All right, now, the colon has four parts, called the ascending colon, which runs up on the right side of the abdomen; the transverse colon, which runs across the upper part of the abdomen; the descending colon, which runs down the left side of the abdomen; and finally the sigmoid colon, which is the S-shaped part that joins the rectum.
Let’s zoom into the wall of the large intestine, which is made up of four layers. The outermost layer is called serosa or adventitia. Next is the muscular layer, which contracts to move food through the bowel. After that is the submucosa, which consists of a dense layer of tissue that contains blood vessels, lymphatics, and nerves. And finally, there’s the innermost layer, called the mucosa, which consists of simple columnar epithelium spanned by goblet cells. This mucosa forms invaginations called colonic crypts or glands.
Now colorectal cancer occurs when any of these epithelial cells acquire a mutation in the adenomatous polyposis coli or APC genes, which are tumor suppressor genes, meaning that they suppress the growth of tumor cells. This mutation leads to the formation of a small polyp, also called early adenoma. Later on, these polyps may develop further mutations, such as KRAS or p53 gene mutations, leading to the development of colon cancer.
Mutations may arise due to a variety of risk factors. Modifiable risk factors include smoking, obesity, and a diet high in processed meat, and excessive alcohol intake. On the other hand, nonmodifiable risk factors include age above 40, family history of colorectal cancer or colorectal polyps, in addition to hyperinsulinemia and inflammatory bowel disease, including Crohn disease and ulcerative colitis.
So, once an epithelial cell becomes mutated and cancerous, it starts dividing uncontrollably, forming a tumor mass. As the tumor keeps growing, new blood vessels also develop via angiogenesis to supply it. Eventually, cancerous cells start invading neighboring tissues, and may even spread to nearby lymph nodes, or metastasize to distant organs, such as the brain, bones, or liver.
Now, the clinical manifestations of colorectal cancer vary based on the size and location of the tumor. Initially, clients can be completely asymptomatic. Over time, the body mounts an immune response to fight the tumor off, so clients may start experiencing unintentional weight loss, fever, and malaise.
If the tumor grows enough to physically obstruct the bowel, it can cause narrowing of the intestinal lumen, obstruction, colicky pains, constipation or diarrhea, as well as decreased caliber or narrowing of the stool, hematochezia or fresh blood with the stool, and iron deficiency anemia.
Diagnosis of colorectal cancer starts with history and physical assessment, followed by colonoscopy with biopsy.. Laboratory test results are generally non-specific and may show elevated blood levels of tumor markers like CEA. Once diagnosis has been confirmed, imaging tests like abdominal or pelvic CT scan or MRI can be used to stage the tumor by defining the location and look for lymph node involvement or metastasis, using the TNM classification.
Treatment for colorectal cancer depends on its aggressiveness and extension. For localized tumors, the treatment of choice is surgical resection of the bowel segment containing the tumor, rectal resection in cases of rectum involvement, and even complete removal of the colon, called colectomy. Also, any involved nearby lymph nodes should be resected.
In addition, many clients may require a colostomy, where the bowel contents are diverted into an artificial opening in the abdominal wall called a stoma, and ultimately eliminated into a pouch or bag. Metastasectomy or removal of metastatic cancerous tissues in other organs can also be performed.
On the other hand, for clients with unresectable metastatic tumors, as well as clients who can’t have surgery, treatment can involve a combination of chemotherapy, immunotherapy, radiation therapy, and palliative care, which can include opioid analgesics and antiemetics, in order to decrease their symptoms and improve their quality of life.
All right, let’s look at the nursing care you’ll provide for a client with colorectal cancer. The priority goals of care are to provide postoperative and colostomy care, as well as psychosocial support.
Now, if your client has had a colon resection with reanastomosis along with a colostomy, be sure to implement routine postoperative interventions, and monitor them closely for complications related to the procedure. Assist your client in a semi-Fowler position to minimize any tension on the sutures and anastomosis site. Keep them NPO, or nothing by mouth, maintain your client’s nasogastric tube, or NG tube, at low-intermittent suction; and provide the ordered IV fluids and medications.
Next, assess the colostomy site and the surrounding skin. Note normal findings, such as a pink or rosey red stoma with minimal swelling or bleeding; intact skin surrounding the stoma; and a stoma that stays well above the level of the skin with the colostomy bag securely in place;