Chemotherapy began with a poison — indeed, one that had been used as an agent of chemical warfare — nitrogen mustard.

In the 1940s, two pharmacists working for the US Defence Department studied post-mortem examinations of soldiers exposed to mustard gas in the First World War and found that their lymphoid systems had been heavily suppressed. Therefore, they reasoned, the same poison might be used to kill lymph cancers, such as lymphoma. They injected it into a patient and saw a tumour shrink. Chemotherapy was born.

Yet its origins make plain that most chemotherapeutic agents were blunt instruments, toxins that killed healthy cells just as effectively as they killed cancer cells. Their side-effects were unpleasant and justified only by the fact that the alternative was death.

Chemo has a bad image, but its successes should not be ignored. It can cure testicular cancer, Hodgkin’s disease, non-Hodgkin’s lymphoma and some leukaemias. When used after surgery and radiotherapy, it can reduce the risk of recurrence in breast, colon and lung cancers, among others.

The commonest side-effects are nausea, fatigue, mouth sores, nerve damage, diarrhoea, hair loss and a greater risk of infections. It’s a tough experience, but big improvements in the drugs, how they are delivered and better management of the side-effects have transformed chemo in the past 20 years.

New drugs to prevent nausea, the prototype of which was odansetron, have helped enormously. So have techniques such as in-dwelling intravenous catheters, used to deliver drugs more accurately.

Complementary therapies also have a role. While it is easy to mock aromatherapy, acupuncture and massage as unproven, they often help people through the discomforts of chemo. Relaxation techniques help, and so, too, do better drugs and better targeting. A drug such as Glivec, which has made a huge difference to the treatment of several cancers, targets the cancer so precisely that it has many fewer side-effects.

Most new cancer therapies fall into this category, while monoclonal antibodies can be used to carry the chemotherapy drugs precisely to where they are needed, avoiding collateral damage — but they are pricey. Other drugs that once needed hospital treatment are being replaced by smart pills, such as Xeloda for gastrointestinal cancers, taken orally.

Even if such drugs cannot convince the National Institute for Health and Clinical Excellence that they get better results, they are so much easier to take that it makes the experience for patients much less burdensome. Nobody claims that chemotherapy is a picnic, even today. Some sail through it relatively unaffected, others suffer much more, but, thanks to a legion of developments, it does not carry the horror that once it did.

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