Could you tell me what are cancer treatment options when the patient also has Parkinson's disease?

Cancer is primary. Usually cancer is more immediate medical problem than parkinson disease, so just about any treatment options are on the table. You do want to avoid certain nausea medicines, especially Reglan (metoclopramide), compazine, and phenergan, (promethazine) as these can greatly exacerbate parkinson disease, especially the first two. Otherwise most cancer agents are acceptable in parkinson disease.