A report by the Care Quality Commission (CQC) has found a number of cancer patients suffered "undue delays" at Colchester Hospital University NHS Foundation Trust.
A spokesman said that of the 61 care records examined, 22 showed that people had been "placed at risk of receiving care that was unsafe or not effective, due to delays in receiving appointments or treatment".
The CQC said that the trust has written to 30 patients, or their next of kin - where patients have died, offering to review their treatment.
The Chief Inspector of Hospitals Sir Mike Richards said "It is shocking to think that people's lives may have been put at risk for the sake of the waiting time figures".
He has recommended that the hospital should be put into special measures
More top news
Overnight it will be cooler and fresher but most places will stay dry with a nippy start to Sunday.
X Factor contestant Raign seems to impress the Wembley audience with her own song even though Cheryl finds her "really annoying".
YouTube superstar Alfie Deyes got a sense of how far he has come when thousands of fans descended on his latest book signing in London.