Dukes' system  Dukes' classification, first proposed by Dr Cuthbert E. Dukes in 1932, identifies the stages as:

    * A - Tumour confined to the intestinal wall

    * B - Tumour invading through the intestinal wall

    * C - With lymph node(s) involvement

    * D - With distant metastasis

  TNM system

 The most common current staging system is the TNM system, though many doctors still use the older Dukes system. The TNM system assigns a number:

 Treatment

 The treatment depends on the staging of the cancer. When colorectal cancer is caught at early stages (with little spread) it can be curable. However when it is detected at later stages (when distant metastases are present) it is less likely to be curable.

Surgery remains the primary treatment while chemotherapy and/or radiotherapy may be recommended depending on the individual patient's staging and other medical factors.

 

Surgery

 Surgeries can be categorised into curative, palliative, bypass, fecal diversion, or open-and-close.

 Curative Surgical treatment can be offered if the tumor is localized.

     * Very early cancer that develops within a polyp can often be cured by removing the polyp (i.e., polypectomy) at the time of colonoscopy.

    * In colon cancer, a more advanced tumor typically requires surgical removal of the section of colon containing the tumor with sufficient margins, and radical en-bloc resection of mesentery and lymph nodes to reduce local recurrence (i.e., colectomy). If possible, the remaining parts of colon are anastomosed together to create a functioning colon. In cases when anastomosis is not possible, a stoma (artificial orifice) is created.

    * Curative surgery on rectal cancer includes total mesorectal excision (anterior resection) or abdominoperineal excision.

 In case of multiple metastases, palliative (non curative) resection of the primary tumor is still offered in order to reduce further morbidity caused by tumor bleeding, invasion, and its catabolic effect. Surgical removal of isolated liver metastases is, however, common and may be curative in selected patients; improved chemotherapy has increased the number of patients who are offered surgical removal of isolated liver metastases.

If the tumor invaded into adjacent vital structures which makes excision technically difficult, the surgeons may prefer to bypass the tumor (ileotransverse bypass) or to do a proximal fecal diversion through a stoma. 

The worst case would be an open-and-close surgery, when surgeons find the tumor unresectable and the small bowel involved; any more procedures would do more harm than good to the patient. This is uncommon with the advent of laparoscopy and better radiological imaging. Most of these cases formerly subjected to "open and close" procedures are now diagnosed in advance and surgery avoided. 

Laparoscopic-assisted colectomy is a minimally-invasive technique that can reduce the size of the incision, minimize the risk of infection, and reduce post-operative pain.

 Cleveland Clinic colorectal surgeons developed the “no touch” technique to prevent the spread of cancer cells during colorectal surgery.

 As with any surgical procedure, colorectal surgery may result in complications including

     * wound infection, Dehiscence (bursting of wound) or hernia

    * anastomosis breakdown, leading to abscess or fistula formation, and/or peritonitis

    * bleeding with or without hematoma formation

    * adhesions resulting in bowel obstruction (especially small bowel)

    * blind loop syndrome as in bypass surgery.

    * adjacent organ injury; most commonly to the small intestine, ureters, spleen, or bladder

    * Cardiorespiratory complications such as myocardial infarction, pneumonia, arrythmia, pulmonary embolism etc

 

Chemotherapy

 Chemotherapy is used to reduce the likelihood of metastasis developing, shrink tumor size, or slow tumor growth. Chemotherapy is often applied after surgery (adjuvant), before surgery (neo-adjuvant), or as the primary therapy if surgery is not indicated (palliative). The treatments listed here have been shown in clinical trials to improve survival and/or reduce mortality rate and have been approved for use by the US Food and Drug Administration. 

    * Adjuvant (after surgery) chemotherapy. One regimen involves the combination of infusional 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX)

          o 5-fluorouracil (5-FU) or Capecitabine (Xeloda®)

          o Leucovorin (LV, Folinic Acid)

          o Oxaliplatin (Eloxatin®)

     * Chemotherapy for metastatic disease. Commonly used first line chemotherapy regimens involve the combination of infusional 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) with bevacizumab or infusional 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) with bevacizumab

          o 5-fluorouracil (5-FU) or Capecitabine

          o Leucovorin (LV, Folinic Acid)

          o Irinotecan (Camptosar®)

          o Oxaliplatin (Eloxatin®)

          o Bevacizumab (Avastin®)

          o Cetuximab (Erbitux®)

          o Panitumumab (Vectibix)

 

    * In clinical trials for treated/untreated metastatic disease.

          o Bortezomib (Velcade®)

          o Oblimersen (Genasense®, G3139)

          o Gefitinib and Erlotinib (Tarceva®)

          o Topotecan (Hycamtin®)

 

Radiation therapy 

Radiotherapy is not used routinely in colon cancer, as it could lead to radiation enteritis, and it is difficult to target specific portions of the colon. It is more common for radiation to be used in rectal cancer, since the rectum does not move as much as the colon and is thus easier to target. Indications include:

     * Colon cancer

          o pain relief and palliation - targeted at metastatic tumor deposits if they compress vital structures and/or cause pain

    * Rectal cancer

          o neoadjuvant - given before surgery in patients with tumors that extend outside the rectum or have spread to regional lymph nodes, in order to decrease the risk of recurrence following surgery or to allow for less invasive surgical approaches (such as a low anterior resection instead of an abdomino-perineal resection)

          o adjuvant - where a tumor perforates the rectum or involves regional lymph nodes (AJCC T3 or T4 tumors or Duke's B or C tumors)

          o palliative - to decrease the tumor burden in order to relieve or prevent symptoms

 Sometimes chemotherapy agents are used to increase the effectiveness of radiation by sensitizing tumor cells if present.

 

Immunotherapy

 Bacillus Calmette-Guérin (BCG) is being investigated as an adjuvant mixed with autologous tumor cells in immunotherapy for colorectal cancer.

Vaccine

In November 2006, it was announced that a vaccine had been developed and tested with very promising results. The new vaccine, called TroVax, works in a totally different way to existing treatments by harnessing the patient's own immune system to fight the disease. Experts say this suggests that gene therapy vaccines could prove an effective treatment for a whole range of cancers. Oxford BioMedica is the company behind the vaccine; it's a British company established as a spin-out from Oxford University and specialises in the development of gene-based treatments. Further vaccine trials are underway.

  Treatment of colorectal cancer metastasis to the liver

According to the American Cancer Society statistics in 2006 greater then 20% of patients present with metastatic (stage IV) colorectal cancer at the time of diagnosis, and up to 25% of this group will have isolated liver metastasis that is potentially resectable. Lesions which undergo curative resection have demonstrated 5-year survival outcomes now exceeding 50%.

Resectability of a liver met is determined using preoperative imaging studies (Ct or MRI), intraoperative ultrasound, and by direct palpation and visualization during resection. Lesions confined to the right lobe are amenable to en bloc removal with a right hepatectomy (liver resection) surgery. Smaller lesions of the central or left liver lobe may sometimes be resected in anatomic "segments", while large lesions of left hepatic lobe are resected by a procedure call hepatic trisegmentectomy. Treatment of lesions by smaller,non-anatomic "wedge" resections is associated with higher recurrence rates. Some lesions which are not initially amenable to surgical resection may become candidates if they have signifigant responses to preoperative chemotherapy or immunotherapy regimines. Lesions which are not amenable to surgical resection for cure can be treated with modalities including radio-frequency ablation (RFA), cryoablation, and chemoembolization.

Patients with colon cancer and metastatic disease to the liver may be treated in either a single surgery or in staged surgeries (with the colon tumor traditionally removed first) depending upon the fitness of the patient for prolonged surgery, the difficulty expected with the procedure with either the colon or liver resection, and the comfort of the surgery performing potentially complex hepatic surgery.

Poor pronostic factors of patients with liver metastasis include

    * Synchronous (diagnosed simultaneously) liver and primary colorectal tumors

    * A short time between detecting the primary cancer and subsequent development of liver mets

    * Multiple metastatic lesions

    * High blood levels of the tumor marker, carcino-embryonic antigen (CEA), in the patient prior to resection

    * Larger size metastatic lesions

 

Support therapies

Cancer diagnosis very often results in an enormous change in the patient's psychological wellbeing. Various support resources are available from hospitals and other agencies which provide counseling, social service support, cancer support groups, and other services. These services help to mitigate some of the difficulties of integrating a patient's medical complications into other parts of their life.

 

Prognosis

 Survival is directly related to detection and the type of cancer involved. Survival rates for early stage detection is about 5 times that of late stage cancers. CEA level is also directly related to the prognosis of disease, since its level correlates with the bulk of tumor tissue.

 Follow-up

 Follow-up aims at diagnosing metachronous lesion(s) or distant metastasis in the early stage. History taking and physical examination every 3 to 6 months for three years after surgery. CEA every 2 to 3 months for two or more years in patients who have had resection of liver metastasis. Colonoscopy looking for synchronise lesion(s) should be done shortly after surgery if preoperatively the scope cannot pass through the tumor; otherwise it should be done every 3 to 5 years. ASCO recommends against other routine follow-up tests such as Chest X-Ray, Ultrasound, CT, etc.

 Prevention

 Most colorectal cancers should be preventable, through increased surveillance, improved lifestyle, and, probably, the use of dietary chemopreventative agents.

 

Surveillance

 Most colorectal cancer arise from adenomatous polyps. These lesions can be detected and removed during colonoscopy. Studies show this procedure would decrease by > 80% the risk of cancer death, provided it is started by the age of 50, and repeated every 5 or 10 years.

 As per current guidelines under National Comprehensive Cancer Network, in average risk individuals with negative family history of colon cancer and personal history negative for adenomas or Inflammatory Bowel diseases, flexible sigmoidoscopy every 5 years with fecal occult blood testing annually or double contrast barium enema are other options acceptable for screening rather than colonoscopy every 10 years (which is currently the Gold-Standard of care).

 Lifestyle

 The comparison of colorectal cancer incidence in various countries strongly suggests that sedentarity, overeating (i.e., high caloric intake), and perhaps a diet high in meat (red or processed) could increase the risk of colorectal cancer. In contrast, physical exercise, and eating plenty of fruits and vegetables would decrease cancer risk, probably because they contain protective phytochemicals. Accordingly, lifestyle changes could decrease the risk of colorectal cancer as much as 60-80%.

 

 Chemoprevention

 More than 200 agents, including the above cited phytochemicals, and other food components like calcium or folic acid (a B vitamin), and NSAIDs like aspirin, are able to decrease carcinogenesis in preclinical models: Some studies show full inhibition of carcinogen-induced tumours in the colon of rats. Other studies show strong inhibition of spontaneous intestinal polyps in mutated mice (Min mice). Chemoprevention clinical trials in human volunteers have shown smaller prevention, but few intervention studies have been completed today. Calcium, aspirin and celecoxib supplements, given for 3 to 5 years after the removal of a polyp, decreased the recurrence of polyps in volunteers (by 15-40%). The "chemoprevention database" shows the results of all published scientific studies of chemopreventive agents, in people and in animals.

 

Aspirin chemoprophylaxis

 Aspirin should not be taken routinely to prevent colorectal cancer, even in people with a family history of the disease, because the risk of bleeding and kidney failure from high dose aspirin (300mg or more) outweigh the possible benefits.

 A clinical practice guideline by the U.S. Preventive Services Task Force (USPSTF) recommended against taking aspirin (grade D recommendation). The Task Force acknowledged that aspirin may reduce the incidence of colorectal cancer, but "concluded that harms outweigh the benefits of aspirin and NSAID use for the prevention of colorectal cancer". A subsequent meta-analysis concluded "300 mg or more of aspirin a day for about 5 years is effective in primary prevention of colorectal cancer in randomised controlled trials, with a latency of about 10 years". However, long-term doses over 81 mg per day may increase bleeding events.

 Calcium

 A meta-analysis by the Cochrane Collaboration of randomized controlled trials published through 2002 concluded "Although the evidence from two RCTs suggests that calcium supplementation might contribute to a moderate degree to the prevention of colorectal adenomatous polyps, this does not constitute sufficient evidence to recommend the general use of calcium supplements to prevent colorectal cancer.". Subsequently, one randomized controlled trial by the Women's Health Initiative (WHI) reported negative results. A second randomized controlled trial reported reduction in all cancers, but had insufficient colorectal cancers for analysis. 

 

 

 

 

 

 

 

 

 

 

 

 

Associate Links -  

Computer Animation | 3D Renderings | Health Care | Hair Transplant | Graphic Design | 3D Interior Design | 3D Furniture Design | Ford Quotes | Jewelry Design | Cancer Support | Attorney | Fashion Design | Real Estate | Business Card | Design | Personal Loan | Plastic Surgery | Charity for Children | Mihan | Business Attorney | 3D Animation | Free 3D Models | Graphic Design School | Interior Design | Construction Today |  what is online | Finance India | Design Jewelry | Reiki | Yoga | Nagpur Mihan Chartered Accountant | Nagpur Mihan | Health Forums  | Jewelry Store Catalog | DUI Lawyers |  Latest Jewelry Design |  Ayurveda |  Chikhaldara |   Online Yoga |   Wikipedia |