Doctors treating Emperor Akihito of Japan for prostate cancer are confident he will make a full recovery.

Tests following the emperor's surgery last week showed the cancer had not spread.

We believe the removal (of the cancerous prostate) will lead to complete recovery Ichiro Kanazawa, imperial household agency

"We believe the cancer had been wholly contained in the removed part," Ichiro Kanazawa, medical supervisor for the imperial household agency, told a news conference.

"We believe the removal (of the cancerous prostate) will lead to complete recovery," he said.

The emperor is expected to remain in hospital until next month.

During this time, his constitutional duties have been assumed by Crown Prince Naruhito.

Break with tradition

The news that the emperor was suffering from prostate cancer was given at the end of last year.

The announcement marked a break with tradition for the highly secretive imperial household.

The previous emperor died in 1989 before it was revealed that he too had been suffering from cancer.

Emperor Akihito was treated in a public hospital - the first time a Japanese emperor has undergone surgery outside the palace grounds.

These initiatives are being seen as part of a modest drive to modernise the world's longest reigning monarchy.

Now 15 years into his reign, Emperor Akihito is considered to have more liberal and forward-thinking views than his father, the wartime emperor Hirohito.