By Sewa S. Legha MD
HOUSTON: Colon Cancer is number-3 most frequently diagnosed cancers among the Americans and it accounts for second most frequent cause of cancer- related deaths (Lung Cancer being number 1).? Until recently colon cancer was considered an uncommon cancer in the under developed nations of the world, particularly in Africa and South Asia.? The Asian immigrants to the United States (as observed in the Japanese) do acquire an increased risk of developing colon cancer which is often attributed to adoption of Western diet and other life style behaviors including sedentary habits, increased alcohol use and possibly some unknown contributors to causing this disease.
Colon Cancer is commonly a disease of the middle aged with 90% of cases diagnosed in the age over 50 years, although it can sometimes occur in younger adults in their 20?s and 30?s.? Because this cancer begins in the mucosal lining of the colon, it can grow silently without producing any early symptoms.? Consequently, in about 25% of the cases it has already spread to internal organs like liver (Stage-4) before a clinical diagnosis is made.? The symptoms of colon cancer typically consist of change in bowel habits, with tendency? to increasing constipation, which may cause abdominal discomfort or cramps intermittently.? These tumors tend to bleed, often presenting with unexplained anemia.? Gross bleeding per rectum is not an uncommon feature of tumors located in the lower colon or rectal cancer.? More advanced tumors may cause anorexia, weight loss and fatigue due to anemia. Bowel obstruction or bowel perforation can sometimes be a presenting feature of advanced cases of colon cancer.
Screening and Early Detection of Colon Cancer:
Because colon cancer is highly curable when it is detected and removed in its early stages (stage 1 & 2), screening interventions are recommended and commonly used based on their impact in increasing survival of those who are screened as per the current recommendations.? Like other cancers, colon cancer begins insidiously and remains localized to the wall of the colon for variable period of time before it begins to spread to the regional lymph nodes (stage-3) and later on into internal organs like liver and lungs. (Stage-4).? The goal of screeing procedures is to diagnose colon cancer when it is still in stage 1 or 2 when the probability of cure is 75% to 90%.? Once the disease has progressed to stage-3, the odds of cure drop to 30%- 40%.? Stage- 4 is largely incurable unless the disease has a limited spread which may be resectable with the help of additional chemotherapy (followed by surgery).
There are several screening procedures, which have proven useful in early diagnosis.? These include digital rectal examination (useful in detecting rectal cancer), fecal occult blood testing, sigmoidoscopy, double contrast barium enema or colonscopy.? Among these procedures, colonoscopy has yielded the best results and is now recommended for all adults at the age of 50 years.? This is an outpatient procedure, which besides its diagnostic value, is also effective in removing colon polyps, which are the precursors of colon cancer.? If the colonoscopy is normal, it provides security for 10 years.? Despite its proven value, the adoption of colonoscopy in the US is still only 40% which means that 60% of the population has not complied with the current recommendations, which, if followed religiously, have the potential to save 30,000 lives per year in the US alone.
Treatment of Colon Cancer:
The mainstay of treatment of colon cancer is partial colectomy (surgical resection of a segment of colon containing the tumor). After the tumor is resected, the ends of healthy colon are united together to restore the continuity of the bowel. More than 90% of colorectal cancers can be resected without requiring a colostomy (colon connected to the skin of the abdomen and hooked up to a collection bag). Only rectal cancers typically require a colostomy. Even in these patients, primary closure is possible except in patients where the tumor is too close to the anorectal sphincter, which controls the continence of the bowel.? Surgery also plays an important role in resection of liver metastases, provided a good portion of the liver can be preserved after complete resection of the metastatic lesions (typically 1, 2 or 3 tumors)
Besides surgery, medical therapy using drugs (chemotherapy and immunotherapy) plays an important role in the management of advanced colorectal cancer.? These drugs can be used before surgery, immediately after recovery from surgery or used in patients when their disease relapses (Stage-4).? Several of the drugs used in colon cancer have been developed in the last 10-15 years and have added many years to the life of patients with advanced colon cancers. The most important chemotherapy drugs include: 5-Fluorouracil(5-FU) or its oral congener, Capecitabine(Xeloda), Irinotecan and Oxaliplatin. Besides chemotherapy, 3 additional drugs, which are a form of immunotherapy have become an important component of treatment for stage 4-colon cancer.? These drugs include, Avastin, Ceuximab and Vectibix, which are classified as monoclonal antibodies, a form of targeted therapy.
Prognosis of Colon Cancer
If detected at Stage-1, the cure rate for Colon Cancer is 90% or better.? This is only possible with the aid of colonoscopy, which can visualize early, asymptomatic cancers.? In stage-2 colon cancer, the tumor is more advanced yet is is localized to the colon wall and the cure rates with operation are 70% to 80%.? Patients with Stage-3 cancers require surgery and postoperative chemotherapy (adjuvant therapy) yet the cure rates are only 50% to 60%, with chemotherapy taking credit for 10% increase in the long tern survival. The survival of patients with metastatic cancer has steadily improved from 6-9 months without chemotherapy, to a survival of 2-3 years with the use of modern anticancer drugs.
The Indian American Cancer Network (IACAN) is committed to promote cancer awareness and prevention through education by organizing outreach events in the community.
The upcoming outreach event titled ?Colon Cancer- How Screening And Early Detection Can Be A Life Saver? will be held on Sunday, May 22 from 3-5pm at India House. The speakers are Dr. Ravi S. Mani and Aakash Gajjar.
For more information, visit www.iacannetwork .org or call 713-370-3489.
?
Short URL: http://www.indoamerican-news.com/?p=2345
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.