Lama Zopa Rinpoche gave this advice on how to think when diagnosed with cancer. When we experience the cancer for the sake of all sentient beings we collect skies of merit and it brings us closer to enlightenment.
Days 1-3: Maitreya Buddha puja, teachings and meditation on Maitreya Buddha, and oral transmissions of the Maitreya mantra, Maitreya prayer and King of Prayers
A student wrote to Rinpoche asking for practices for the rest of his life. Rinpoche responded with this advice.