Since 2009, the number of oncology practices affiliated with hospitals has doubled. And a new report says that has driven prices up by 30 percent in areas where there have been such tie-ups.

“This type of consolidation increases spending,” said the University of Chicago’s Rena Conti, the author of the new report. “We do not know whether this increased spending is really going to translate into better quality or better access for cancer patients.”

For years, hospitals have argued these deals could improve coordination, reduce duplication and eliminate waste, lowering spending overall.

But this paper adds to a growing body of literature that healthcare mergers are a serious concern.

Wharton’s Robert Town predicts if this keeps up, regulators like the Federal Trade Commission and the Department of Justice will crack down.

“You are going to see a meaningful impact on anti-trust policy,” Town said. “The FTC and DOJ are going to be less favorably disposed to these types of mergers.”