If you are searching for a textbook with quality standards for oncology pharmacy services, ESOP - European Society of Oncology Pharmacy - http://www.esop.li/index.html is the place where you have to search.
QuapoS, developed by German oncology pharmacists in both hospital and public pharmacies as members of the DGOP (German Society for Oncology Pharmacy), is the textbook you need, and you can download it from the link
http://www.esop.li/countries/nationalsites.html
Quapos3 has been translated in many languages and you can download the .pdf you prefer.