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Stage 3

The stage of a cancer tells you how big it is and how far it’s spread. 

What is stage 3 stomach cancer?

Stage 3 stomach cancer means your cancer has grown into or through the inner, supportive, muscle or outer layer of the stomach. It might have spread to nearby lymph nodes. But it hasn't spread to other organs or distant body parts. 

This is a simplified description. We have more detailed information below.

Staging systems

Doctors use different systems to stage stomach cancer. This page is about stage 3 cancer, which is part of the number staging system. This system has 5 stages, stage 0 to stage 4.

This page also tells you what stage 3 means in the TNM system. This system describes:

  • the size of the primary tumour (T)
  • whether the cancer has spread to the lymph nodes (N)
  • whether the cancer has spread to another part of the body (M)

How do doctors find out your stage?

There are different ways to find out your stage. Your doctor might use:

  • clinical staging before treatment and if you don't have surgery
  • pathological staging if you do have surgery
  • post neoadjuvant staging if you have chemotherapy before surgery

Clinical staging means the doctor stages you after examining you and looking at test and scan results. Doctors use clinical staging to plan your treatment. It’s also the best way to stage people who aren’t having surgery. You might see your clinical stage written as cTNM.

Pathological staging means the doctor stages you after examining the tissue that the surgeon removes during an operation. This is also called surgical staging. The doctors combine your clinical stage results with the surgical results. Pathological staging is generally a more precise way to find out how far your cancer has spread. Your pathological stage might be different to your clinical stage. You might see your pathological stage written as pTNM.

Post neoadjuvant staging means you have had chemotherapy before surgery (neoadjuvant treatment) and the doctor stages you again after surgery. You might see your post neoadjuvant stage written as ypTNM. 

For stomach cancer, the clinical, pathological, and post neoadjuvant staging are all different. In this section we describe the pathological and clinical stages.

What is stage 3 stomach cancer (clinical staging)?

Clinical staging means your doctor uses test and scan results to stage your cancer.

In clinical staging, stage 3 stomach cancer means your cancer has grown into or through the outer lining of your stomach. It has spread to any number of nearby lymph nodes. But it hasn't spread to other organs or distant body parts. 

In the TNM system, this is the same as one of the following:

  • T3, N1,2 or 3, M0
Diagram showing stage 3 stomach cancer (clinical staging) 1 of 2
  • T4a, N1, 2 or 3, M0
Diagram showing stage 3 stomach cancer (clinical staging) 2 of 2

What is stage 3 stomach cancer (pathological staging)?

Pathological staging means the doctor stages you after examining the tissue that the surgeon removes during an operation. 

In pathological staging, stage 3 stomach cancer is split into 3 groups - stage 3A, 3B and 3C.

Stage 3A means the cancer has grown into or through the muscle or outer layer of the stomach and there is cancer in nearby lymph nodes. Or the cancer has grown through the stomach wall and into nearby organs or tissues, but it hasn’t spread to any lymph nodes. It hasn't spread to distant body parts.

In the TNM system, this is the same as one of the following:

  • T2, N3a, M0
Diagram showing stage 3A stomach cancer (pathological staging) 1 of 4
  • T3, N2, M0
Diagram showing stage 3A stomach cancer (pathological staging) 2 of 4
  • T4a, N1 or N2, M0
Diagram showing stage 3A stomach cancer (pathological staging) 3 of 4
  • T4b, N0, M0
Diagram showing stage 3A stomach cancer (pathological staging) 4 of 4

Stage 3B means the cancer has grown into or through the inner, supportive, muscle or outer layer of the stomach. Or the cancer has grown through the stomach wall and into nearby organs or tissues. There is cancer in nearby lymph nodes but it hasn't spread to distant body parts.

In the TNM system, this is the same as one of the following:

  • T1 or T2, N3b, M0
Diagram showing stage 3B stomach cancer (pathological staging) 1 of 3
  • T3 or T4a, N3a, M0
Diagram showing stage 3B stomach cancer (pathological staging) 2 of 3
  • T4b, N1 or N2, M0
Diagram showing stage 3B stomach cancer (pathological staging) 3 of 3

Stage 3C means the cancer has grown into or through the outer layer of the stomach. Or the cancer has grown through the stomach wall and into nearby organs or tissues. There is cancer in nearby lymph nodes but it hasn't spread to distant body parts.

In the TNM system, this is the same as one of the following:

  • T3 or T4a, N3b, M0
Diagram showing stage 3C stomach cancer (pathological staging) 1 of 2
  • T4b, N3a or N3b, M0
Diagram showing stage 3C stomach cancer (pathological staging) 2 of 2

Treatment

The stage of your cancer helps your doctor to decide what treatment you need. Treatment also depends on:

  • your type of cancer (the type of cells the cancer started in)
  • where the cancer is in your stomach
  • other health conditions

You usually have surgery to remove all of or a part of your stomach. And have chemotherapy before and after surgery. 

If you haven't had chemotherapy before surgery then you might have:

  • chemotherapy combined with radiotherapy  (chemoradiotherapy) after surgery
  • chemotherapy on its own after surgery

If you aren't having surgery

Other health problems might mean you can’t have surgery, or you may decide you don’t want it. You will have tests to check how fit you are before you have any treatment including heart and lung tests.

The main treatment is chemotherapy. You may have radiotherapy.

About other stages

Last reviewed: 
26 Aug 2020
Next review due: 
25 Aug 2023
  • AJCC Cancer Staging Manual (8th Edition)
    M Amin and S Edge.
    Springer, 2017.

  • Gastric cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up 
    E Smyth and others, 
    Annals of Oncology, 2016. Volume 27, Pages v38–v49

  • Guidelines for the management of oesophageal and gastric cancer
    Association of Upper Gastrointestinal Surgeons of Great Britain and Ireland, the British Society of Gastroenterology and the British Association of Surgical Oncology
    Allum (and others)
    Gut 2011;60:1449-1472

  • Gastric cancer
    Custem EV. (and others)
    The Lancet, 2016. 5th May S0140-6736(16)30354-3

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