Rapid Gastric and Pancreas Cancer Staging Utilizing Peritoneal Lavage

This study is being done to develop a new method that can rapidly stage patients with gastric and pancreas cancer. Staging means finding out what is the extent of the cancer in a patient's body. Currently before patients have the surgery to remove their cancer, a surgical exam is done in the operating room to see if their cancer has spread. A thin tube-like instrument with lens and a light is placed into the abdomen. This is done by making small cuts into the body. This exam is called a diagnostic laparoscopy. If cancer spread is not seen, fluid is put into the abdomen and then taken out. This is called "lavage" or washing. The fluid is then looked at in a laboratory. If the fluid contains cancer cells surgery is often delayed. The investigators are testing a new method to put the fluid into the abdomen. It is called percutaneous lavage. Percutaneous means "through the skin". A needle is put through the skin into the abdomen. Tubing is then placed over the needle so that fluid can be put into the abdomen and then taken out. The fluid is then looked at in a laboratory. The investigators want to see if the two methods are equal because if they are equal, in the future, patients may be able to have this procedure done outside of the operating room.