How should a gastric mass be evaluated and managed in a patient who is in the first trimester of pregnancy?

Management of Gastric Mass in First Trimester Pregnancy

If the gastric mass poses a significant risk to maternal health or causes concerning symptoms (bleeding, obstruction, severe anemia), proceed with upper endoscopy immediately—even in the first trimester—as maternal health takes priority; however, if the mass is incidentally discovered and the patient is asymptomatic, defer endoscopic evaluation until the second trimester to minimize fetal risk. 1

Risk Stratification and Timing

The 2024 AGA guidelines establish a clear framework for endoscopy timing in pregnancy 1:

• Emergent indications (active bleeding, severe anemia, obstruction): Perform endoscopy at any gestational age
• Non-urgent but necessary procedures: Postpone until after the first trimester, ideally second trimester
• Elective procedures: Defer until postpartum period

Red Flag Symptoms Requiring Immediate Evaluation

Look specifically for:

• Melena or hematemesis (as seen in reported GIST cases) 2
• Severe anemia (hemoglobin <70 g/L)
• Persistent vomiting beyond typical hyperemesis gravidarum
• Progressive weight loss or cachexia
• Palpable abdominal mass
• Intractable epigastric pain 3, 4

Critical pitfall: Gastric cancer symptoms overlap significantly with normal pregnancy complaints (nausea, vomiting, epigastric discomfort), leading to delayed diagnosis and advanced-stage presentation 5, 6. Maintain high clinical suspicion if symptoms are severe, progressive, or accompanied by alarm features.

Diagnostic Approach

Initial Non-Invasive Evaluation

1. Laboratory assessment:

   • Complete blood count (anemia assessment)
   • Tumor markers: CEA and CA19-9 can assist diagnosis even in pregnancy 3
   • Note: Six of nine pregnancy-associated gastric cancer cases showed elevated CA19-9, with five also showing elevated CEA 3

2. Cross-sectional imaging:

   • Transabdominal ultrasound is first-line and safe
   • MRI without gadolinium if needed for further characterization
   • Avoid CT in first trimester unless absolutely necessary

Endoscopic Evaluation When Indicated

Sedation protocol for first trimester 1:

• Meperidine is the preferred sedative agent
• Minimize or avoid midazolam in the first trimester (can use small doses if absolutely necessary)
• Propofol, fentanyl, and midazolam have not been associated with congenital malformations per ACOG guidance
• Deep sedation requires experienced anesthesiologist

Procedural considerations:

• Position patient in left pelvic tilt or left lateral position to prevent aortocaval compression
• Fetal heart rate monitoring should be considered based on gestational age and facility capabilities
• If cautery needed, place grounding pad on leg or right shoulder/arm (not abdomen)
• Use bipolar cautery preferentially

Absolute contraindications to endoscopy 1:

• Placental abruption
• Imminent birth
• Ruptured membranes
• Hypertensive disease of pregnancy

Tissue Diagnosis

For subepithelial masses, standard forceps biopsy is inadequate 7. Consider:

• Endoscopic ultrasound (EUS): Most accurate for determining wall layer of origin and mass characteristics
• EUS-guided fine-needle aspiration: For masses arising from muscularis propria
• Endoscopic snare resection: For submucosal masses amenable to this approach
• Immunocytochemistry is essential for distinguishing between gastrointestinal stromal tumors, carcinoids, lymphomas, and metastases 7

Management Based on Diagnosis

If Malignancy Confirmed

Gastric cancer in pregnancy carries extremely poor prognosis 3, 6:

• Usually poorly differentiated adenocarcinoma or signet ring cell carcinoma
• Often diagnosed at advanced stages (peritoneal/ovarian metastases common)
• Three-year survival historically only 21% 6

Treatment algorithm:

1. Operable disease: Surgical resection is feasible during pregnancy, preferably second trimester 2

   • Multidisciplinary team coordination essential 1
   • Consider delivery timing based on gestational age and cancer stage

2. Advanced disease: After first trimester, chemotherapy can be administered 8

   • Oxaliplatin-based regimens (SOX, oxaliplatin plus paclitaxel) have been used 3
   • Most chemotherapeutic regimens can be safely administered after first trimester 8

3. First trimester with aggressive disease: Discuss pregnancy termination if maternal survival is threatened

If Benign Mass (e.g., GIST)

• Symptomatic or bleeding: Surgical resection during pregnancy is feasible, preferably second trimester 2
• Asymptomatic, small (<2 cm): May consider surveillance with repeat endoscopy in second trimester
• Note: True malignant potential of individual GISTs cannot be accurately determined by imaging alone 7

Key Clinical Pearls

• Do not withhold necessary procedures solely because of pregnancy 1—maternal health is paramount
• Gastric cancer during pregnancy is rare but devastating; maintain high suspicion with atypical or severe symptoms
• The overlap between pregnancy symptoms and gastric pathology creates diagnostic delay—this is the most dangerous pitfall
• Multidisciplinary coordination (gastroenterology, obstetrics, oncology, anesthesia) is essential for complex cases 1
• Fetal outcomes are generally favorable when appropriate maternal treatment is provided 3, 2