A half-a-million-pound donation could be lost if a decision isn't made soon on whether Kendal's getting its own radiotherapy unit.
A benefactor has left a legacy of £500,000 to go towards the proposed unit at Westmorland General Hospital - but the offer expires in June.
A pledge to fund the £15million pound cancer treatment facility was secured from the Treasury more than a year ago.
However, nothing can be done until a national review of radiotherapy services is complete - South Lakes MP Tim Farron is pressing NHS England to finish it.
Mr. Farron said: “This review is dragging on – local people, and in particular those who currently have to travel regularly to Preston for treatment, want to see a decision made about radiotherapy services in Kendal.
“The government recommends that patients should not have to travel for more than 45 minutes to access radiotherapy services, yet we all know that the vast majority of South Lakeland residents live further than this from Preston. It is unacceptable that local people have to travel so far to access such essential services.
“The fact that an individual generously left half a million pounds for the establishment of a radiotherapy unit in Kendal, which will be lost if the unit is not given the go-ahead by June, adds extra urgency to the situation. A decision must be made without delay.”