Hello,
I am a practitioner in complementary medicine and work exclusively with all stages of cancer. I would not suggest deep tissue massage as it is likely to make the receiver uncomfortable. We always suggest if massage can be tolerated to have a gentle or light massage and avoiding any recent scar tissue or tumor areas. Otherwise massage has been very successful anecdotally and with research for use with oncology patients and those in pallative care including reflexology, cranial of gentle head massage and the use of aromatherapy. Some essential oils have proved successful in research for cancer patients providing relaxation and in very rare cases reducing tumors.
The benefit of the comfort of the person with cancer is paramount and gentle massage will do no harm as it will provide other benefits and will not spread cancer.