Breast cancer test may stop un-needed therapy
“New breast cancer test could spare women chemotherapy,” is the reassuring news in The Guardian.
The new test, called Oncotype DX, is used after surgery for breast cancer. The test works by looking at how active certain genes are in the tumour. Levels of gene activity should help predict whether the tumour is likely to recur.
The test has now been recommended by NICE for people with a certain type of early breast cancer – specifically the oestrogen receptor positive (ER+) and human epidermal growth factor receptor 2 negative (HER2-) types of breast cancers. These are cancers that are associated with specific hormones.
People in these risk groups may find it particularly difficult to judge how the potential benefits of chemotherapy weigh up against its side effects, such as fatigue, nausea and hair loss.
Hopefully this new test will give people and their doctors more information on their risk of having a breast cancer recurrence, leading to more women being able to make an informed decision about how they wish to proceed with their treatment.
NICE does not suggest that this will lead to fewer people receiving chemotherapy, only that chemotherapy will be better targeted to those who need it.
What is the issue?
Breast cancer is the most commonly diagnosed cancer in women in England and Wales. Breast cancer survival rates have improved over the last two decades and two out of three women with the condition survive beyond 20 years. However, it remains the second biggest cause of cancer death in women after lung cancer.
If breast cancer is detected early, the usual treatment is to remove the tumour surgically. Once the tumour has been removed further treatment may be required, depending on whether the cancer has a low, intermediate or high risk of returning.
The likelihood of the cancer returning is based on several factors, including the size and “grade” of the tumour (how advanced the cells are), and whether it has spread locally to the lymph nodes. The options for treatment after surgery include hormone therapy, chemotherapy or radiotherapy.
The decision as to whether to have further chemotherapy – which can cause considerable distress and side effects such as nausea and vomiting, fatigue and hair loss – can be a difficult one. This is a particularly difficult decision for women who fall into the “intermediate” risk group as it is uncertain whether the potential risk of recurrence of cancer justifies the downsides associated with chemotherapy.
Current NICE cancer guidelines recommend that people at intermediate and high risk are offered chemotherapy. However, this may be unnecessary for some people in the intermediate group, but this has been hard to predict.
Four new tests, Oncotype DX and three other similar tests, were assessed by NICE to see whether they could provide additional information that will help to predict the likelihood of recurrence and improve outcomes for women with breast cancer.
What are NICE recommending?
NICE has evaluated four new tests, which are carried out on the tissue of early breast tumours after they have been surgically removed. These are:
- the Oncotype DX test
- the MammaPrint test
- the IHC4 test
- the Mammostrat test
These tests measure the activity of certain genes within the tumour cells to help predict how fast the tumour is likely to grow and whether it is likely to spread.
NICE has recommended one of them, Oncotype DX, as an option to help build up a picture of the likelihood of recurrence of early breast cancer in people who are currently judged to be at intermediate risk, and who have tumours that have a specific set of characteristics.
The test results would help in the shared decision of whether to have chemotherapy after the breast tumour is removed.
NICE has concluded that the evidence about the other three tests is less conclusive about their potential benefits. NICE has therefore said that they should not be available for widespread use in the NHS. However, they can still be used in research to assess their potential benefits.
How reliable is the test?
NICE judged that the Oncotype DX test could add value in predicting risk of breast cancer recurrence if it is used in addition to the other factors that can help predict recurrence such as size and grade of the tumour and family history.
However, even with the new test it is not possible to predict with 100% certainty whether a woman’s breast cancer will recur.
NICE also recommends that ongoing evidence is collected on how well the test predicts recurrence. And NICE says that the test does not predict how a patient will respond to chemotherapy.
How does this change current practice?
The new test will give doctors an extra tool that they can use to predict recurrence, alongside existing methods.
Not all people with breast cancer would be eligible for this test. This test has been recommended to be used only for people with early breast cancer and they have to be:
- judged to be at intermediate risk of recurrence using currently available techniques
- to have cancer that has not spread to their lymph nodes
- to have a tumour that is oestrogen receptor positive (ER+) and human epidermal growth factor receptor 2 negative (HER2-)
Other factors will still be used to help guide decisions about whether or not to have chemotherapy after surgery, but it should help to identify the patient more likely to have a recurrence.
It is fair to say that it is not clear what the effect on the overall percentage of patients having chemotherapy is at this moment in time. But better targeting of chemotherapy – giving it to those who are more likely to benefit from it – may also help women avoid unnecessary treatment and potential harm.
The test may also help to alleviate some of the emotional and psychological strain experienced by patients who are currently placed in the “intermediate” risk category.