Getting diagnosed with stomach cancer can feel overwhelming—but understanding the process helps. You might be wondering: How do doctors know it’s stomach cancer? What tests are actually done? And what happens after that first worrying symptom? Let’s break it down, step by step, in everyday language—no fluff, no jargon, just facts that make sense.
What Are the Early Signs That Lead to Testing?
It usually starts with something small—maybe you’ve had persistent indigestion, feel bloated after meals, or you’ve been losing weight without trying. Sounds familiar?
Doctors often begin testing when symptoms like these don’t go away after a few weeks:
- Persistent upper abdominal pain
- Nausea or vomiting (especially if it contains blood)
- Feeling full quickly after eating
- Unexplained weight loss
- Black or tarry stools (a sign of bleeding)
If these symptoms keep hanging around, your doctor might say, “Let’s take a closer look.”
Initial Clinical Assessment and Physical Exam
Before any machines or scopes are involved, it all starts in the consultation room.
The doctor will ask about your symptoms, medical history, and any risk factors (like smoking, family history, or a previous H. pylori infection). They’ll also examine your abdomen, check for tenderness or swelling, and might ask questions like:
- “Have you noticed a loss of appetite?”
- “Is the pain worse after eating?”
- “Any changes in your stool?”
It’s the groundwork that sets the direction for what comes next.
Blood Tests: What Can They Reveal?
Can a blood test diagnose stomach cancer? Not directly. But it can drop some important hints.
Your doctor may order:
- Complete Blood Count (CBC) to check for anaemia, which might indicate slow bleeding inside the stomach.
- Liver function tests to see if the cancer may have spread.
- Tumour markers like CEA (Carcinoembryonic Antigen) or CA 19-9—these are proteins that may be elevated in some stomach cancers, though not specific enough for a firm diagnosis.
So while blood tests don’t confirm cancer, they often raise red flags that say, “We need to dig deeper.”
Upper Endoscopy (Gastroscopy): The Gold Standard
This is the real game-changer.
In an upper endoscopy (also called gastroscopy), a thin flexible tube with a camera (endoscope) is passed through your mouth and into your stomach. Sounds scary? Don’t worry—sedation is usually given, and it’s over in about 15 minutes.
Here’s what makes it so crucial:
- It allows doctors to see the inside of your stomach in real time.
- They can spot abnormal areas, ulcers, or suspicious growths.
- Most importantly, they can take biopsies (tiny tissue samples) for lab testing.
If there’s any one test that gives stomach cancer away, it’s this one.
Biopsy: Confirming the Diagnosis
Once a suspicious lesion is seen during endoscopy, the next question is: Is it cancer?
That’s where biopsy comes in. The tiny samples taken are examined under a microscope by a pathologist, who checks for the presence of cancer cells.
Only a biopsy can confirm if it’s really stomach cancer, what type it is (like adenocarcinoma), and how aggressive it might be.
This is the point where “possible cancer” becomes “definite diagnosis.”
Imaging Tests to Check for Spread
Once cancer is confirmed, doctors need to see how far it’s gone. That’s called staging. And for that, imaging is key.
- CT Scan (Computed Tomography): A detailed 3D X-ray that shows the tumour and whether it has spread to lymph nodes, liver, or lungs.
- PET Scan (Positron Emission Tomography): Highlights active cancer cells in the body using a special dye.
- MRI (Magnetic Resonance Imaging): Useful for soft tissues and sometimes liver involvement.
These scans help answer crucial questions: Is surgery possible? Has the cancer spread? What’s the best treatment plan?
Endoscopic Ultrasound (EUS)
Here’s where it gets more precise.
Endoscopic ultrasound combines endoscopy and ultrasound to get closer images of the stomach wall and nearby structures. It’s often done after the first endoscopy, especially when surgery is being considered.
It helps determine:
- How deep the tumour has grown into the stomach wall
- If nearby lymph nodes are involved
- Whether nearby organs are affected
Think of it as the “zoom-in” tool for the cancer’s details.
Barium Swallow (Upper GI Series): Is It Still Used?
You might have heard about drinking a chalky liquid and having X-rays taken afterward. That’s a barium swallow.
Although it’s not the first-line test anymore, it can still be useful when:
- Endoscopy isn’t available or tolerated
- There’s a need to look at how food moves through the upper GI tract
It’s more of a backup tool these days—but still has a place in specific scenarios.
Laparoscopy: Looking Inside the Abdomen
This is a minor surgical procedure, but it gives big answers.
During laparoscopy, a surgeon inserts a camera through a small incision in your belly to look directly at your stomach and surrounding organs. It’s often done before surgery to:
- Look for hidden metastases (especially in the liver or peritoneum)
- Take biopsies if needed
- Help plan the safest and most effective surgery
Sometimes cancer can be more widespread than scans show—and laparoscopy catches what others miss.
Staging Investigations: Understanding the Cancer’s Extent
Doctors use a system called TNM staging:
- T = Tumour size and depth
- N = Lymph Node involvement
- M = Metastasis (spread to other organs)
This staging guides the treatment. For example:
- Stage I may be treated with surgery alone.
- Stage III or IV often needs chemotherapy or targeted therapy first.
So when you hear, “We’re staging the cancer,” they’re building the roadmap for treatment.
Molecular Testing and HER2 Status
Not all stomach cancers behave the same—and not all respond to the same treatments.
That’s why some biopsies are tested for HER2, a protein that, if positive, means targeted drugs like trastuzumab (Herceptin) may be effective.
Other emerging tests might look for PD-L1 expression or microsatellite instability, which could open the door to immunotherapy.
This is the era of personalised treatment—and molecular testing is the key to unlocking it.
How Long Does Diagnosis Take?
This is the part no one likes to wait for.
From your first symptom to a confirmed diagnosis can take anywhere from a few days to a couple of weeks, depending on:
- How soon you see a doctor
- How quickly tests and biopsies are scheduled
- Lab turnaround times
If things feel slow, don’t hesitate to ask, “Can we speed this up?”—you deserve answers, and fast.
What Happens After Diagnosis?
Once all the tests are done, a multidisciplinary team (MDT)—which may include a gastroenterologist, surgeon, oncologist, and dietitian—meets to discuss your case.
Then comes the treatment plan:
- Surgery
- Chemotherapy
- Radiation
- Targeted therapy
- Or a combination of these
You’ll also receive emotional and nutritional support, because healing is not just physical—it’s mental, too.
Final Thoughts
Getting diagnosed with stomach cancer is a journey—one filled with scans, scopes, and decisions. But each test has a purpose. Each result adds clarity. And each step brings you closer to a plan for recovery.
If you’re navigating this process, know this: You’re not alone. Ask questions, stay informed, and take it one test at a time.
References
- Stomach Cancer Diagnosis – American Cancer Society (2023). https://www.cancer.org/cancer/stomach-cancer/detection-diagnosis-staging/how-diagnosed.html
- Tests for Stomach Cancer – Cancer Research UK (2023). https://www.cancerresearchuk.org/about-cancer/stomach-cancer/getting-diagnosed/tests
- Gastric Cancer: Diagnosis and Staging – National Cancer Institute (2024). https://www.cancer.gov/types/stomach/patient/stomach-treatment-pdq#_115
- Endoscopic Ultrasound for GI Cancers – Johns Hopkins Medicine (2022). https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/endoscopic-ultrasound-eus