Anemia
The bone marrow is responsible for the production of white and red blood cells. Our blood is responsible for the transfer of oxygen and nutrients to the cells. During cancer, when the tumor is well grown and have developed blood vessels for its nutrition, it becomes prone to bleeding. The patient starts losing blood cells at a faster rate than the formation rate. This blood loss results in less supply of oxygen to the cells. Half of the patients with gastric cancer are found to be iron deficient due to associated malabsorption of nutrients. Moreover, when the cancer treatments are started, they further kill the red blood cells. Energy and nutrient absorption in the blood is also affected due to less hemoglobin level.