Sigmoid Adenocarcinoma

Colorectal cancer (CRC) is the third most prevalent cancer diagnosis and the second most lethal malignancy in both men and women. Both strong environmental and genetic risk factors are found for CRC. Except for younger persons (under 50 years), the rate of new cases and death has been consistently dropping in recent years, presumably due to increased cancer screening and better treatment options. Familial Adenomatous Polyposis and Lynch syndrome are two hereditary disorders that account for about 7% of all CRC cases. For the normal colonic epithelium to transform into a precancerous lesion and, eventually, an invasive carcinoma, genetic changes must accumulate in the form of somatic (acquired) and/or germline (inherited) mutations over a 10- to 15-year period. The key mechanisms include chromosomal instability, mismatch repair, and CpG hypermethylation. The disease stage upon presentation is the most important prognostic predictor for sigmoid cancer. When evaluating prognostic and predictive chemotherapy success, all new CRC cases should be universally screened for DNA mismatch repair/microsatellite status, as well as RAS/BRAF mutational testing. A diagnostic or screening colonoscopy is required in virtually all individuals for tissue biopsy pathological confirmation of sigmoid cancer. The preferred cost-effective colon-cancer staging studies done before surgical removal are baseline computed tomography (CT) of the chest, abdomen, and pelvis with contrast and carcinoembryonic antigen (CEA). For local early-stage sigmoid cancer, surgical removal is the most common treatment option. Adjuvant therapy may improve the chances of a cure in high-risk patients with sigmoid cancer. Patients with oligometastatic, liver and lung, and local-recurrence colon cancer may be cured with multimodality therapy. Palliative systemic therapy is designated for those with non-surgical sigmoid cancer who want to improve their quality of life and live longer.

Sigmoid Adenocarcinoma Epidemiology

Colon cancer was diagnosed in more than 102,000 people in the United States in 2012, making it the fourth most frequent malignancy in both men and women. Colon cancer affects about 6% of Americans at a certain point in their lives. Colon cancer is frequently prevented, highly treated, and curative. Despite this, colon cancer is the second biggest cause of cancer-related deaths in the United States, killing over 55,000 people each year. The most common treatment is surgery. The prognosis of a patient is directly proportional to cancer's stage (how advanced it is). The pathology report received following surgical resection and biopsy of malignant tissue is the most reliable way to determine the cancer stage. The earlier colon cancer is detected and managed, the better the prognosis. The recurrence of malignant tissue after surgery is a major problem, and it is frequently the cause of mortality.

Sigmoid Adenocarcinoma Causes

In the pathogenesis of colon cancer, both hereditary and environmental factors play a role. A large percentage of colon cancers are sporadic, with 75% of patients having no family history of the disease. The typical lifetime risk of colon cancer in most Western populations is in the range of 4-5%. However, if a first-degree relative has colon cancer and was diagnosed between the ages of 50 and 70, the risk nearly doubles; if the first-degree relative was under 50 at the time of diagnosis, the risk is threefold. Individuals with two or more affected family members are at an even higher risk. As a result, in 18–20 percent of patients with colon cancer, positive family history plays a role.

Hereditary Factors

Patients with hereditary colon cancer syndrome make up a distinct subgroup of the patient population, accounting for 7-10% of all patients. Lynch syndrome is the most frequent syndrome in this group. A mutation in one of the DNA mismatch-repair genes, such as MLH1, MSH2, MSH6, PMS2, or EPCAM, causes this disease. Impaired mismatch correction during replication causes DNA mutations to accumulate, which can be seen in microsatellite DNA fragments with a repeated nucleotide sequence. The polymerase chain reaction (PCR) test, which analyzes normal and tumor DNA from the same patient, can detect this microsatellite instability (MSI). Clinical and pathological criteria, such as the Amsterdam and Bethesda criteria, were once employed to identify patients with Lynch syndrome. However, clinical experience is evolving toward unrestricted MSI PCR and immunohistochemical testing of tumor samples from all patients diagnosed before the age of 70 years for lack of expression of particular mismatch-repair proteins.

Familial adenomatous polyposis is the second most frequent hereditary colorectal cancer syndrome. Mutations in the adenomatous polyposis coli (APC) gene, which regulates the Wnt signaling pathway, cause this condition. The majority of patients with familial adenomatous polyposis acquire a substantial number of colorectal adenomatous polyps and, eventually, colon cancer, when they are young. Polyposis caused by mutations in the mutY DNA glycosylase (MUTYH) gene, Peutz Jeghers syndrome, serrated polyposis, and juvenile polyposis are other hereditary colon cancer syndromes.

Inflammatory Bowel Disease

Inflammatory bowel disease (IBD)-related chronic colitis is linked to a higher risk of colon cancer. The chance of developing IBD increases as the disease progresses. In western countries, IBD accounts for only 1.5% of colon malignancies, and several studies suggest that the incidence of colon cancer in persons with ulcerative colitis is declining as a result of efficient anti-inflammatory medications and enhanced surveillance, however, this finding is not yet universal.

Environmental Factors

Colon cancer risk is influenced by a variety of environmental, and largely controllable, lifestyle variables. Smoking, alcohol consumption, and a rise in bodyweight all raise the risk. The risk of colon cancer rises by 2-3 percent for every unit increase in body mass index. Patients with type 2 diabetes mellitus have a higher risk of colon cancer. Moderate alcohol drinking (2-3 units a day) has been linked to a 22 percent increase in the risk, whereas heavier alcohol consumption has been linked to a 55 percent increase in the risk. Smoking for long periods has a similar effect. Consumption of red and processed meat increases the risk of colon cancer by 1.2 times per 100 g of daily intake. Milk, whole grains, fresh fruits and vegetables, as well as calcium, fibers, multivitamins, and vitamin D intake, on the other hand, reduce the risk. Every 10 grams of fiber, 300 milligrams of calcium, or 200 milliliters of milk consumed daily reduces risk by about 10%. 30 minutes of daily physical activity provides a similar level of benefit. The use of low-dose aspirin has also been linked to a lower incidence of colon cancer.

Sigmoid Adenocarcinoma Symptoms

The majority of sigmoid cancer patients will be diagnosed after a diagnostic colonoscopy for worrisome signs and symptoms, asymptomatic screening, or an incidental detection during an acute abdominal urgent hospitalization. People who are diagnosed with routine cancer screening are often in a better stage than those diagnosed with advanced disease as a result of accidental surgical findings. Blood in the rectum, abdominal pain, and anemia are all indications of a diagnostic colonoscopy. Obstruction, peritonitis, and perforation are the most prevalent indications for emergency surgery. On clinical presentation, tumors can be divided into two groups: left-sided tumors with more changes in bowel movements and hematochezia, and right-sided tumors with hidden anemia impacting advanced stage at diagnosis. The symptoms at the organ affected by the route of spread will determine the late presentation with metastatic disease at diagnosis; to the liver via the portal system, to the lungs via the inferior vena cava, to supraclavicular lymphadenopathy via lymphatic, or neighboring structures by contiguous invasion. A complete physical examination should be performed to look for evidence of ascites, hepatomegaly, and lymphadenopathy. Thorough family history is essential for identifying familial clusters and inherent patterns that might affect high-risk patient surveillance and management.

Sigmoid Adenocarcinoma Diagnosis

Initial testing may include a barium enema or CT colonography, but tissue biopsy will necessitate a colonoscopy. Colonoscopy sensitivity is at 95 percent, and it can miss anywhere from 3% to 6% of cases, primarily on the right side, depending on the quality of the preparation and hands-on experience. Although flexible sigmoidoscopy is not a substitute for a full diagnostic colonoscopy, it is a screening method that lowers CRC death. PILLCAM 2 was approved by the Food and Drug Administration (FDA) for non-obstructed patients with an inconclusive colonoscopy, not for routine screening. Complete blood count, iron tests, a basic metabolic profile, a liver function test, and coagulation studies are all routine laboratory investigations that aren't diagnostic but can be helpful. When CEA levels are more than 5 ng/mL, they have a poor prognostic value, although they have low diagnostic sensitivity (45%) and specificity (90%). All recently diagnosed colon cancer patients should have a preoperative CEA, with normalization predicted following surgical removal and serial assays evaluated at follow-up visits.

The recommended cost-effective staging imaging examination before colon cancer surgical resection is a baseline CT of the chest, abdomen, and pelvis with IV and oral contrast. CT of the abdomen and pelvis provides a somewhat excellent initial evaluation for appropriately staging T and N, although it has a higher sensitivity for distant metastases right away. The use of a CT chest scan is controversial, as 9 percent of the time it will reveal equivocal lesions, with 12 percent of them being metastatic nodules. The detection of liver metastases has improved because of MRI and CT triple-phase scanning. The use of positron emission tomography (PET) for preoperative colon cancer staging is not recommended. To confirm the diagnosis, a biopsy of the worrisome metastatic location should be conducted.

Sigmoid Adenocarcinoma Staging

Consider the colon as a tube shape with five layers: the mucosa on the inside, the submucosa after, a second layer called submucosa, a third muscular layer (named the muscularis propria), and the outermost layers (named the subserosa and serosa).

Sigmoid Adenocarcinoma Stage 0

Stage 0 colon cancer, commonly known as carcinoma in situ, is the earliest stage of the disease (carcinoma refers to cancer and in situ means original position or location). Carcinoma in stage 0 has not progressed beyond the mucosa.

Sigmoid Adenocarcinoma Stage 1

The tumor has progressed through the mucosa into the submucosa or the muscularis propria in stage 1 colon cancer.

Sigmoid Adenocarcinoma Stage 2

One of the following things describes stage 2 colon cancer:

Cancer has spread to the colon's outer layers, but not through them.
Cancer has spread to the outer layer of the colon, but not to other tissues or organs nearby.
Cancer has spread through the colon's wall and has adhered to or expanded into other tissues or organs around.
Through the mucosa, cancer has spread to the submucosa and probably the muscularis propria.

Sigmoid Adenocarcinoma Stage 3

Colon cancer in stage 3 can imply one of several things:

Cancer has spread to four to six neighboring lymph nodes after growing into the submucosa layer.
Cancer has spread to one to three surrounding lymph nodes or fat regions near the lymph nodes after growing through the colon's outermost layers.
Cancer has spread to four to six neighboring lymph nodes after growing into the muscularis propria, or outermost layer of the colon.
Cancer has progressed to seven or more surrounding lymph nodes and has progressed into the submucosa and potentially into the muscularis propria.
Cancer has spread to four to six neighboring lymph nodes after growing through the colonic wall.
Cancer has progressed to seven or more neighboring lymph nodes and has expanded into the colon's outer layers.
Cancer has progressed to at least one neighboring lymph node or into regions of fat around the lymph node, is adhered to or has spread into adjacent tissues or organs, and has grown through the colon wall.

Sigmoid Adenocarcinoma Stage 4

Stage four colon cancer can be described in a variety of ways, just like stage 2 and 3 cancer. Stage 4 colon cancer is the same as metastatic colon cancer, which has migrated to one or more distant organs (such as the liver or lungs), a distal set of lymph nodes, or distant portions of the abdominal cavity lining (called the peritoneum).

Dealing with a stage 4 cancer diagnosis can be a mentally and physically draining experience. Although stage 4 colon cancer is not curable for the majority of people, there are usually treatments available.

Sigmoid Adenocarcinoma Treatment

Surgical resection is the primary therapeutic option for localized non-metastatic stage colon cancer in patients of any age who have a good functioning status and manageable comorbidities. Endoscopic resection (ER) is reserved for colon carcinomas discovered in low-risk polyps and early-stage (cT0-1). Neoadjuvant treatment is not standard of care for colon cancer and is only used when surgical conversion is necessary due to severe disease. All colon cancer stage III (node-positive) patients should get adjuvant therapy, which is tailored to the stage II patient with high-risk characteristics. On oligometastatic lung and liver disease, surgery combined with peri-chemotherapy may provide a curative approach. Non-surgical patients with unresectable locally advanced cancer or a significant metastatic burden are provided palliative systemic chemotherapy, which improves the quality of life and extends the average lifespan. Patients with localized recurrent diseases who are treated individually may be cured with multimodality treatment.

Endoscopic Resection

Endoscopic local excisions should achieve total tumor removal and surrounding tissue resection in a single block. Patients who consent to close, aggressive surveillance afterward, a surgical removal for high-risk disease, and/or non-surgical candidates should go to the ER. A skilled surgeon at a center of excellence will offer ER procedures. High-risk features (which need further surgical resection) include invasion of the muscularis propria (T2), poor histological grade, LVI, PNI, at the stalk, or flat/depressed sessile polyp. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are two methods for removing colon cancer polyps that have a high success rate of 90% and a low recurrence rate of 14 percent, with invasive cancer occurring in 0.5 percent of favorable risk individuals. Perforation and hemorrhage are the most common complications, accounting for 7 percent and 2 percent of cases, respectively, with an exceedingly low mortality rate of 1 percent. All lesions should be tattooed, regardless of the technique, to enable site identification during subsequent steps.

Surgical Resection

For all stages of colon cancer, surgical resection (removal of cancer in an operation) is the most standard treatment. A doctor may perform one of the following surgeries to treat cancer:

Local excision. If the cancer is discovered at an early stage, the doctor may be able to remove it without penetrating through the abdominal wall. Instead, the doctor may insert a tube into the colon with a cutting tool and cut out the tumor. A polypectomy is performed when cancer is discovered in a polyp (a tiny bulging mass of tissue).
Colon resection with anastomosis. If the malignancy is more advanced, the doctor will conduct a partial colectomy with anastomosis (removing the tumor and a small amount of healthy tissue around it). After that, the doctor may make an anastomosis (connecting the healthy parts of the colon). In most cases, the doctor will also remove lymph nodes surrounding the colon and check them under a microscope for malignancy.
Colon resection with colostomy. If the doctor is unable to suture the two ends of the colon back together, a stoma (an outlet) on the outside of the body is created for waste to pass through. A colostomy is a medical term for this surgery. To collect waste, a bag is inserted around the stoma. The colostomy may only be required until the lower colon has recovered, after which it can be removed. The colostomy may be lifelong if the doctor needs to remove the entire colon.

Some patients may be given chemotherapy or radiotherapy following surgery to destroy any cancer cells that remain after the doctor removes any malignancy that can be seen at the time of surgery. Adjuvant therapy is a treatment provided after surgery to reduce the chances of cancer recurring.

Sigmoid Adenocarcinoma Prognosis

Colon cancer was diagnosed in more than 102,000 people in the United States in 2012, making it the fourth most frequent malignancy in both men and women. Colon cancer affects about 6% of Americans at a certain point in their lives. Colon cancer is frequently prevented, highly treated, and curative. Despite this, colon cancer is the second biggest cause of cancer-related deaths in the United States, killing over 55,000 people each year. The most common treatment is surgery. The prognosis of a patient is directly proportional to cancer's stage (how advanced it is). The pathology report received following surgical resection and biopsy of malignant tissue is the most reliable way to determine the cancer stage. The earlier colon cancer is detected and managed, the better the prognosis. The frequency of upcoming exams is determined by the previous exam's outcomes.

Conclusion

Colon cancer is prevalent cancer that kills a large number of people. However, if detected early enough, it is possibly avoidable by screening and highly treatable with surgery alone. For patients with more advanced stages of cancer, modern chemotherapy continues to enhance survivability. Because the symptoms of colon cancer are so nonspecific, they must be evaluated by a medical specialist. Colorectal surgeons, medical oncologists, radiologists, and pathologists are commonly part of a team of experts treating colon cancer. These physicians collaborate with the patient to provide the safest and most successful treatment plan possible.