For cancer patients already dealing with the extreme stress of their illness, a myriad of surging costs can add to the worry of treatment. UnitedHealthcare, the biggest U.S. health insurer, is taking aim at controlling costs of treatment with a new pilot program that will provide a set sum for a patient's coverage. The plan is being developed with the University of Texas MD Anderson Cancer Center and will enroll about 150 patients at first, the insurer said in an email to CBS MoneyWatch. Terms of the contract are confidential, but the idea of paying a set sum for treatment is a shift away from the typical per-service payment that Americans are familiar with.