Overview
Gastrointestinal (GI) cancers encompass malignancies that develop in the organs of the digestive system, including the esophagus, stomach, small intestine, colon, rectum, liver, gallbladder, and pancreas. Among these, colorectal cancer is the third most commonly diagnosed cancer and the second leading cause of cancer-related death in the United States. However, colorectal cancer is also one of the most preventable cancers through regular screening, and when detected early, it is highly treatable with a five-year survival rate exceeding 90% for localized disease.
Dr. Khan is committed to cancer prevention through screening colonoscopy, surveillance of high-risk patients, and early detection of precancerous and cancerous lesions throughout the GI tract.
Colorectal Cancer
What Is Colorectal Cancer?
Colorectal cancer develops when cells in the colon or rectum grow uncontrollably. Most colorectal cancers begin as precancerous growths called polyps on the inner lining of the colon or rectum. Over time — typically 10 to 15 years — certain types of polyps (adenomatous polyps and sessile serrated polyps) can transform into cancer. This slow progression from polyp to cancer provides a critical window for prevention: removing polyps during a colonoscopy can prevent cancer from ever developing.
Symptoms
Colorectal cancer often causes no symptoms in its early stages, which is why screening is so important. When symptoms do appear, they may include:
- Change in bowel habits: Persistent diarrhea, constipation, or narrowing of the stool lasting more than a few days
- Rectal bleeding or blood in the stool: Bright red blood or dark, tarry stools
- Abdominal discomfort: Persistent cramps, gas, pain, or a feeling of fullness
- Feeling that the bowel does not empty completely
- Unexplained weight loss
- Fatigue and weakness: Often due to iron deficiency anemia from chronic occult blood loss
Risk Factors
- Age: Risk increases with age; the recommended screening starting age is now 45 for average-risk individuals (updated from 50 by the American Cancer Society and USPSTF)
- Family history: Having a first-degree relative (parent, sibling, or child) with colorectal cancer or advanced adenomas doubles your risk. Screening should begin 10 years before the age at which the youngest affected relative was diagnosed, or at age 40, whichever is earlier
- Personal history of polyps or colorectal cancer
- Inflammatory bowel disease: Long-standing ulcerative colitis or Crohn's colitis increases risk
- Hereditary syndromes: Lynch syndrome (hereditary nonpolyposis colorectal cancer or HNPCC) and familial adenomatous polyposis (FAP) carry substantially elevated risk
- Lifestyle factors: Sedentary lifestyle, obesity, high consumption of red and processed meats, low fiber intake, heavy alcohol use, and smoking
- Type 2 diabetes: Associated with increased colorectal cancer risk
- Race and ethnicity: African Americans have the highest incidence and mortality rates and may benefit from screening beginning at age 40
Rising Rates in Young Adults
There has been an alarming increase in colorectal cancer diagnoses in adults under 50, with rates approximately doubling since the 1990s. While the reasons are not fully understood, factors such as obesity, sedentary lifestyles, dietary changes, and alterations in the gut microbiome are under investigation. This trend underscores the importance of the updated screening guidelines recommending colonoscopy starting at age 45, and the need for young adults to take GI symptoms seriously and seek evaluation promptly.
Screening and Prevention
Screening is the most powerful tool in the fight against colorectal cancer. Dr. Khan performs screening colonoscopies and recommends screening intervals based on individual risk:
Colonoscopy (Gold Standard)
Colonoscopy is the preferred screening method because it allows direct visualization of the entire colon, detection of polyps and cancers, and immediate removal of precancerous polyps during the same procedure. For average-risk patients with a normal result, repeat colonoscopy is recommended every 10 years. If polyps are found, follow-up intervals are shorter (typically 3 to 5 years) depending on the number, size, and type of polyps.
Other Screening Options
For patients who are unable or unwilling to undergo colonoscopy, alternative screening methods include:
- Fecal immunochemical test (FIT): An annual stool test that detects hidden blood in the stool
- Multi-target stool DNA test (Cologuard): A stool test that detects both blood and abnormal DNA shed by polyps and cancers, recommended every 3 years
- CT colonography (virtual colonoscopy): A CT scan of the colon, recommended every 5 years
It is important to note that a positive result on any of these alternative tests requires a follow-up colonoscopy for definitive evaluation.
Other GI Cancers
Esophageal Cancer
The two main types are squamous cell carcinoma (associated with smoking and alcohol) and adenocarcinoma (associated with chronic GERD and Barrett's esophagus). Symptoms include progressive difficulty swallowing, unintentional weight loss, chest pain, and chronic cough. Patients with Barrett's esophagus require regular surveillance endoscopy to detect dysplasia early.
Stomach (Gastric) Cancer
Risk factors include Helicobacter pylori infection (the leading risk factor), smoking, a diet high in smoked or salted foods, family history, and pernicious anemia. Symptoms often appear late and include unintentional weight loss, persistent abdominal pain, nausea, early satiety, and GI bleeding.
Pancreatic Cancer
Pancreatic cancer carries a poor prognosis largely because it is typically diagnosed at an advanced stage. Risk factors include smoking, obesity, chronic pancreatitis, diabetes, family history, and certain genetic syndromes (BRCA2, Lynch syndrome). Symptoms include painless jaundice, new-onset diabetes, unexplained weight loss, deep abdominal pain radiating to the back, and loss of appetite.
Liver Cancer (Hepatocellular Carcinoma)
Hepatocellular carcinoma (HCC) most commonly develops in the setting of chronic liver disease and cirrhosis. Major risk factors include chronic hepatitis B, chronic hepatitis C, alcohol-related liver disease, and MASLD/MASH-related cirrhosis. Patients with cirrhosis from any cause require surveillance with liver ultrasound and alpha-fetoprotein (AFP) testing every 6 months.
Diagnosis
Dr. Khan utilizes multiple diagnostic tools for evaluating GI cancers:
- Colonoscopy with polypectomy and biopsy: For detecting and removing colorectal polyps and obtaining tissue for pathological evaluation
- Upper endoscopy (EGD) with biopsy: For evaluating esophageal and gastric lesions
- Endoscopic ultrasound (EUS): For staging GI cancers and evaluating pancreatic masses
- Capsule endoscopy: For detecting small bowel tumors
- Cross-sectional imaging: CT, MRI, and PET scans for staging and surveillance
- Blood tests: Tumor markers (CEA for colorectal cancer, AFP for liver cancer, CA 19-9 for pancreatic cancer) and genetic testing for hereditary cancer syndromes
Treatment Options
Treatment for GI cancers depends on the type, stage, and location of the cancer, as well as the patient's overall health. Dr. Khan works closely with oncologists, surgeons, and radiation oncologists as part of a multidisciplinary team. Options may include:
- Endoscopic resection: For early-stage cancers and large polyps (endoscopic mucosal resection or endoscopic submucosal dissection)
- Surgery: Resection of the affected segment of the GI tract
- Chemotherapy: Systemic treatment to destroy cancer cells
- Radiation therapy: Particularly for rectal cancer, often combined with chemotherapy
- Targeted therapy and immunotherapy: Newer treatments that target specific molecular pathways or harness the immune system to fight cancer
When to See a Doctor
You should consult a gastroenterologist if you:
- Are 45 or older and have not had a screening colonoscopy
- Have a family history of colorectal cancer or polyps and have not discussed a screening plan
- Notice blood in your stool or on toilet paper
- Experience a persistent change in bowel habits
- Have unexplained weight loss, fatigue, or iron deficiency anemia
- Experience progressive difficulty swallowing
- Develop new-onset jaundice or persistent abdominal pain
- Have a personal history of inflammatory bowel disease, Barrett's esophagus, or hereditary cancer syndromes
- Have chronic hepatitis B or cirrhosis from any cause and need cancer surveillance
Dr. Amber Khan at GastroCares is passionate about colorectal cancer prevention and early detection. Through screening colonoscopy and evidence-based surveillance programs, she helps patients reduce their cancer risk and detect problems at the earliest, most treatable stage. Do not delay your screening — it could save your life.