Complementary therapies: what helps, and what to avoid

Wanting to do something yourself, after months of things being done to you, is one of the most understandable impulses after cancer treatment. Some of what is on offer genuinely helps with symptoms and wellbeing. Some of it is inert and expensive. A small part of it is dangerous, either through interactions or by persuading people to delay treatment that works. This page is about telling those apart.

The distinction is not pedantry. Research comparing people who chose alternative medicine instead of conventional treatment for curable cancers with those who had conventional treatment found substantially worse survival in the alternative group. Adding something is a different decision from replacing something.

• Exercise — the strongest evidence of anything in this space, for fatigue, mood and function. See exercise after cancer.
• Mindfulness-based programmes — for anxiety, depression and quality of life, including fear of recurrence.
• Yoga and tai chi — for fatigue, sleep and wellbeing, with the added benefit of being physical activity.
• Acupuncture — studied for hot flushes, joint pain on aromatase inhibitors, and nausea; results are mixed but it is offered in many cancer services for symptom relief.
• Massage and reflexology — for relaxation and short-term anxiety; ask for a therapist experienced in oncology, particularly with lymphoedema or bone metastases.
• Psychological therapies — not usually thought of as complementary, and the best-evidenced option for distress. See mental health after cancer.

• St John’s wort affects the metabolism of many cancer drugs and can make them less effective. It is the clearest example, not the only one.
• High-dose antioxidant supplements during radiotherapy or some chemotherapy are questioned — discuss before taking them.
• Grapefruit and grapefruit juice affect several drug pathways.
• Some herbal products have oestrogenic effects, which matters after hormone-receptor-positive cancers.
• High-dose vitamins and minerals are not harmless — vitamin D, calcium, iron and B12 are best taken for a specific indication rather than generally.
• Tell your oncology team and your pharmacist everything you take. They are not going to disapprove; they are going to check the interactions.

A reasonable practitioner will ask about your medical treatment, be willing to write to your team, describe what their therapy can and cannot do, and be registered with a professional body you can look up.

People often hide complementary therapy use from oncologists, expecting disapproval. That is the one outcome worth avoiding, because it removes the chance to catch an interaction. A neutral opening works: "I am thinking about trying X — is there anything about it that would interact with my treatment?"

Many cancer support centres offer therapies such as massage, mindfulness and relaxation free of charge, delivered by people trained to work with cancer patients. That is usually a better starting point than a private clinic.