Stomach cancer most commonly spreads to the liver, the peritoneum (the lining of the abdominal cavity), the lungs, and the bones. In a large study of patients with metastatic gastric cancer, the liver was involved in 48% of cases, the peritoneum in 32%, the lungs in 15%, and the bones in 12%. About 36% of people with stomach cancer already have distant spread at the time of their first diagnosis.
The Four Most Common Sites
The liver is the single most frequent destination for stomach cancer cells that enter the bloodstream. The stomach’s blood supply drains partly through the portal vein, which flows directly to the liver, giving cancer cells a direct route. Once in the liver, tumors can interfere with the organ’s ability to process waste, which is why liver metastases often cause yellowing of the skin and eyes (jaundice), fatigue, and upper-right abdominal pain.
The peritoneum ranks second. This is the thin membrane lining the inside of the abdomen and covering the organs within it. When stomach cancer penetrates the outer wall of the stomach, cells can shed directly onto this surface and seed new tumors across the abdominal cavity. This type of spread often triggers a buildup of fluid in the abdomen called ascites, which causes visible swelling, bloating, and discomfort. About 85% of people with peritoneal involvement report nonspecific abdominal symptoms and fluid accumulation.
Lung metastases develop when cancer cells travel through the bloodstream and lodge in the small blood vessels of the lungs. Symptoms can include a persistent cough, shortness of breath, or chest pain, though small lung metastases sometimes produce no symptoms at all and are found only on imaging.
Bone metastases cause deep, aching pain that tends to worsen at night or with activity. They can also weaken bones enough to cause fractures from minor stress.
Spread to Lymph Nodes
Before stomach cancer reaches distant organs, it typically travels through the lymphatic system. The stomach is surrounded by clusters of lymph nodes grouped along its blood vessels: nodes along the lesser and greater curvatures of the stomach, nodes near the pylorus (where the stomach meets the small intestine), and nodes along the major arteries that feed the stomach. These are considered “regional” lymph nodes, and cancer found only here is classified as regional-stage disease rather than distant metastasis.
When cancer moves beyond these regional stations, it can reach nodes farther away. One classic sign is an enlarged lymph node just above the left collarbone, historically called Virchow’s node. A hard, painless lump in this location can be the first clue that a cancer deep in the abdomen has spread upward through the lymphatic chain. Swollen lymph nodes from cancer feel like firm lumps under the skin and are usually painless.
Less Common but Notable Spread Patterns
Stomach cancer occasionally spreads to the ovaries, producing what’s known as a Krukenberg tumor. These ovarian metastases are more often found on both sides and tend to grow large, sometimes becoming the first noticeable sign of a stomach cancer that was otherwise too small to cause symptoms. Krukenberg tumors account for only 1% to 2% of all ovarian tumors, but when one is found, the primary source is most often the stomach.
Another rare but distinctive sign is a hard nodule at the belly button, sometimes called a Sister Mary Joseph nodule. This is a skin metastasis from an abdominal cancer, and its presence indicates advanced disease. Both of these patterns are uncommon, but they’re clinically important because they can be the first visible evidence of a hidden stomach cancer.
Why Cancer Favors Certain Organs
The pattern of spread isn’t random. A concept known as the “seed and soil” hypothesis explains that cancer cells (the seeds) can only take root in organ environments (the soil) that provide the right conditions for growth. The liver and lungs are common landing sites partly because of blood flow patterns: both organs filter large volumes of blood and have dense networks of tiny blood vessels where circulating tumor cells can get physically trapped. But mechanical trapping alone doesn’t explain everything. The chemical environment of the destination organ matters too. Cancer cells that successfully colonize the liver, for example, have molecular features that let them survive and multiply in liver tissue specifically.
Peritoneal spread follows a different logic entirely. Instead of traveling through blood or lymph, cancer cells physically drop off the outer surface of the stomach and drift across the abdominal cavity, settling on nearby tissues. This is why tumors that have grown through the full thickness of the stomach wall carry a much higher risk of peritoneal involvement.
How Spread Is Detected
CT scans are the primary tool for identifying distant metastases. They’re particularly good at spotting liver tumors, enlarged distant lymph nodes, and lung nodules, with specificity above 93% for most sites. For peritoneal spread, however, CT is less reliable, catching only about 44% of cases. Small tumor deposits scattered across the peritoneum are difficult to see on any scan.
PET/CT scans, which highlight areas of high metabolic activity, can sometimes reveal metastases that CT alone misses. In one study, PET/CT found distant disease in 10% of patients whose cancer appeared localized on other imaging. PET/CT also appears to be better than traditional bone scans for detecting bone metastases. However, PET/CT is poor at finding peritoneal spread, with sensitivity as low as 22%.
Because no imaging method reliably rules out peritoneal disease, doctors often perform a staging laparoscopy for locally advanced stomach cancer. This is a minimally invasive procedure where a small camera is inserted into the abdomen to directly inspect the peritoneal surfaces. It remains the most sensitive way to confirm or exclude peritoneal involvement before treatment planning begins.
What Spread Means for Prognosis
The stage at which stomach cancer is found has a dramatic effect on outcomes. When the cancer is still confined to the stomach, the five-year relative survival rate is about 76.5%. Once it has spread to regional lymph nodes, that drops to 37.2%. For cancer that has reached distant organs, the five-year survival rate falls to roughly 7.5% to 8%, based on data from the National Cancer Institute’s SEER program covering diagnoses between 2015 and 2021.
The specific organs involved also matter. Liver metastases and ascites from peritoneal disease both independently worsen the outlook. Survival rates are statistical averages, though, and individual outcomes vary depending on the number and size of metastases, how the cancer responds to treatment, and the person’s overall health. Newer treatment approaches, including targeted therapies and immunotherapy, have expanded options for people with metastatic stomach cancer beyond what was available when much of this survival data was collected.