Understanding Gastrointestinal Cancer: Signs, Types & Early Detection

When you experience persistent symptoms like abdominal pain, unexplained weight loss or changes in digestion, it is natural to feel a sense of worry. The digestive system is complex, and while many issues are benign, these symptoms can sometimes indicate a more serious condition. When these signs lead to a diagnosis of gastrointestinal (GI) cancer, the clock starts ticking.

Navigating the possibility of a cancer diagnosis is overwhelming, but knowledge is your most powerful tool. Understanding the signs of gastrointestinal cancer, the specific types that affect the digestive tract, and the importance of early detection can dramatically change the course of treatment and outcomes.

At Franciscan Health, we understand that GI cancers are some of the most challenging malignancies in modern medicine. However, with advances in screening and a coordinated approach to care, patients have more hope than ever before. This guide will walk you through the complexities of GI cancer, helping you recognize when to seek help and understanding the care pathway available to you in Indiana.

Key Takeaways: Gastrointestinal Cancers

• Gastrointestinal cancers are a group of cancers that impact the digestive tract and related organs. Colorectal, pancreatic, liver, stomach and esophageal cancers are among the most common GI cancers.
• A change in bowel habits, abdominal pain, blood in the stool, anemia and unplanned weight loss are signs of possible gastrointestinal cancers.
• Early detection through screening can dramatically improve treatment outcomes.
• Adults age 45 and older should discuss colorectal cancer screening with their provider.

What Is Gastrointestinal Cancer?

Gastrointestinal cancer is not a single disease but a diverse group of cancers that affect the digestive tract and its related organs. The digestive system is a long, winding pathway that processes food, absorbs nutrients and eliminates waste from your body. It includes the esophagus, stomach, small intestine, colon, rectum, liver, pancreas and gallbladder.

Gastrointestinal cancers can develop when cells in these organs begin to grow uncontrollably, forming a tumor. These malignant cells can invade nearby tissues and, over time, spread to other parts of the body. Because the digestive tract is so extensive, the symptoms and treatments vary significantly depending on where the cancer originates.

According to Thayer Nasereddin, MD, a gastroenterologist and interventional endoscopist at Franciscan Health Indianapolis, the most frequently encountered GI cancers include:

• Colorectal cancer
• Liver cancer
• Pancreatic cancer
• Gastric (stomach) cancer
• Esophageal cancer
• Bowel cancer.

These GI cancers present unique challenges in diagnosis and management, but they all share one common truth: Early detection is the single most important factor in improving survival rates.

What Are Early Signs Of Gastrointestinal Cancer?

One of the greatest challenges with GI cancers is that they often develop silently. In the early stages, a tumor may be too small to cause noticeable discomfort. As the disease progresses, symptoms may appear, but these signs are often vague and easily mistaken for less serious conditions such as indigestion, ulcers, or a viral infection.

However, there are specific warning signs that should never be ignored. Identifying these signs and sharing them with your primary care provider is the first step toward diagnosis.

“The red flags are fairly consistent: unexplained gastrointestinal bleeding, unexplained iron deficiency anemia, significant weight loss, or persistent abdominal pain,” Dr. Nasereddin said. “If you see these, don’t wait."

Unexplained weight loss

Losing weight without trying—such as through diet, medication or increased exercise—is a significant alarm bell.

Cancer cells consume a large amount of the body's energy supply, which can lead to weight loss. Additionally, in the case of GI cancers, a tumor may physically block the absorption of nutrients or cause a feeling of fullness that prevents you from eating enough.

If you lose 10 pounds or more without a clear reason, it is time to consult a doctor.

Gastrointestinal bleeding and anemia

Blood in the stool is a primary sign of gastrointestinal cancer, particularly colorectal cancer. The blood may appear bright red, or it may make the stool look very dark or tarry (melena), indicating bleeding higher up in the digestive tract, such as in the stomach or esophagus.

Often, bleeding is microscopic and not visible to the naked eye. This chronic, slow blood loss leads to iron deficiency anemia.

"Primary care physicians are often the first to spot red flags like unexplained anemia, weight loss, or abnormal liver enzymes," Dr. Nasereddin said.

If routine blood work reveals low iron levels, it requires immediate investigation to rule out a GI source.

Persistent abdominal pain

While everyone experiences an occasional stomachache, persistent abdominal pain or discomfort is different. This might present as cramping, a dull ache, or sharp pain. It can be caused by a tumor pressing on organs, nerves or blood vessels. Pain associated with eating or pain that does not resolve with standard over-the-counter remedies warrants a closer look.

Changes in bowel habits

Your digestive habits act as a window into your GI health. Significant changes to your bowel movements that last for more than a few days are concerning. This includes:

• Chronic diarrhea or constipation.
• A change in the consistency of your stool.
• Narrowing of the stool (sometimes described as pencil-thin).
• A feeling that the bowel does not empty completely.

Difficulty swallowing (Dysphagia)

For cancers of the upper digestive tract, such as esophageal or stomach cancer, difficulty swallowing is a hallmark symptom. It may feel like food is sticking in your throat or chest. This often starts with solid foods and can progress to liquids as the tumor grows and narrows the passage.

Which Gastrointestinal Cancers Are Most Common?

Because the GI tract spans so many organs, "GI cancer" is an umbrella term. To understand your risks and symptoms, it helps to look at the specific types of cancer individually.

Colorectal cancer

Colorectal cancer starts in the colon or the rectum.

Most colorectal cancers start as a growth called a polyp on the inner lining of the colon or rectum. Over time, some polyps can turn into cancer. Colon and rectal cancers often develop silently, only becoming apparent at an advanced stage. This silent progression is why screening is so vital. By the time symptoms like rectal bleeding or abdominal pain appear, the cancer may be more advanced.

Pancreatic cancer

The pancreas releases enzymes that aid digestion and produces hormones that help manage blood sugar. Pancreatic cancer is known for being difficult to detect early because the pancreas is located deep inside the abdomen, behind the stomach.

Symptoms often do not appear until the cancer has spread to nearby organs. When they do appear, they may include jaundice (yellowing of the skin and eyes), dark urine, itchy skin, and pain in the upper abdomen that radiates to the back.

"Pancreatic and liver cancers carry very poor prognoses if they’re not caught early," Dr. Nasereddin explained.

Liver cancer

The liver is the largest internal organ, essential for filtering blood and removing toxins. Liver cancer often arises in patients with underlying health conditions.

As Dr. Nasereddin noted, liver cancer "often arises in patients with underlying cirrhosis or hepatitis, complicating management."

Symptoms of liver cancer can include:

• A hard lump on the right side just below the rib cage
• Swelling of the abdomen
• Jaundice.

Because the liver has a remarkable ability to function even when damaged, symptoms may not manifest until the disease is advanced.

Stomach (Gastric) cancer

Stomach cancer, or gastric cancer, usually begins in the mucus-producing cells that line the stomach. In the United States, stomach cancer is less common than it used to be, but it remains a serious diagnosis.

Early symptoms are often mistaken for heartburn or indigestion. A specific sign of stomach cancer is a sense of "early satiety"—feeling full after eating only a small amount of food. Other signs include severe, persistent heartburn, nausea, and vomiting, sometimes with blood.

Esophageal cancer

The esophagus is the hollow tube that carries food from your throat to your stomach. Cancer in the esophagus usually develops in the cells that line the inside of the esophagus. Aside from trouble swallowing, symptoms can include hoarseness, chronic cough, chest pain or pressure in the chest.

Who Is Most At Risk For GI Cancer?

While anyone can develop gastrointestinal cancer, certain factors can increase your likelihood of developing the disease. Understanding these risk factors can help you and your doctor decide on the right screening schedule for you.

Age and family history

The risk of most GI cancers increases as you get older. However, diagnoses in younger people are becoming more common, particularly for colorectal cancer.

Family history plays a crucial role. If a parent, sibling, or child had GI cancer, your risk is higher. Specific genetic syndromes, such as Lynch syndrome or familial adenomatous polyposis (FAP), can significantly raise the risk of developing colon and other GI cancers.

"Patients with a family history of colorectal or gastric cancer may need to start screening earlier," Dr. Nasereddin said.

Lifestyle factors

Your daily habits have a profound impact on your digestive health. Modifiable risk factors include:

• Diet: Diets high in red meats (beef, pork, lamb) and processed meats (hot dogs, luncheon meats) have been linked to colorectal cancer. Conversely, diets rich in fruits, vegetables and whole grains appear to lower risk.
• Tobacco and alcohol: Smoking is a major cause of many GI cancers, including stomach, pancreatic, and esophageal cancer. heavy alcohol use is strongly linked to liver, esophageal, and colorectal cancers.
• Weight: Being overweight increases the risk of many cancers, particularly those of the colon, rectum, pancreas and esophagus.

Underlying health conditions

Chronic inflammation in the GI tract can predispose cells to become cancerous. Conditions such as inflammatory bowel disease (ulcerative colitis and Crohn’s disease) increase the risk of colorectal cancer. Similarly, long-standing acid reflux (GERD) can damage the esophagus, leading to a precancerous condition called Barrett’s esophagus.

Symptoms often do not appear until the cancer has spread to nearby organs. When they do appear, they may include jaundice (yellowing of the skin and eyes), dark urine, itchy skin and pain in the upper abdomen that radiates to the back.

When Should You See A Doctor About Digestive Symptoms?

If there is one message to take away, it is that you should not wait for symptoms to appear before thinking about your digestive health. Screening allows doctors to find cancer before you feel it, or even prevent it entirely.

"The biggest take-home message on cancer treatment is either early detection or prevention," said Dipen Maun, MD, a colon and rectal surgeon at Franciscan Health. "That’s where primary care providers can make the biggest impact—by encouraging patients to advocate for themselves and stay current on screening guidelines."

The new standard for colorectal screening

Screening guidelines evolve as medical research advances. A significant change occurred recently regarding colorectal cancer. In 2021, the recommended age for routine colon cancer screening dropped from 50 to 45 years for average-risk adults.

This change reflects the growing number of younger adults being diagnosed with the disease. If you are 45 or older, talk to your doctor about your colon cancer screening options.

How Can You Lower Your Risk Of Gastrointestinal Cancer?

While the medical team plays a critical role, you are the most important member of your healthcare team. Empowering yourself with knowledge and practicing self-advocacy are vital steps in protecting your health.

Listen to your body

You know your body better than anyone else. If something feels wrong, trust your instincts. Symptoms like persistent indigestion, fatigue, or changes in bathroom habits are your body's way of signaling distress. It is always better to get checked and find nothing than to ignore a potential warning sign of gastrointestinal cancer.

Adopt a healthy lifestyle

While not all cancers can be prevented, you can lower your risk through healthy choices.

• Eat a balanced diet high in fiber, fruits, and vegetables.
• Limit red and processed meats.
• Maintain a healthy weight.
• Quit smoking and limit alcohol intake.
• Stay physically active.

Talk to your doctor about screenings

The journey to a diagnosis often begins in a primary care office. Your primary care doctor acts as the first line of defense, monitoring your overall health and identifying abnormalities in routine exams.

Do not wait for your doctor to bring up if it's time for you to get cancer screenings. If you are 45, ask about a colonoscopy. If you have a family history of GI cancer, ask if you should be screened sooner.

When Should I See A Doctor For Possible GI Cancer Symptoms?

See a provider if you have:

• Blood in your stool
• Unexplained weight loss
• Persistent abdominal pain
• Ongoing changes in bowel habits
• Difficulty swallowing
• Iron-deficiency anemia without a known cause

Dr. Nasereddin emphasizes urgency when red flags are present.

"The red flags are fairly consistent: unexplained gastrointestinal bleeding, unexplained iron deficiency anemia, significant weight loss, or persistent abdominal pain. If you see these, don’t wait; refer the patient to a specialist right away."

If you have concerning health symptoms on top of a family history, a referral should not be delayed. Do not downplay your symptoms. Be honest about pain levels, bowel changes, and fatigue. Early referral to a cancer specialist leads to a wider range of treatment options and better potential outcomes.

“Colorectal cancer is still one of the leading causes of cancer-related deaths in the United States,” said Dr. Nasereddin. “At the same time, pancreatic and liver cancers carry very poor prognoses if they’re not caught early. That’s why early detection and referral are so important.”

Moving Forward With Confidence

Gastrointestinal cancer is a serious diagnosis, but it is one that modern medicine is increasingly equipped to handle. From the advanced diagnostic capabilities of interventional endoscopy to the precision of modern surgical techniques, the landscape of GI cancer care is constantly improving.

By understanding the signs of gastrointestinal cancer—those consistent red flags of bleeding, weight loss, and pain—you take the first step toward protection. By adhering to screening guidelines, you open the door to prevention. And by relying on a collaborative team of specialists like those at Franciscan Health, you ensure that if a diagnosis occurs, you have the expertise and support necessary to navigate the journey ahead.

"GI cancers are complex, but patients don’t have to face them alone," Dr. Maun said. "With the right collaboration between primary care and specialists, we can guide patients through every step of treatment and give them the best possible chance."

If you are experiencing persistent digestive symptoms, have a family history of GI cancer or are due for colorectal cancer screening, the specialists at Franciscan Health can help. Our gastroenterologists, primary care providers and cancer specialists work together to identify concerns early and create personalized treatment plans.

Find a Franciscan Health provider or schedule an appointment today.