That means patients may have to choose between the insurer and the hospital, The Boston Globe reported.

The contract between Tufts Medical Center and the Blue Cross Blue Shield HMO ends Jan. 31.

Ellen Zane, the hospital's chief executive officer, said that the payments Blue Cross makes to Tufts are 20 to 40 percent below those to other major teaching institutions. She told the Globe that the hospital has tried to negotiate a rate increase for 11 months and has no choice but cancellation unless Blue Cross changes its position by the end of the month.

In a letter to patients, Tufts invited them to "express their frustration" to the insurer.

Jay McQuaide, a spokesman for Blue Cross, said the hospital was using a "negotiating tactic." He said that Tufts was seeking a larger increase than other hospitals.