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The Stages of Stomach Cancer

Stomach cancer refers to any one of the types of cancer that begins in the stomach. Upon receiving a stomach cancer (or gastric cancer) diagnosis, the patient also learns what stage the cancer is at. The cancer’s stage is one of the most important pieces of information to decide on the best course of treatment. As well as the stomach the cancer location, the type of cancer present, and a few other vital statistics. Here’s a look at understanding the staging system used for cancer and how that applies to stomach cancers, as well as a brief description of what each stage means. 

Understanding the TNM System

At its simplest, the TNM system stands for the Tumor’s size, the Lymph nodes involvement, and the extent of Metastasization. More specifically, the system is used to identify the how large the tumor has become or how much it has spread. It’s important to know if the cancer has reached any nearby lymph nodes, vital parts of the immune system, as well as the degree to which the cancer has spread, or metastasized, throughout the body. 

Based on this information, each person’s cancer is given a rating from 0-IV, 0 being the smallest, least metastasized, and IV being the largest and most widespread. The latter four stages (I-IV) may be further subdivided and distinguished by letter. For example, IB may refer to a stage I stomach cancer that is more advanced, but not sufficiently advanced to be diagnosed as a II. 

TNM System in Regards to Stomach Cancer

There are more than 4 different types of cancer that can begin in the stomach. Each of these may have slight variances -- for example, carcinoid tumors rarely metastasize, while lymphoma can metastasize very quickly -- and these variances can impact the way staging works. For simplicity’s sake and based on data provided by the Cancer Treatment Centers of America, these stages are largely descriptive of the more common adenocarcinoma, although many aspects are easily transferrable. 

Stage 0

  • Stomach cancer diagnosed at stage 0 means the disease is still in the very earliest stages. Not only has any tumor or cellular growth remained relatively small, the disease has not metastasized beyond the stomach or reached the lymph nodes. It is generally the easiest to treat stage 0 cancer. Unfortunately, stomach cancer can take many years to become obvious or symptomatic, which means it is unlikely to be caught while in this early phase. 

Stage I

Stage I stomach cancer has begun to progress, but remains relatively enclosed.

  • Stage IA refers to a cancer that has begun to move past the mucosa and but has not reached the muscle, nor has it metastasized beyond the stomach or into the lymph nodes.
  • By IB, the cancer meets these conditions in addition to having either grown into the muscle or reached the lymph nodes. No distant sites are affected. 

Stage II

  • Stage IIA refers to stomach cancer that has reached the main muscle and 1-2 lymph nodes; reached the subserosa beneath the muscle but no lymph nodes; or remains in the mucosa but reached 3-6  of the surrounding lymph nodes. No distant sites are affected. 
  • Stage IIB may be distinguished as 7+ affected lymph nodes while remaining in the mucosa; 3-6 lymph nodes and the main muscle; into the subserosa and 1-2 lymph nodes; or has reached the outermost layer of the stomach (the serosa) and no lymph nodes. No distant sites are affected. 

Stage III

  • Stage IIIA stomach cancer has either reached the main muscle and 6-7 lymph nodes; the subserosa and 3-6 lymph nodes; or the serosa and 1-2 lymph nodes. No distant sites are affected.
  • Stage IIIB encompasses the subserosa layer and 7+ lymph nodes; the serosa and 3-6 lymph nodes; or into nearby organs or tissue and 1-2 lymph nodes. No distant sites are affected. 
  • Stage IIIC refers to stomach cancer that has reached the serosa, 7+ lymph nodes, but no other organs, or through the serosa, into nearby organs, and 3+ lymph nodes. No distant sites are affected. 

Stage IV

  • Stomach cancer is diagnosed as stage IV once the cancer begins to metastasize, or reach distant structures in the body, beyond nearby organs, tissues, or lymph nodes. It becomes much more difficult to treat, at this point, because it is in so many different parts of the body. 

Unfortunately, because of the tendency of stomach cancer to become extremely developed before symptoms arise, the Cancer Treatment Centers of America report that “4 out of 5 stomach cancers in the United States are diagnosed after the cancer” has metastasized. If you or a loved one are showing signs of stomach cancer, talk to your doctor as soon as possible to get a good diagnosis and a strong chance at treatment. 

Last Updated: July 28, 2017