Virtually any therapeutic method can, in principle, be combined with another. The decision on this issue depends on whether the achievable increase in therapeutic effect is justified by the additional side effects.

The aim and purpose of the local procedures (radiation, operation, etc.) is generally to remove the majority of the tumour cells without leading to the build-up of resistance. Systemic treatment (i.e. chemotherapy) is directed against all tumour cells which cannot be targeted using local methods, in particular metastases. Chemotherapy carried out in parallel with radiation may also increase the radiation sensitivity of some cancer cells.

It is one of the functions of the Tumour Board to organize and coordinate such combination treatments, which are then carried out in parallel by the various specialists.