Colorectal Cancer | Cancer.Net

Colorectal Cancer Live Chat with Michael J. O'Connell, MD
Friday, March 7, 2003, 3:00 - 4:00 PM ET
About Michael J. O'Connell, MD

Dr. O'Connell is Director of the Allegheny Cancer Center and the Division of Medical Oncology at Allegheny General Hospital in Pittsburgh, Pennsylvania. He also serves as Associate Chairman of the National Surgical Adjuvant Breast and Bowel Project (NSABP). He is Professor of Human Oncology at Drexel University College of Medicine and the physician coordinator of national phase III clinical trials in gastrointestinal cancer sponsored by the National Cancer Institute. He is Co-Chair of the Clinical Trials Task Force of the National Dialogue on Cancer.

Dr. O'Connell is a member of Cancer.Net's Editorial Board.

Dr. O'Connell wanted to emphasize some points that were not discussed during the chat and expand upon some questions that were asked. His statement is posted here, just before the beginning of the chat.

Introductory Statement to Live Web Chat
Michael J. O'Connell, MD
Colorectal cancer is a disease that will afflict nearly 150,000 Americans in 2003. The number of people dying from this disease has been decreasing in recent years, probably due to improvements in cancer detection and treatment. Some important points to consider:

Colorectal cancer is not a death sentence

If caught early, this disease is highly curable with surgery. Chemotherapy (and in some cases radiation therapy) can further increase cure rates for patients with moderately advanced tumors. Radiation therapy is most beneficial in the treatment of rectal cancer, which has a higher chance of coming back in the same region of the body after surgery.

Deaths from colorectal cancer can be prevented

Colorectal cancer typically develops over a period of several years. More than 90% of people who get colorectal cancer are over 50 years of age. Studies have shown that regular screening with tests such as looking for blood in the stool ("fecal occult blood"), and examining the large bowel with a lighted instrument (sigmoidoscope or colonoscope) can decrease the risk of dying from this disease. It is recommended that screening tests begin at age 50 for people at average risk of developing colorectal cancer, or at a younger age if there is a positive family history. Current research is determining whether looking for molecular abnormalities in the stool (mutations in cells shed from the bowel wall) will be more accurate in detecting colorectal cancer or polyps than searching for blood in the stool. A sophisticated computed tomography (CAT) scan x-ray device which can produce images of the inside of the colon and rectum without the need for inserting a tube into the rectum is also being studied in clinical trials ("virtual colonoscopy") to see how effective it will be in finding polyps or tumors.

Genetic testing is now available for people in families with certain hereditary forms of colorectal cancer

About 1% of people who get colorectal cancer in the United States have a condition known as familial adenomatous polyposis (FAP). About 5% have hereditary non-polyposis colorectal cancer (HNPCC). There is a strong family history of colorectal cancer associated with each of these inherited conditions. Specific genetic tests have been developed which can help determine the chance that an individual member of such families might get colorectal cancer. These tests are not generally helpful in the absence of a positive family history for these conditions, and should be performed only after consultation by a medical geneticist.

A diagnosis of colorectal cancer does not mean that a colostomy will be necessary

Only a small proportion of patients with colorectal cancer require a colostomy (an opening made in the abdomen to allow stool to be collected in an external bag). Modern surgical techniques such as coloanal anastomosis can avoid the need for a colostomy for some patients with rectal cancer. Improved staging techniques have made it possible to remove some rectal cancers through the anus without the need for a major surgical procedure while still preserving an excellent chance of cure.

New chemotherapy drugs are available which have improved the treatment of advanced colorectal cancer

When cancers spread to distant parts of the body they are referred to as "metastatic." Although a small number of people with metastatic colorectal cancer can be cured with surgery, most will be treated with chemotherapy drugs in an attempt to control the disease for as long as possible. For many years, only the drug known as fluorouracil (5FU) was effective in shrinking metastatic colorectal tumors. More recently, the drugs irinotecan and oxaliplatin have been shown to be beneficial, and have been approved by the U.S. Food and Drug Administration for the treatment of colorectal cancer. Capecitabine is a drug which comes in pill form that can help some patients, and is generally less toxic than intravenous chemotherapy. The most effective drug combination developed to date, based on large randomized clinical trials, is the combination of oxaliplatin, 5FU, and leucovorin. New experimental drugs that block molecules such as the epidermal growth factor (EGF), a molecule which stimulates growth of colorectal tumor cells in the body, are being tested in clinical trials. These targeted treatments have the potential to be more effective than traditional chemotherapy with fewer side effects, but any benefit to patients with colorectal cancer must be proven in clinical trials. Other investigational approaches to treating this disease include the use of drugs which block blood vessel formation (angiogenesis inhibitors) and the use of tumor vaccines.

Colorectal cancer is a preventable disease

Most colorectal cancers arise from polyps, which are benign growths of the lining of the colon or rectum that can become cancerous over time. If polyps are detected and removed, the chance of getting colorectal cancer can be decreased. It is also known that diets that are low in fat and contain lots of fresh fruits and vegetables are associated with a lower risk of colorectal cancer. Exercising, avoiding cigarettes altogether, and avoiding heavy alcohol intake can also lower the risk. Recent studies have indicated that aspirin can decrease the risk of polyps in people that have had colon polyps or colon cancer in the past. Since aspirin can have serious side effects (for example bleeding), and the amount of reduction in polyps is modest, aspirin is not recommended in the general population to prevent colon cancer. Newer drugs known as COX 2 inhibitors (such as rofecoxib and celecoxib) and are being studied in clinical trials to determine whether they will be more effective and less toxic than aspirin to prevent colorectal cancer.

There have been many advances in the management of colorectal cancer in the past few years. Patients and their families should discuss these innovations with their physician to determine what tests or treatments would be most appropriate for their individual circumstances.

Moderator: On behalf of the American Society of Clinical Oncology (ASCO), welcome to the Cancer.Net chat on colorectal cancer, a live question-and-answer session hosted by Michael J. O'Connell, MD. During this hour, Dr. O'Connell will answer as many questions as time permits. Some questions may be adapted so Dr. O'Connell's answers can help as many people as possible.

Dr. O'Connell will take questions from 3:00 PM to 4:00 PM ET. As you prepare your questions, please keep in mind that Dr. O'Connell is unable to give individual medical advice in this setting. In answering questions about specific drugs, Dr. O'Connell's comments will focus on the state of current research and clinical trials.

This chat is governed by all terms and conditions of the Cancer.Net website.

Good afternoon everyone, and welcome. Thanks for logging on. Dr. O'Connell will now begin taking questions.

Guest184: For patients with stage III cancer, what sort of treatments can be expected? What is the death rate?

Dr. O'Connell: Patients with stage III (Dukes C or Node Positive) colon cancer generally benefit from postoperative adjuvant chemotherapy. Treatments such as fluorouracil (5FU) combined with leucovorin can decrease the risk of recurrence by 30% to 40%.

The death rate depends upon the number of lymph nodes involved. Over 50% of patients with one to three positive nodes can be cured with surgery and chemotherapy. Approximately 40% of patients with four or more positive nodes can be cured with surgery and chemotherapy.

pisceswomyn: Can colon cancer lead to rectal cancer?

Dr. O'Connell: Patients who have had colon cancer have a higher risk of developing a new cancer in the large bowel, which includes the rectum.

The risk depends on hereditary factors. For example, some families have a very high risk of developing a second cancer. If there is no familial history, the risk of developing a second cancer of the large bowel is approximately 5%.

Cassie: When looking for an oncologist to handle this type of cancer, are there any steps that family members should take before making a final decision?

Dr. O'Connell: Patients with colorectal cancer are generally cared for by colorectal surgeons or general surgeons with a particular interest in this disease for their surgical management.

Large cancer centers generally have medical oncologists who subspecialize in treatment of different types of cancer. Therefore, seeking a medical oncologist with a subspecialty in colorectal cancer would be the best strategy.

Suzy: My grandmother died of colon cancer at 50. I am 33, should I begin screening now or when I'm 40?

Dr. O'Connell: If there were no other cases of colon cancer in your family, we would recommend beginning screening at age 40. If there are other members of your immediate family who have had colon cancer, particularly at a young age, it may be indicated to begin screening now.

Guest184: Friends have said I need to get into a clinical trial right away. Where can I sign up for one?

Dr. O'Connell: Clinical trials for colorectal cancer are available throughout the country through the cooperative group mechanism sponsored by the National Cancer Institute. The trials are available both at large cancer centers and at community facilities.

You should inquire from your oncologist whether he or she participates in clinical trials.

TonyD: What about the news about aspirin preventing colon cancer? How does it do that? Should I be taking aspirin?

Dr. O'Connell: First, two papers were published in the March 6, 2003 issue of the New England Journal of Medicine which reported that aspirin can decrease the incidence of recurrent polyps in patients with a history of colon cancer or colon polyps. The study did not prove that colon cancer itself was prevented. This will require longer follow up to determine whether decreasing the incidence of polyps will translate to a decrease of colon cancer.

Aspirin decreases the synthesis of chemicals known as prostaglandins, which stimulate the growth of cells in the lining of the colon. The authors of the papers and accompanying editorial did not recommend use of aspirin for prevention of colon cancer in the general population at this point in time.

The impact on polyps was modest, and there is a risk of bleeding and other side effects from aspirin.

Suzy: How effective is a barium enema as a screening tool for colon cancer?

Dr. O'Connell: The barium enema can be effective in detecting large polyps or colon cancer. It is not as effective as endoscopy (sigmoidoscopy or colonoscopy). It is sometimes used in combination with sigmoidoscopy to screen for colon cancer.

InCal: My father has colon cancer and his doctors are saying that treatment has stopped working. Can this be true? What should he expect next?

Dr. O'Connell: I assume that your father has cancer that has spread to distant sites of his body, from the nature of your question. Even when chemotherapy treatments are effective for metastatic colon cancer, the tumor becomes resistant. That is, the cancer cannot be cured.

There may be experimental treatments on a clinical trial, which could be of benefit, depending upon his overall condition. Alternatively, comfort measures such as pain control and nursing care may be most helpful.

MayBirthday: How does diet impact the risk for colon cancer? Any foods to avoid or increase?

Dr. O'Connell: It has been estimated that 30% of the risk of developing colon cancer may be related to diet. Diets high in calories and saturated fats, and low in fresh fruits and vegetables are associated with the highest risks.

Deloris: Should I have my daughter tested for the cancer gene?

Dr. O'Connell: There are many genes that may be abnormal in patients with cancer. Regarding colorectal cancer, there are two conditions associated with specific genetic abnormalities. The first is familial adenomatous polyposis (FAP).

In this condition, there are hundreds to thousands of polyps that occur throughout the large bowel. If the polyps are not removed, they will turn into cancer in 100% of individuals affected.

There is a specific gene located on chromosome 5, which is mutated in this condition. If you have a family history of this condition, it would be worthwhile for you to be tested for the APC gene. This condition is very rare and only accounts for 1% of colorectal cancer in the United States.

The second condition is known as hereditary non-polyposis colorectal cancer (HNPCC). This condition accounts for perhaps 5% of colorectal cancer cases in the United States.

At least three family members are affected by colon cancer in HNPCC kindreds. There are specific genes (MLH1, MSH2) which can be mutated in this condition. If you have a family history of HNPCC, having these gene tests done could be beneficial. In the absence of positive family history, genetic testing is not helpful to screen for colorectal cancer.

Guest128: After a surgical resection of a stage I colon cancer without node involvement, is any other treatment needed?

Dr. O'Connell: Since the surgical cure rates exceed 90%, there is not an indication for additional treatment.

pisceswomyn: What is metastatic colon cancer?

Dr. O'Connell: Metastatic colon cancer refers to the situation when cancer cells have spread from the colon to distant sites in the body. The lymph nodes, the lungs, and the liver are common areas that may be affected.

badoodies: I just heard about oxaliplatin, is it an effective treatment option for metastatic colorectal cancer?

Dr. O'Connell: Oxaliplatin was approved by the FDA for the treatment of advanced colorectal cancer in August 2002. When combined with the chemotherapy drugs 5FU and leucovorin, oxaliplatin has shown superior tumor response rates and duration of control of metastatic disease compared to other commonly used regimens.

It is not a cure for metastatic colorectal cancer, but in some cases has produced enough shrinkage of tumors in the liver to allow surgical removal. It is being studied as an "adjuvant" treatment following surgery for primary colon cancer to determine whether it will improve the cure rates. The results of these studies are not yet available.

Guest143: Can herbs cure cancer?

Dr. O'Connell: Herbs can contain chemicals that have the ability to affect the growth of tumors. There are no herbs that I am aware of that can cure cancer. Problems with the use of herbs include the possibility of severe side effects and adverse interaction with chemotherapy drugs.

foster: What is your advice to someone with stage IV rectal cancer who just "failed" capecitabine?

Dr. O'Connell: The answer depends upon a number of factors. These include what the patient's condition is at the present time. For example, people who are not eating well and are bedridden generally do not benefit from further chemotherapy.

Likewise, if the blood counts are very low, there could be difficulties with bleeding or infections. If the patient is in good condition, then drugs such as oxaliplatin or irinotecan could be considered.

Guest65: What causes colon cancer? I am a 63-year-old white male. I exercise, watch my diet, and only drink one glass of red wine per night.

Dr. O'Connell: The cause of colon cancer is not known for most individuals. A small percentage develop colon cancer due to specific genetic mutations. Risk factors that increase the chance of developing colon cancer include lack of exercise, obesity, smoking, or excessive alcohol intake.

In addition, individuals with inflammatory bowel disease, such as ulcerative colitis, have a higher risk of developing colon cancer. Some people will develop colon cancer for reasons that we do not understand, even though they do not have any identifiable risk factors.

Arthur: We've been told that CEA testing can miss recurrent colon cancer. Are there any new blood tests that are more accurate?

Dr. O'Connell: There are a number of new molecular tests to detect colon cancer that are under development. The results of studies of these new markers have been promising in some cases, but there is not general consensus that any of them should be used in standard clinical practice.

Guest143: I read on the Cancer.Net site that there is a vaccine for cancer. Can you explain?

Dr. O'Connell: Immunotherapy is a new method of cancer treatment which is intended to use the patient's own immune system to fight the cancer. One strategy that is being investigated in clinical trials is the use of tumor vaccines. The theory is similar to the use of vaccines to treat or prevent infectious diseases, but the effectiveness of tumor vaccines for colorectal cancer has not yet been proven.

pisceswomyn: Will anti-inflammatory drugs react adversely with chemotherapy treatment?

Dr. O'Connell: Anti-inflammatory drugs can be associated with certain side effects such as irritation of the stomach. If this occurred in a patient taking chemotherapy, it could predispose to gastrointestinal bleeding. Therefore, these drugs should be carefully monitored if given with chemotherapy.

Guest17: I have stage IIB colon cancer. What is a stage?

Dr. O'Connell: Staging refers to the extent of the cancer within the body. A detailed summary of staging of colon cancer is posted on the Cancer.Net website. Stage IIB colon cancer is moderately advanced in that the tumor has penetrated through the wall of the colon. Depending upon other risk factors, the use of chemotherapy may be indicated to decrease the risk of recurrence.

BrentB: Is everyone with metastatic colon cancer given the same drug regimen? How do they decide?

Dr. O'Connell: The most effective chemotherapy regimens for colon cancer involve the use of several drugs in combination. The response rates are higher and the period of disease control is longer. However, the treatments also have more side effects.

If the patient is felt to be at low risk of experiencing severe side effects, one of the combination regimens such as oxaliplatin plus 5FU plus leucovorin would be indicated. In a weak or elderly patient, the use of less toxic oral chemotherapy with a drug such as capecitabine may be a better alternative.

Molly: With polyps or colorectal cancer, is a growth ever visible outside the body?

Dr. O'Connell: The polyps or primary colorectal cancer are generally not visible outside the body. If the cancer has spread, then there could be a lump or mass visible over parts of the body such as the abdomen or above the collarbone.

Carlie: Will there ever be a cure for colon cancer?

Dr. O'Connell: Colon cancer can be cured in many patients today. The earlier the disease is diagnosed, the higher the cure rate. With the removal of polyps, the incidence of colon cancer can be significantly reduced.

The hope for the future is the development of effective chemoprevention which may be able to prevent the disease from occurring in the first place.

Moderator: The chat is now ending. Thank you for your thoughtful questions. We hope this discussion has been valuable, and we regret not being able to answer every question. Dr. O'Connell, thanks again for lending us your time and expertise.

More information is available in the Cancer.Net colorectal cancer section.

SAVE THE DATE: The Cancer Clinical Trials live chat with Robert Comis, MD, has been rescheduled for March 17, 2003 from 4:30 PM to 5:30 PM ET. Dr. Comis is President and Chairman, Coalition of National Cancer Cooperative Groups, Inc., and Professor of Medicine and Director of the MCP Hahnemann University Clinical Trials Research Center, Philadelphia. He is a member of ASCO's Board of Directors.

The chat room is now closed. Thanks again for joining us.