Thursday, June 2, 2011
Friday, January 19, 2007
are the same, yet different. While the biology of colon cancer and
rectal cancer are the same, the clinical implications of the location
of a cancer are great. This entry discusses the anatomical differences between the colon and the rectum.
Pathologists generally use the "fanning out" of taenia coli as the
beginning of the rectum. Taenia coli are separate longitudinal
ribbons of smooth muscle on the outside of the ascending, transverse,
descending and sigmoid colons. They are visible, and can be seen just
below the serosa. They generally disappear above the level of the
sacral promontory. This anatomic division is important for three
1) The lymphatic drainage of the rectum can change to entirely
different pathway (cancer of the rectum can spread via a different pathway than cancer of the colon)
2) The rectum is closely related to the bones of the pelvis (cancers of the rectum invading into the pelvic bones generally cannot be removed in total with surgery except under some
3) The rectum is adjacent to the muscular floor of the pelvis and the
nerves which control it, which are responsible for allowing one to
control their bowel movements (removal of cancers of the rectum can radically affect or remove ones ability to control their bowel resulting in fecal incontinence)
Cancers of the colon, even if they invade through the wall of the
colon, rarely invade into bone, or into other structures that cannot
be resected. These cancers predictably spread first to the colon lymph nodes, then to the liver, and then beyond (lungs is the next most common). Resection of the colon usually does not alter ones continence, although the bowel movements may become more loose with extensive colon resection.
Wednesday, January 17, 2007
"I was diagnosed with stage IIA colorectal cancer last August, a few months before my 31st birthday...I worry because few people develop this cancer as early as I did. There is no history of cancer in my family. I have been a lacto-ovo vegetarian since I was 18 years old. Do you have any recommendations for how I can prevent recurrence? Could this have been a fluke?"
Differences in Colorectal Cancer in the Young and OldThere is a slight correlation between age at diagnosis and the types of genetic mutations present in colorectal cancer. Cancer in younger people also tends to occur more often on the right side of the colon than the left. We used to think that colorectal cancers in younger people were more aggressive, but this has not proven to be the case. These slight differences don't change the fact that most people diagnosed with colorectal cancer do not have a family history of it and do not have an inherited syndrome associated with it.
PreventionThe problem faced currently is diagnosis of precancerous polyps and cancers in people under the age of 50 who have no family history, because people in this category are not generally being screened with endoscopy. The guidelines for screening put forth by every major organization with an interest in this area do not recommend screening colonoscopy or sigmoidoscopy in this group of patients. For this reason, we rely on this group of patients to be evaluated when they have symptoms that suggest a potential problem such as blood in the stool, unintentional weight loss, loss of appetite, or chronic anemia. Many investigators are working on DNA tests that would help to identify patients at higher risk of colorectal cancer, but these are still early in development.
At the current time, the ways of preventing polyps and colorectal cancer do not differ between young and old patients. Regular surveillance with endoscopy if a patient has a history of colon cancer or polyps is critical. In addition, patients with a history of breast, ovarian, endometrial cancer, or inflammatory bowel disease may be at higher risk for colon cancer and should be screened. All patients with a family history, personal history, or other risk factors for polyps or cancer should discuss with their physician the appropriate tests and intervals for cancer surveillance. In the abscence of risk factors, most organizations recommend initial screening of the colon at age 50.
For chemoprevention, see the previous blog, Chemoprevention and Colorectal Cancer.
Tuesday, January 16, 2007
Preoperative chemoradiation therapy plays a role in some stage II cancers if they are in the rectum. Patients may receive approximately 5 week course of this therapy to shrink the tumor which often increased the success of the surgery that follows. The use of chemotherapy in stage II colon cancer is controversial and is not the standard of care at this point in time so most patients with stage II colon cancer will not receive chemotherapy unless they are enrolled in a clinical trial evaluating the efficacy of chemotherapy.
Most patients with this stage of cancer are cured after undergoing treatment.
Sunday, January 14, 2007
You can locate a colon & rectal surgery specialist through the American Society of Colon & Rectal Surgeons.
Friday, January 5, 2007
Peristomal Skin ProblemsSkin problems associated with a stoma can be caused for a number of reasons. Fungal infections are a common cause of red rash under the stoma appliance and bag because the area is often moist. Often this type of rash will extend down any skin creases. This can be treated using antifungal medications.
Some patients will develop an allergy to the appliance adhesives which causes a reaction only in the area that the adhesive touches. Changing the stomahesive often times cures this.
Poorly fitting stomas can allow leakage from the intestine onto the skin which causes skin irritation which can range from a mild redness to severe ulceration. Leakage can happen for a number of reasons. Sometimes it is because the appliance is cut to the wrong size or an inadequate amount of stoma paste is being used. Other times, anatomical problems with the stoma cause this such as the stoma being located in a skin crease or retraction of the stoma which make pouching difficult.