William Richardson, 81, had been diagnosed with oesophageal cancer in August 2018 while serving a 16-year prison sentence for rape and indecency at HMP Wakefield.
He was jailed in August 2014 for offences committed between 1976 and 1999 against five children, the youngest of whom was five.
The Prisons and Probation Ombudsman, which investigates all deaths in custody, found that overall his care had been of the standard he could have expected to receive in the community.
A clinical reviewer said a lump found under Mr Richardson's ear in April 2018 had warranted a referral under the suspected cancer pathway rather than the referral given for an ultrasound.
The ombudsman's report said this might have resulted in an earlier diagnosis for Mr Richardson, although the reviewer could not say whether this would have affected the eventual outcome.
Ombudsman Sue McAllister noted that Mr Richardson was escorted to hospital in restraints on a number of occasions between May and October 2018, but said she was not satisfied that his age and health were taken into account when deciding whether restraints were needed.
Mr Richardson spent time on the prison's palliative care ward after being given a diagnosis of terminal cancer in August 2018 and died on February 13 last year.
In her report, Ms McAllister said: "We found that the prison’s family liaison officer (FLO) kept in regular contact with Mr Richardson’s family during his illness. However, shortly after Mr Richardson died, the FLO took leave but did not hand over the FLO duties to another member of staff. This meant that Mr Richardson’s family were not adequately supported before his funeral.
"We commend Wakefield for making considerable efforts to enable Mr Richardson’s family to spend as much time as possible with him in the period before he died."
The report made three recommendations around assessing the need for restraints, ensuring handovers take place if a FLO goes on leave explaining the prison regime to families spending time with dying prisoners.
An action plan published alongside it notes that all the recommendations were accepted and action has been taken on each point.
A spokeswoman for Care UK, the prison's healthcare provider, said: “Our teams are deeply committed to supporting patients and the healthcare team worked with hospital colleagues to ensure they fully understood and were able to support Mr Richardson’s treatment. They then cared for Mr Richardson in the centre’s highly regarded palliative unit throughout his illness and worked with him to plan his end-of-life care, in line with the Dying Well in Custody guidelines.
“The PPO report praises the team’s commitment to facilitating Mr Richardson’s family’s extended visits as an innovation in a high security prison. The report also found the care he received was at the same level he would have received in the community.
“Whilst there is no certainty that adopting the initial two-week cancer pathway would have made a difference to the outcome, additional training has been put in place around recognising and referring prisoners who have suspected cancer.”