There are some useful new apps out which you should take a look at.
ONCOassist This app includes a number of excellent resources. They include calculators for GFR and MASCC score, tools for calculating the benefit of adjuvant treatment, CTCAE v4.0, and AJCC staging. It requires a paid subscription but new features are added fairly regularly.
Acute Oncology Clinical Guidelines Produced by the London Cancer Alliance this app includes comprehensive guidelines for managing many complications of cancer and its treatment, such as hypercalcaemia and extravasation of chemotherapy.
Cancer Care Ontario have produced three free apps - a comprehensive drug formulary, symptom managment advice, and cervical screening guidelines.
NCCN Guidelines from the US. The app presents these excellent guidelines in a format optimised for mobile devices.
ESMO Guidelines European cancer management guidelines for most tumour types. Useful educational and practice resource.
Cancer Emegency Response Tool Provides advice for patients with side-effects of cancer therapy. Consider recommending it to your patients.