Cancer drug prices have risen dramatically since the early 2000s, especially in the U.S. Some doctors are beginning to balk at medications that, in some cases, can cost over $10,000 a month and often offer only marginal improvements in survival. Other drugs do produce dramatic increases in life expectancy, but accumulating expenses force patients to stop treatment. Several aspects of the U.S. drug market contribute to high prices, including long patent durations that shield drug makers from competition, and Medicare’s inability to negotiate better prices with drug makers. Health authorities in several other countries have started to refuse coverage for drugs that, in their estimation, do not offer enough benefit to warrant their high cost. Notably, cancer drug prices in those countries are significantly lower than in the U.S. In 2012, Memorial Sloan-Kettering Cancer Center became the first major U.S. hospital to refuse offering a cancer drug–zif-aflibercept (Zaltrap)–due to price concerns.