STER (Submucosal Tunneling Endoscopic Resection)
STER is an advanced minimally invasive endoscopic procedure used to remove tumors growing beneath the inner lining of the digestive tract, mainly in the esophagus and stomach. It is commonly performed by advanced gastroenterologists using a flexible endoscope passed through the mouth, without external cuts or surgery.
What is STER?
STER stands for:
Submucosal Tunneling Endoscopic Resection
In this procedure:
- A small opening is created in the inner lining (mucosa)
- A tunnel is made beneath the lining
- The tumor is identified and removed from the muscle layer
- The entry site is closed with clips
The technique is similar to the tunneling method used in POEM procedure for achalasia.
Which Tumors are Treated with STER?
STER is mainly used for subepithelial or submucosal tumors arising from the muscular layer of GI tract.
Common lesions include:
- Gastrointestinal stromal tumors (GIST)
- Leiomyoma
- Neuroendocrine tumors
- Small benign muscular tumors
- Certain diagnostic submucosal masses
Usually ideal for tumors:
- Less than 3–3.5 cm
- Covered by intact mucosa
-
Located in:
- Esophagus
- Gastroesophageal junction
- Upper stomach/cardia
Why is STER Done?
Indications
STER may be advised when:
- Tumor is increasing in size
- Patient has difficulty swallowing
- Bleeding from lesion
- Chest pain or upper abdominal discomfort
- Suspicion of cancerous potential
- Need for definitive biopsy/removal
- To avoid open surgery
Advantages of STER
Benefits
- No external surgical cuts
- Organ-preserving procedure
- Faster recovery
- Less pain
- Short hospital stay
- Lower complication rate than surgery
- Better cosmetic outcome
- Faster return to normal diet/work
Studies show high complete tumor removal rates with good safety profile.
Pre-Procedure Evaluation
Before STER, patient may require:
- CBC
- PT/INR
- Liver & kidney function tests
- ECG
- Chest imaging if needed
- Endoscopy
- CT scan
- EUS (Endoscopic Ultrasound)
Fasting
Usually:
- Nil by mouth for 6–8 hours before procedure
Medication Advice
Blood thinners may need temporary stoppage after doctor advice.
How is STER Performed?
Step-by-Step Procedure
- General anesthesia is given
- Endoscope inserted through mouth
- Injection given beneath mucosa
- Small mucosal incision made
- Submucosal tunnel created
- Tumor identified
- Tumor dissected from muscle layer
- Tumor removed
- Tunnel opening closed using clips
Procedure Duration
Usually:
- 1–3 hours depending on tumor size/location
Is STER Painful?
No.
- Procedure is done under anesthesia
- Patient remains asleep
- Mild throat pain or chest discomfort can occur later
Hospital Stay
Usually:
- 1–4 days depending on recovery and complications
Diet After STER
Common protocol:
- Initial fasting
- Liquid diet
- Soft diet
- Gradual normal diet over 1–2 weeks
PPIs and antibiotics are commonly prescribed temporarily.
Recovery Time
Most patients:
- Resume light activity in few days
- Return to routine work within 1–2 weeks
Possible Complications
Although generally safe, complications may include:
- Bleeding
- Perforation
- Infection
- Pneumothorax (air leak around lungs)
- Pneumomediastinum
- Fever
- Mucosal injury
- Incomplete tumor removal
Large tumors and difficult locations carry higher risks.
When to Contact Doctor After STER?
Seek urgent medical attention if:
- Severe chest pain
- Difficulty breathing
- Vomiting blood
- Fever
- Severe abdominal pain
- Black stools
- Persistent vomiting
Success Rate
STER has:
- High en-bloc resection rate
- Good long-term outcomes
- Lower morbidity than surgery in selected patients
Especially effective for small to medium tumors.
Follow-Up After STER
Follow-up may include:
- Repeat endoscopy
- Histopathology review
- CT or EUS if needed
- Monitoring for recurrence
Tumor biopsy result determines if further treatment is required.
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