A regional centre for pancreatic cancer surgery is being created in Cambridge giving rise to concerns about travelling times for patients.
The East of England Specialised Commissioning Group (EoE SCG) said it had consulted widely and had concluded that survival rates would improve.
The specialised team of surgeons will be based at Addenbrooke's Hospital.
The director of EoE SCG, Trevor Myers, said the move could "cause stress and hardship for some people".
From 2010 it will serve patients from Bedfordshire, Cambridgeshire, north east Essex, Norfolk and Suffolk.
The EoE SCG said national evidence showed that the new arrangement would improve the survival chances for patients.
It would improve the ability of local teams to diagnose pancreatic cancer and offer the latest surgical techniques at the specialised centre in Cambridge, it said,
Dr Rory Harvey, consultant medical physician at Bedford Hospital NHS Trust and chair of the Pancreatic Cancer Project steering group, said: "Although the centre of the network will be in Cambridge, most patients with pancreatic cancer will still receive their care at their local hospital.
"It is thought that up to 40 people will need to travel to Cambridge, where before they may have gone to Ipswich or Norwich."
Local teams will continue to do other types of pancreatic and gastro-intestinal surgery.
Currently there are teams providing pancreatic cancer surgery in Cambridge, Ipswich and Norwich.
The EoE SCG said the proposal was broadly supported by the public during a four month consultation but many respondents were concerned about the difficulties for those who may have to travel longer distances.
Other concerns came from doctors, other NHS staff and public representatives in Suffolk and Essex who are worried about the possible negative impact on current services at Ipswich Hospital.
Trevor Myers, director of the EoE SCG, said: "If patients have to travel further... undoubtedly this may cause stress and hardship for some people, but this will be off-set by the greater chances of survival for those with pancreatic cancer.
"We will, of course, do everything possible to minimise any problems travelling may give patients and their families."