RanDx an affordable highly sensitive predictive test for breast cancer recurrence and metastasis

Breast cancer is the most commonly diagnosed cancer in the UK with ~1,000 women dying/month from secondary/metastatic breast cancer; this is when the cancer has spread and can be controlled but not cured.

Breast cancers are sub-typed by the presence or absence of hormone receptors (HR; oestrogen, progesterone) and HER2 receptors; the commonest sub-type is HR+ve, HER2-ve (70% of breast cancers). When women are first diagnosed with HR+ve, HER2-ve breast cancer, initial treatment is usually with surgery +/- radiotherapy. Doctors then estimate each patient's risk of developing metastatic cancer in the future. Many are recommended to have drug treatment, with "adjuvant" endocrine therapy, which reduces the risk of the cancer coming back. Higher risk patients are also recommended to receive chemotherapy, further reducing the risk of their cancer returning. Chemotherapy has, however, unpleasant side effects and not all patients benefit.

NHS doctors can request the "Oncotype DX" test, which looks at the genes in a patient's breast cancer and identifies those women most at future risk of developing metastases and more likely to benefit from chemotherapy.

Oncotype Dx, the "gold standard" test, is complicated and expensive; the cancer sample are sent to a specialist laboratory abroad, which can lead to delays in treatment. Oncotype Dx is available to UK and NHS patients, but not for women in many low/middle income countries because of its cost.

We have developed RanDx, a new test that is easier, quicker and less expensive than Oncotype Dx because it can be rapidly performed using existing equipment in NHS pathology laboratories. The RanDx test could save the NHS ~£65m/year and make testing more cost-effective in the UK and accessible to patients in many more countries.

We have already shown that RanDx distinguishes between women at high and low risk of later developing metastatic disease. Now we need to test whether RanDx and Oncotype Dx give equivalent results, so that RanDx can replace Oncotype Dx.

To do this we will identify 600 patients whose breast cancers already have had the Oncotype Dx test and re-test their original tumour samples using RanDx. This will give us an Oncotype Dx and RanDx score for each patient that we can compare. If the scores are equivalent, we will implement ways to manufacture the RanDx test kit for widespread use. We will then be ready to submit the RanDx for inspection/regulatory approval, after which it could be used in routine care.