New test could reveal chemotherapy benefit in 24 hours

Scientists have developed a new test to indicate whether the most commonly-used chemotherapy drug will benefit a breast cancer patient within 24 hours of taking it. The test also identifies patients who may benefit from PARP inhibitors, a promising new class of cancer treatment.

27 Aug

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The work was carried out at the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR) in London with the results published today (Friday 27 August) in the journal, Clinical Cancer Research. The test has the potential to identify which patients benefit from anthracycline chemotherapy, a standard treatment for many of the 46,000 women diagnosed with breast cancer in the UK each year.

The team looked at the protein RAD51, which plays a major role in DNA repair. Studying 68 breast cancer patients, they found that if this protein did not work in cancer cells, patients were much more likely to respond to anthracycline. Many of these patients had a complete response with the tumour disappearing from the breast. If the DNA repair process was working in the tumour, they would probably not respond to the treatment, with complete response being unlikely.

This is the first time this mechanism has been shown in a clinical setting and could have important implications for patients.

Lead author Dr Nicholas Turner, from the Breakthrough Breast Cancer Research Centre at the ICR, said: “This test may reduce the time taken to discover if a breast cancer patient is not going to have a good response to a chemotherapy from three months to just 24 hours. It would make a big difference to patients, who could be moved onto other treatment options sooner ” and spared unnecessary side effects.

“This test is at an early stage of development and now needs to be confirmed in larger studies to see if it can be effective.”

Excitingly, this research also suggests that patients who are also likely to respond to PARP inhibitors could be identified. Recent studies have suggested that up to 30 per cent of breast cancer patients could be treated with PARP inhibitors – although the drugs are still in clinical trials and not yet licensed for use. This or similar tests could be very helpful in accelerating the development of these drugs.

Professor Alan Ashworth, Director of the Breakthrough Breast Cancer Research Centre at the ICR, said: “We want to see all breast cancer patients get the right treatment at the earliest possible stage. This test is a step towards that aim and we now want to develop it so that it can be used routinely in the clinic. It is also exciting because it suggests a way of finding patients that might respond to PARP inhibitors.”

Currently, patients have to take a full 12-week course of chemotherapy before doctors know how well they have responded, which is typically a combination of two or three chemotherapy drugs. One of these would usually be anthracycline. While the drug works for many patients, some patients do not respond. If a woman does not respond to anthracycline based chemotherapy they could be taken off it and treated with other chemotherapy drugs, or potentially switched to hormone therapies, such as tamoxifen.