Epidemiology
Colorectal Cancer (CRC) is the 3rd most common malignancy in the United States and the 2nd most common cause of cancer death in the US. In 2005 there were 145,000 new cases of CRC in the US. Approximately 56,000 deaths occur per year from CRC. In Kentucky there were 15,802 cases of CRC from 1995-2003 and 7,290 colon cancer deaths during the same time period.
Risk factors for CRC are important to understand but approximately 75% of CRC cases are sporadic. The incidence of CRC increases with age with greater than 90% occurring after age 50. Less than 6% of CRC cases occur before age 40. Other risk factors are family history, personal history of an advanced polyp, certain hereditary forms of colon cancer, and inflammatory bowel disease.
It is estimated that CRC mortality could be reduced by 28% to 60% and CRC incidence reduced by 17 to 54% if 75% of the eligible population were screened. However a recent survey found that less than 50% of adults aged 50 or older have had any CRC screening within the recommended time intervals. The awareness of colorectal cancer screening is increasing however and efforts such as CRC awareness month and the Colon Cancer Prevention Project (see CCPP guidelines) are vitally important.
Screening options are varied and include fecal occult blood testing, fiber- optic sigmoidoscopy, double contrast barium enema, CT colonography and colonoscopy. Colonoscopy is often quoted as the best screening strategy but it is not perfect, is costly and obviously not performed in approximately 50% of eligible patients for various reasons.
Most colon cancers arise from adenomatous polyps, the so-called adenoma to carcinoma sequence. Only 5% of adenomas will develop into CRC but most, if not all, colorectal cancers arise from polyps. It is estimated that there is normally a 5 to 10 year dwell (lag) time between development of a 1cm polyp and CRC. This is the reasoning behind performing colonoscopies every 10 years (if normal).
Formal guidelines for CRC screening were published in 1994 by an expert panel of Gastroenterologists and Colo-Rectal Surgeons. These guidelines have been routinely updated and are reviewed in the 2009 Colon Cancer Prevention Project tip sheet (see above).
Clinical Presentation
Universal screening for CRC would be ideal but obviously this is not likely to happen anytime soon. Patients still present with colorectal cancers and have never been screened or had some type of screening procedure years ago. The most common symptoms of patients with CRC are abdominal pain (47%), rectal bleeding (30%), unexplained anemia (18%), constipation (20%) and diarrhea (16%). There is a progression of tumors from the rectum toward the right colon. Right sided cancers rarely cause obstruction but tend to be larger and present with iron deficient anemia. Left colon cancers more often present with obstructive symptoms and bleeding.
Surgery
Most but not all colorectal cancers can be resected at the time of surgery. Traditional open techniques are still used but laparoscopic colon resection is often preferable and has the advantages of smaller incisions, less pain and decreased pain medications, less time in the hospital and quicker recovery time. The recurrence and cure rates are the same as open colectomy.
Adjuvant Therapy
Early stage (Stage 1) colorectal cancers are often cured with surgery alone. More advanced cancers (Stage 2 & 3) often have improved survival rates when treated with adjuvant chemotherapy. Neoadjuvant (pre-op) chemotherapy is often recommended for advanced colorectal cancers. Radiation therapy is usually reserved for rectal cancers.
Survival
Long term survival in CRC patients is stage and treatment dependent. Obviously the best treatment is early detection and removal of polyps.
Summary
Most colon and rectal cancers arise from polyps in the colon. The majority of polyps can be detected and removed during a colonoscopy which usually prevents the development of cancer. If cancer is found in the colon during colonoscopy it is usually necessary to have it surgically removed.
The surgeons at Capital Surgical Clinic provide screening and therapeutic colonoscopies as well as surgical options to include laparoscopic colon resection. We have an excellent working relationship with Medical and Radiation Oncologists and will coordinate all aspects of your care.
If you have not had your colonoscopy, call us today to schedule an office evaluation and potential colonoscopy.
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