Cancer centers are contending with shortages of key chemotherapy drugs, with potentially dire consequences once the scarcity starts hitting patients. A new survey released this week by the National Comprehensive Cancer Network (NCCN) found that 93 percent of cancer centers are reporting shortages of carboplatin and 70 percent are reporting shortages of cisplatin. These two drugs are commonly used together to treat a wide variety of cancers — including breast, lung, prostate and many types of leukemias — often with the aim of curing them.