PGMs' role in the fight against cancer is twofold: as the active ingredient in chemotherapy drugs and in radio-active implants for radiation therapy (brachytherapy).

In the first of these, platinum compounds cisplatinum and carboplatinum have the unique quality of inhibiting the splitting and growth of cancerous cells. These compounds have been particularly successful in the treatment of testicular and ovarian cancers. More recently, palladium compounds have also been successfully tested.

In brachytherapy, implants are made of platinum with the active ingredient of iridium isotopes. These are placed directly into tumours, giving a high radiation dose to the tumour while reducing the effect on surrounding healthy tissue.