HOUSTON --There's a growing national shortage of hospital drugs. It's reported to be the largest shortage in decades. Many of the drugs in short supply are cancer drugs, and that shortage is only getting worse. So in Houston, are cancer patients here finding the chemotherapy drugs they need? At M.D. Anderson, they now color code chemotherapy drugs because so many are in short supply nationally. "Red here means we're unable to get the drug under any circumstance," said MD Anderson Clinical Pharmacy Manager Wendy Smith, PhD. "These are four of the ones we're keeping a close eye on." Drugs for breast cancer, leukemia, colon cancer and testicular cancer. "It's worrying me and everyone else including the patients," Smith said. "It's a big stress factor; to factor into the whole treatment and diagnosis," said Debbie Leighton, a breast cancer patient. Leighton didn't need chemotherapy when she was treated for breast cancer last year, but worries that if she did would the drug she needed be there for her? "Then to find out, oh, it's not available. So then what do you do?" Leighton said. At Texas Children's Hospital, a few children with cancer have been affected by the shortage, too. They tell me the children were given comparable chemotherapy drugs. But doctors there are concerned, too. "These shortages are really at a crisis level," said Dr. Adan Rios of the University of Texas Health Medical School. Dr. Rios treats adults at Memorial Hermann Hospital. Oncologists sometimes must transition patients from one chemotherapy to another because of the shortage. "But the alternative had similar efficacy rates, so it worked the same way," said Smith. But everyone worries about the day the best drug just isn't there. "There are going to be patients who may be seriously affected or may die from the absence of these drugs," said Dr. Rios. It's harder for oncologists with fewer patients. M.D. Anderson's size gives it an advantage -- more suppliers. But no one knows why these drug shortages keep happening. "Drug manufacturers are not required to tell us or the FDA why there's a manufacturing shortage," Smith said. The Food and Drug Administration is allowing some drugs in from Europe, but it's not helping much. "We're seeing drug shortages for more critical drugs that last longer," said Smith. And as drug shortages continue, it becomes one more thing for cancer patients to worry about.