Science correspondent James Wilkinson: "It doesn't mean patients will automaticaly be given chemotherapy"

Currently, most women who are diagnosed with the disease while it is still in its early stages have the cancerous lump surgically removed.

They only receive strong anti-cancer drugs in a treatment called chemotherapy if their doctor finds evidence that the cancer has spread to other parts of the body.

Benefits

Now an evaluation of research involving 18,000 women has concluded that polychemotherapy, a cocktail of chemotherapy drugs, could benefit all patients.

The study showed that in women under 50 in whom disease had not apparently spread, chemotherapy resulted in a 7% drop in deaths.

For women aged 50 to 69, there were 2% fewer deaths.

The report's authors say this is significant as women over 50 have previously been thought unlikely to benefit from polychemotherapy because of the strength of the drugs.

Side-effects

The Imperial Cancer Research Fund performed the research, which evaluated the findings of 47 different trials of chemotherapy treatment over 10 years.

Chemotherapy uses strong drugs

Chemotherapy has long been controversial.

Because cancer cells grow and divide rapidly, anti-cancer drugs are designed to kill fast-growing cells.

But some healthy cells also multiply quickly and chemotherapy can affect these cells, causing side-effects such as nausea, vomiting, hair loss and fatigue.

Professor Mike Richards of the Imperial Cancer Research Fund said: "There is no question of patients being forced to have chemotherapy.

"What doctors try to do is explain the advantages of chemotherapy and the downside because chemotherapy does have side-effects to women with breast cancer.

"Jointly the doctor and the patient together can come to the right decision as to what is right for the individual."

Lung cancer

Another study, published in the British Medical Journal, said many lung cancer patients would rather die quickly than suffer the harsh side-effects of chemotherapy.

It found that, although some patients would endure the treatment in exchange for one extra week of life, others did not want it even if meant living another two years.