JOHANNESBURG (AP) — South African retired Archbishop Desmond Tutu has canceled travel plans for the rest of the year so he can undergo new treatment for prostate cancer, a foundation said.

The Desmond and Leah Tutu Legacy Foundation said in a statement Tuesday that the Nobel Peace Prize laureate is starting a new course of medication to manage "the prostate cancer he's been living with for the past 15 years."

Tutu's daughter and the foundation's director, Mpho Tutu, said her 83-year-old father had planned to attend a meeting of Nobel Peace Prize laureates in Rome this week.

The meeting was shifted to Rome after the Nobel laureates suspended plans to hold their annual meeting in South Africa because they said the government there refused to grant a visa to the Dalai Lama, the Tibetan Buddhist spiritual leader. The South African government had said the Dalai Lama canceled his planned visit while South Africa's diplomats in New Delhi were processing his visa application.