increase in the number of agents. For decades, the mainstay of therapy was 5-Fluoracil, modulated by agents such as leucovorin. In the past few years there have been new additions to our armamentarium, including not only new cytotoxic agents such as Oxaliplatin, Irinotecan and Capecitabine, but new targeted agents such as Bevacizumab, Cetuximab and Panitumumab. There are always more agents being evaluated every day.
The explosion of the number of agents promises to give us new options in the treatment of this illness. The expectation is that we will achieve more success curing and/or controlling this disease by optimized screening and the development of new therapies. As you can tell, medical management of colorectal cancer is advancing quickly.