If your cancer is in the lower part of your stomach, you may have a partial gastrectomy to remove this. After the operation, your stomach will be smaller than it was before surgery. However, the operation will not affect the top part of your stomach, where your oesophagus (gullet) feeds into it.f you have surgery to remove the cancer in your stomach, you will probably need to have part or all of your stomach removed. Surgery to remove part of your stomach is known as a partial gastrectomy, and surgery to remove all of your stomach is known as a total gastrectomy.