You need at least one lung to breathe, but the other can be removed to treat lung cancer, tuberculosis, or other lung diseases. Breathing is harder but still possible when one of the organs is removed; patients lose about 35 percent of the volume of air they can exhale in a second, according to a study in the journal Respiratory Care. “The lung is a fixed cavity in the chest, so it can’t really get bigger,” says Julie Heimbach, MD, transplant surgeon and surgical director of liver transplantation at Mayo Clinic. (Don't miss these signs of lung cancer you should never ignore.)
Patients with bladder cancer or, on rare occasion neurogenic bladder (when a problem with the nervous system affects bladder control), will need the organ removed—and the prostate and lymph nodes or uterus, ovaries and possibly part of the vagina along with it, says Georges-Pascal Haber, MD, PhD, urologist with Cleveland Clinic. Doctors use a piece of intestine to divert urine that used to be stored in the bladder. The intestine can either form a “neobladder” that pushes urine out through the urethra, an “Indiana pouch” that patients manually drain with a thin tube, or an “ileal conduit urinary diversion” that sends urine into a bag outside the body, says Dr. Haber. Because a neobladder or Indiana pouch can’t sense when it’s full like the bladder does, patients might need to set alarms every three or four hours to remind them to empty it, but life will basically go back to normal. “They start to recognize when the bladder is full through hot flashes or different symptoms,” says Dr. Haber. (Here are 13 more things your bladder wants to tell you.)
With some weight-loss surgeries—and for aggressive stomach cancers that haven’t spread to other parts of the body—patients might have part or all of their stomach removed. (Learn about the mysterious stomach pain that's often mistaken for cancer.) Normally, the stomach absorbs vitamins and jump-starts digestion by mixing foods with acids to break them down. Once the stomach is gone, surgeons will connect the esophagus directly with the small intestine. After surgery, patients can still eat solid food, but they’ll only be able to handle smaller quantities and might need to avoid certain foods to avoid “dumping syndrome” when the food passes quickly into the small intestine, says Abdullah Shatnawei, MD, gastroenterologist at Cleveland Clinic. “As food is dumped into the small bowel, sensations of dizziness, lightheadedness, sweating can occur, as well as bloating, satiety, fullness,” he says. They might also need a sudden trip to the bathroom.
The spleen’s main function is filtering blood, but it might be removed if it’s damaged or diseased, such as for the blood disorder, idiopathic thrombocytopenic purpura. Because it plays an important role in the immune system, patients are more likely to get sick once it’s removed. “We do have to give patients who are getting their spleen removed certain vaccinations because they are going to be more at risk for certain infections,” says Dr. Heimbach.
The function of the appendix isn’t totally clear. Some experts think it’s a useless organ that served a purpose for our ancestors, while recent research suggests it might be keeping “good” bacteria safe. For some people, though, it does more harm than good. “It does get blocked up and infected and has to be removed sometimes,” says Dr. Heimbach. Even if it does play a role in immunity, there haven’t been any long-term health effects associated with getting an appendix removed.