Amid the growing armoury of new and developing therapies, the two founding staples of modern cancer care, radiotherapy and chemotherapy, remain widely in use. However, they have also advanced considerably in recent years, improving their efficacy and reducing side-effects.

About four in ten cancer patients have radiotherapy as part of their treatment. It can be given from outside the body as external radiotherapy using X-rays, cobalt irradiation, electrons and more rarely, other particles such as protons, to attack cancer cells.

It can also be given from within as internal radiotherapy, or brachytherapy, by placing radioactive material in or close to the tumour being treated. This is increasingly popular with prostate cancer.

Radiotherapy destroys the cancer cells in the treated area. Although normal cells are also affected by radiation, they are better at repairing themselves than the cancer cells. Radiotherapy may be used to destroy a tumour, to shrink it for surgery or to relieve pain.

One new approach, currently being trialled for breast cancer and cancer of the head and neck, is intensity modulated radiotherapy (IMRT), which shapes the radiation beams to closely fit the shape of the cancer. But it also alters the radiotherapy dose, according to the shape of the cancer. This means that the central part of the cancer receives the highest dose of radiotherapy and a surrounding area of tissue gets lower doses.

Other teams are investigating different timings and dosages to see if they work better for various cancers.

In hyperfractionated radiotherapy, patients receive more than one treatment per day, while hypofractionated radiotherapy involves giving larger doses of radiotherapy per treatment, but giving fewer treatments.

The other long-standing therapy type, chemotherapy, involves treatment with drugs that are toxic to body cells that are growing and dividing.

Cancer cells grow and divide more often than normal cells, so are more at risk from this type of treatment. Testicular cancer and Hodgkin’s lymphoma respond particularly well to chemotherapy.

The first chemotherapy drugs to be used clinically, in the late 1940s, were based on a poisonous gas called nitrogen mustard. Nowadays, about 60 different cytotoxic drugs are currently available, with new ones being developed constantly. One drug, or a cocktail of many, may be used.

Chemotherapy damages the genes inside the nucleus of cells. Some drugs damage cells at the point of splitting. Some damage them while they are busy making copies of all their genes before they split.

Cells that are at rest (most normal cells, for instance) are much less vulnerable to chemo damage. But nevertheless, it affects healthy body tissues that grow all the time, such as the skin, hair and digestive system, which explains why nausea and hair loss are common side-effects.

Normal cells can repair damage more quickly than cancer cells. So the damage to healthy cells does not usually last. Most side-effects disappear once treatment ends.

Explore Related Features

• Young Photographer