The Chaplet to St. Peregrine is prayed on a nine bead chaplet, with a medal of St. Peregrine on one end, and a crucifix on the other. It is a powerful chaplet for those who are fighting cancer, to give them strength and hope.
Chaplet to St. Peregrine
Introductory prayer on the crucifix:
O God, who gave to St. Peregrine an angel for his companion, the Mother of God for his teacher, and Jesus as the physician for his malady, grant we beseech you through his merits, that we may on earth intensely love our holy Angels, the Blessed Virgin Mary, and our Saviour; and in Him bless them forever. Grant that we may receive the favour which we now petition: (present your request). We ask this through the same Christ our Lord. Amen.
On each bead pray:
One our Father, one Hail Mary, one Glory Be, and 'St. Peregrine, pray for us'.
To learn more about St. Peregrine, the following book looks pretty good - I haven't read it yet, but will be adding it to my reading pile. It explains who St. Peregrine was, tells about miracles associated with him, and also includes prayers and devotions to this powerful saint.