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Allowing for minor annual fluctuations in each year's new case total and the customary five-year, follow-up interval used for cancer survival statistics, we can see that approximately 40% of patients diagnosed with a colorectal cancer will fail to survive this condition.
While that statistic seems grim, there are some subgroups of people with colorectal cancer (and some people who might be destined to have colorectal cancer) that we should look at with the hope of substantially great cure rates. Unfortunately, there are also some subgroups with substantially worse prognoses as well.
We know that with colorectal cancer, the key to survival in most cases, at least statistically, is what is termed "early diagnosis." Early diagnosis means a cancer that is entirely confined to the intestinal wall, which is made up of several distinct layers of different tissues (such as muscle and mucous membranes). If a tumor is entirely confined to any or even all of these layers, the prognosis is quite high, in the 90% range for a permanent cure. We also know that the chance for a cure declines substantially in people whose cancer has escaped outside the bowel wall through penetration or distant spread. If a tumor has penetrated through the bowel wall into the tissues closely surrounding the bowel wall, the prognosis declines to somewhere around 50% for cure, and if the regional lymph nodes are involved the prognosis for a cure declines to the 25-35% range. If distant organ spread has occurred, for example to the liver, the chances for cure become rare indeed.
Our overall ratio of cures-to-deaths of 60% to 40% derives from all treated patients, those with early diagnosis as well as those with a late diagnosis. Because about 65% of patients with colorectal cancer present at an advanced stage, it is in everyone s interest to bring that figure down, thereby bringing the cure rate up.
Frequently Asked Questions
- How can I prevent and/or detect a colorectal cancer early?
- Right now, early detection is the key to successful cancer treatment. Screening of asymptomatic populations is the first line of defense against colorectal cancers. Seeing your doctor at the first sign of rectal bleeding or a consistent change in your bowel habits is your next step. Your doctor will best be able to judge how significant are your specific symptoms and how to best evaluate and test you.
Our best bet for prevention right now is to employ a high-fiber diet as a main dietary style. The newer drug preventions are still in the trial stage, but appear very encouraging. Be on the lookout for progress in this area in the next few years.
- Will I need a colostomy?
- Most colon and rectal cancers do not require a permanent colostomy although some do. Only your surgeon can determine this. Sometimes that determination cannot be made until the very day of surgery at the operating table.
- Will I need chemotherapy and/or radiation? Will all my hair fall out if I do?
- The requirement for these adjuvant therapies, in addition to surgery, is usually determined after the surgery is completed and a full pathology tissue report is available. Sometimes these treatments are decided upon prior to surgery in order to decrease the size of a cancer and render the cancer more readily resectable.
Various cancer treatments do, indeed, have some adverse side effects, including your hair falling out. Gastrointestinal and bone marrow effects can also occur. Or, you might not have any side effects at all. As you consider chemotherapy, those are some of the questions you would need to ask. Radiation also has some side effects to the area being treated, and your oncologist can explain that to you as well.
Preventive Measures - Prevention of colorectal cancer is a far from agreed-upon program, but studies are going on in such areas as dietary fiber intake, the use of chemicals such as calcium and aspirin, low-fat diet either alone or combined with other prevention measures. Certainly, all these areas of investigation bear watching in the future and other preventive measures will come along as time passes.
Risk Factors
Some factors leading to colorectal cancers are known. Without going into complete detail, some of these risk factors include:
- neoplastic polyps (now or in the past)
- colorectal cancer in a close relative or in several more-distant relatives
- prior cancer of the ovary, uterus or breast
- family history with familial adenomatous polyposis
- inflammatory bowel disease
- history of prior pelvic irradiation or prior colorectal cancer
What is important about screening the general population for colorectal cancer is that multiple studies have indicated that in population groups that undergo routine screening, the mortality rate from colorectal cancer can be reduced by 15 - 35% less than unscreened populations.
The Role of Polyps
One area generally agreed upon is that most colorectal cancers derive from neoplastic polyps. Polyps are common in our society. The common "adenomatous" polyp is considered to be premalignant and is thought to be present in about one-third of the population by age 50 and half of the population by age 70. The polyp-cancer relationship is so well established that our customary focus on screening has to include an attempt at diagnosing and removing colon polyps. For the past 30 years, this effort has featured polyp removal using the colonoscope instrument.
What Constitutes Screening
Screening can include anything from an annual stool blood test (fecal occult blood test) to rigid proctoscopy, or its more contemporary and effective descendent, flexible sigmoidoscopy, to a double-contrast barium enema and to the current, gold standard of complete colonoscopy. Virtual colonoscopy, using CT technology, is also being studied, though the exact role of this technique has not yet been established.
Various techniques are suitable to various individuals, and all of them have a place in the screening process. The important message to remember is that any screening is better than none at all.
Treatment for Colorectal Cancers - There is no one, single "best" treatment for all cancers of the colon and rectum. For some very early-stage cancers arising in a polyp that is mostly still benign, a simple polypectomy, such as one performed with a colonoscope, might represent adequate treatment with nothing additional required.
A more typical example, however, would be of a cancer presenting along the wall of the colon or rectum that would more likely require a formal surgical operation to remove a portion of the colon or rectum (segmental resection). Most of the segmental resection operations can be reconnected, allowing the patient to retain normal bowel function and control. Certain other resections require a colostomy, sometimes temporary, and sometimes permanent, as in the case where the cancer arises quite low in the rectum and optimal cancer treatment dictates the removal of the rectum in its entirety. As time has passed, the necessity to employ a colostomy has decreased to where today, all but a few cancers in the rectum can be managed surgically without a colostomy.
Alternatives to Surgery - Is surgery the only treatment for colorectal cancer? Trial and observation have shown that additional adjuvant therapies are of value in some of these cancers. The most commonly employed adjuvant therapies are radiation therapy and combination-drug chemotherapy. These treatments might be used prior to an operation, or after an operation, and are even sometimes given in a sandwich pattern, both pre-operatively and post-operatively. As time has proven out the value of such adjuvant therapies, patients are being offered these therapies in the face of earlier and earlier primary cancers in conjunction with their surgery. But, surgery remains the cornerstone of treatment.
Last Updated: February 23, 2007
Source: Michael F. Appel, M.D.
Texas Cancer Institute®
Colorectal Cancer - References
American Gastroenterological Association Medical Position Statement: Impact of Dietary Fiber on Colon Cancer Occurrence. Gastroenterology 2000, 118:1233-1234.
Chemoprevention of Colorectal Cancer. The New England Journal of Medicine 2000, 342:1960-1968.
The Effect of Celecoxib, A Cyclooxygenase-2 Inhibitor, in Familial Adenomatous Polyposis. The New England Journal of Medicine 2000, 342:1946-1952.
Practice Parameters for Detection of Colorectal Neoplasm. Disease of the Colon & Rectum 1999, 42:1123-1129
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