WASHINGTON - The global market for cancer drugs will grow twice as fast as that for all other pharmaceuticals as the developing world spends more on health care, a new report says.

China, Brazil, Russia and other emerging countries are becoming bigger customers for pharmaceuticals as they invest more in treating and diagnosing cancer, according to a report issued by IMS Health.

The health care research firm expects pharmaceutical spending in countries such as India, Mexico and Turkey to grow by 12 percent to 13 percent over 15 years, compared with single-digit growth for more developed nations.

Cancer drug spending is expected to grow 12 percent to 15 percent annually through 2012 to $75 billion to $80 billion, according to the report. The overall drug market is expected to grow 6.4 percent.

Feeding that demand are the multibillion-dollar research and development budgets of companies like Genentech, Amgen and Novartis.

"Oncology is the top of the bill when it comes to new products in development," said Titus Pattel, a vice president with IMS. "Oncology R&D dwarfs all other research efforts within these organizations."

Cancer drug sales are expected to reach $48 billion this year, led by Genentech's breast cancer drug Herceptin, Novartis' leukemia drug Gleevec and other blockbusters.

But the market is not immune to a slowdown. Expiring patents on older cancer drugs and efforts to tighten health care spending could limit future growth, according to IMS.

Some European countries have begun paying drug companies based on how successfully their drugs treat patients. The Italian government, for example, only began reimbursing Johnson & Johnson for the cancer treatment Velcade after the drug demonstrated positive results in patients. IMS said that the adoption of similar policies in the U.S. could slow spending on cancer medications.

Pharmaceutical companies also face a tougher regulatory environment in the U.S., where the Food and Drug Administration has delayed some highly anticipated cancer therapies.

An aggressive review environment could dampen the market for between 25 and 30 new anti-cancer drugs under development, the IMS report says. At the same time, some of the biggest blockbuster cancer drugs of the last decade will lose their patent protection, including Sanofi-Aventis' Taxotere and AstraZeneca's Arimidex.