A surge in demand for hospital services has seen hundreds more people turn up for treatment at accident and emergency.
In the first half of this month attendances at A&E departments at Mid Yorkshire Hospitals Trust were up by around 500 each week compared to last December.
Bosses at the trust, which runs Pinderefields, Pontefract and Dewsbury Hospitals, are pleading with people only to go to A&E in a genuine emergency as services struggle to cope.
The trust has also missed targets to see A&E patients within four hours.
And patients, including people waiting for cancer surgery, are having operations cancelled at short notice.
Geraldine Wallbank, 63, has had an operation for bladder cancer at Pinderfields rescheduled twice.
Former nurse Mrs Wallbank, of Townville, Castleford, said: “I should have had the operation over and done with by now.
“Until it’s operated on we won’t know what grade of cancer it is and how fast it has been growing. That concerns and worries me.
“Having to spend Christmas with this hanging over me is not pleasant.”
Latest figures show that 187 patients waited for between four and 12 hours in A&E in the week ending December 14, up from 113 the previous week.
In the first week of December there were 4,515 A&E attendances at Mid Yorkshire, compared to 3,937 in the same week last year.
Ambulances have also been queuing outside hospitals because of delays getting patients into hospitals.
Over the same weekend of December 12, 47 ambulances were delayed for more than 30 minutes when handing over patients for treatment at A&E departments, NHS England figures show.