Endoscopy

What it is

Endoscopy is a procedure that uses a flexible tube with a camera to look inside the body and often take biopsies or treat problems, and a typical endoscopy may take about 10 minutes to 1 hour depending on the type and whether treatment is done. The tube is called an endoscope. It is usually passed through a natural opening such as the mouth, anus, urethra, or vagina, though some endoscopic procedures use a small cut in the skin. In cancer care, endoscopy is important because it can help find the cause of symptoms, detect suspicious growths, collect tissue for biopsy, and sometimes treat bleeding or remove small lesions during the same session.

For digestive diseases, the term often refers to upper gastrointestinal endoscopy, also called oesophagogastroduodenoscopy or EGD, which examines the oesophagus, stomach, and duodenum. But endoscopy is a broader category that includes several procedures used in different organs.

Common type	Area examined	Usual purpose
Upper GI endoscopy (EGD, gastroscopy)	Oesophagus, stomach, duodenum	Evaluate pain, reflux, bleeding, swallowing problems, ulcers, tumours
Colonoscopy	Colon and rectum	Look for bleeding, polyps, inflammation, cancer
Sigmoidoscopy	Lower colon	Assess bleeding, bowel symptoms, inflammation
Bronchoscopy	Airways and lungs	Check cough, bleeding, infection, tumours
Cystoscopy	Bladder and urethra	Evaluate blood in urine, bladder lesions
Hysteroscopy	Uterus	Assess abnormal bleeding, polyps, fibroids

In India, endoscopy is widely used in gastroenterology, pulmonology, urology, and gynecology at tertiary hospitals and many day-care centres. The exact preparation and recovery advice depend on the organ being examined and whether sedation is planned.

How it works

An endoscope has a light source and camera that send images to a screen so the clinician can inspect the lining of an organ in real time. Many endoscopes also have channels through which small tools can be passed. These tools can be used to take a biopsy, stop bleeding, remove a foreign body, widen a narrowed area, or remove some polyps.

During an upper endoscopy, the scope is passed through the mouth and throat into the upper digestive tract. During colonoscopy, it is passed through the anus into the large intestine. Air or carbon dioxide may be introduced to open the area slightly and improve visibility. Some centres also use enhanced imaging methods, such as high-definition imaging or narrow band imaging, to help identify abnormal or precancerous tissue more clearly.

Sedation varies. Some endoscopies are done with only local anesthetic spray or gel, while others use intravenous sedatives. More complex procedures may require deeper sedation or anesthesia. If sedation is used, patients usually need monitoring during and after the procedure and should not drive for 24 hours.

Evidence and uses

Endoscopy is an established, standard medical procedure with both diagnostic and therapeutic roles. It is commonly used when symptoms suggest disease inside a hollow organ or when imaging alone cannot provide enough detail. In cancer evaluation, one of its main strengths is that it allows direct visualisation plus biopsy, which is often necessary to confirm a diagnosis.

Common reasons for endoscopy include:

1. Investigating symptoms such as difficulty swallowing, persistent indigestion, abdominal pain, vomiting, gastrointestinal bleeding, blood in stool, chronic diarrhoea, or unexplained anaemia.
2. Diagnosing conditions such as ulcers, inflammation, polyps, strictures, Barrett's oesophagus, inflammatory bowel disease, and cancers.
3. Taking tissue samples for pathology, microbiology, or molecular testing.
4. Treating problems during the same procedure, such as stopping bleeding, removing some polyps, extracting foreign bodies, or placing stents.

For suspected gastrointestinal cancers, endoscopy is often the first-line procedure because it can directly inspect the lesion and obtain tissue. For example, upper GI endoscopy is central in evaluating suspected oesophageal or stomach cancer, while colonoscopy is central for colorectal lesions. Endoscopic ultrasound, a related technique, can help assess the depth of a tumour and nearby lymph nodes in some cancers.

That said, endoscopy is not perfect. A normal endoscopy does not rule out every disease, and some lesions can be missed, especially if bowel preparation is poor, visibility is limited, or the abnormality is very small or flat. The quality of the examination, the indication, and the operator's expertise all affect accuracy.

Diagnosis / how it's measured

Endoscopy itself is a diagnostic procedure rather than a lab test, so there is no single number that defines a normal or abnormal result. The findings are based on what the clinician sees and whether biopsies show disease under the microscope.

A typical endoscopy report may include:

• The area examined and whether the exam was complete
• Visible findings such as inflammation, ulcers, bleeding, polyps, masses, narrowing, or normal mucosa
• Whether biopsies or treatments were performed
• Immediate complications, if any
• A preliminary impression and follow-up plan

Biopsy results are often the most important part when cancer is suspected. A visible lesion may suggest cancer, but pathology is usually needed to confirm the diagnosis and identify the tumour type. Patients should ask for both the procedure report and the pathology report, since they answer different questions.

Preparation also affects diagnostic quality. For upper endoscopy, fasting for several hours is usually required. For colonoscopy, bowel cleansing is essential; poor preparation can reduce the ability to detect polyps or cancers and may mean the test needs to be repeated.

When to see a clinician

A clinician may recommend endoscopy if you have alarm symptoms or persistent unexplained symptoms. Seek medical advice promptly for vomiting blood, black stools, blood in stool, trouble swallowing, unexplained weight loss, persistent vomiting, severe anaemia, or ongoing abdominal pain.

In cancer care, endoscopy may also be advised after an abnormal scan, positive stool test, suspicious biopsy from another site, or to monitor known conditions that can raise cancer risk. If you are scheduled for endoscopy, tell the team about blood thinners, diabetes medicines, allergies, heart or lung disease, pregnancy, implanted devices, and any previous reaction to sedation.

Limitations and open questions

Endoscopy is very useful, but it has limits. It mainly shows the inner lining of organs, so disease deeper in the wall or outside the organ may need ultrasound, CT, MRI, or endoscopic ultrasound for better assessment. Some procedures can miss subtle lesions, and biopsy samples may occasionally be nondiagnostic, requiring repeat testing.

Risks are usually low but can include bleeding, infection, reaction to sedation, and perforation, which is a tear in the organ wall. The risk depends on the type of endoscopy and whether treatment is done during the procedure. Therapeutic procedures generally carry more risk than a simple diagnostic examination.

Newer imaging methods, artificial intelligence-assisted detection, and advanced therapeutic endoscopy are improving what can be found and treated without surgery. Even so, outcomes still depend on good preparation, appropriate indications, careful technique, and expert interpretation. If the reason for your endoscopy, the expected benefit, or the follow-up plan is unclear, ask your clinician to explain what the test is looking for and how the result will change treatment.