I am a physiotherapist, and I used to work at a cancer resource centre, offering counselling and various therapies to clients before, during and after cancer treatment.
I agree that you should get consent from your oncologist, and I agree that gentle hands-on treatment is safe and promotes your wellbeing, so that would include various forms of massage, reflexology, reiki.
Acupuncture can be very helpful in treating muscle tension/pain as well as nausea, hot flushes and other side effects.
In the cycle between treatments, when you have low energy, it is important not to overdo things, so any treatment should promote rest and relaxation, but only when you have some energy, then gentle exercise and/or stretching is also beneficial to boost your immune system, improve circulation, and stimulate endorphins.
Happy to answer questions if you have any more.