Tumour profiling tests to guide adjuvant chemotherapy decisions in lymph node-positive early breast cancer

Not all people with early breast cancer will benefit from adjuvant chemotherapy. Decisions on chemotherapy use may be made based on clinical or pathological factors, or using a tool such as Predict or the Nottingham Prognostic Index, in combination with the personal preferences of the person with breast cancer. Additionally, tumour profiling tests may be used.

Tumour profiling tests are designed to provide information on the expression of genes in tumour samples from people with early breast cancer. The test results provide a risk profile of an individual's breast cancer. This can be combined with other clinical risk factors, such as nodal status and tumour size, to better predict the risk of disease recurrence in the future. Some tests may also predict how beneficial chemotherapy may be for the person.

NICE's guidance on tumour profiling tests to guide adjuvant chemotherapy decisions in early breast cancer (DG34) provides recommendations on using the tests for people with ER-positive, HER2‑negative and lymph node (LN)-negative (including micrometastatic disease) early breast cancer.

Tumour profiling tests could also be used to help guide decisions on adjuvant chemotherapy for people with ER- or PR-positive, HER2‑negative early breast cancer with 1 to 3 positive lymph nodes. This group has a clinically higher risk than people with LN-negative cancer. So, people with LN-positive cancer are more likely to have adjuvant chemotherapy recommended. Identifying people who may not benefit from adjuvant chemotherapy could allow them to avoid unnecessary treatment, and so avoid side effects and other impacts on day-to-day life associated with chemotherapy. Alternatively, testing could identify people who would be considered to have a low risk of disease recurrence based on clinical factors, but who would actually benefit from chemotherapy.

EndoPredict is a CE-marked assay that is designed to predict the likelihood of distant recurrence within 10 years of an initial diagnosis of breast cancer, as well as the benefit of chemotherapy. The test is for pre- and postmenopausal people with early breast cancer that is:

• ER-positive

• HER2-negative

• LN-negative or LN-positive (up to 3 positive nodes).

EndoPredict measures the expression of 12 genes: 3 proliferation-associated genes, 5 hormone receptor-associated genes, 3 reference (normalisation) genes and 1 control gene. This information is used to calculate a 12-gene molecular score (EP score).

EndoPredict uses RNA extracted from formalin-fixed, paraffin-embedded (FFPE) breast cancer tissue samples. The test can be done in local laboratories. Test results are available about 3 to 5 days after the sample has arrived at the laboratory.

The test process uses reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Online evaluation software (EndoPredict Report Generator) performs a quality check and calculates the EPclin score, which is the final test result. The EPclin score is calculated using clinical data about tumour size and nodal status, and the EP score. This can be used to estimate the likelihood of distant recurrence, assuming 5 years of endocrine therapy. An EPclin score below 3.3 indicates low risk of distant recurrence in the next 10 years (less than 10%). An EPclin score of 3.3 or more indicates high risk of distant recurrence in the next 10 years. The company claimed that the EPclin score can also be used to estimate chemotherapy benefit, in which people with an EPclin score below 3.3 are less likely to benefit from adjuvant chemotherapy.

MammaPrint is a CE-marked microarray that is designed to assess the risk of distant recurrence within 10 years and whether a person would benefit from chemotherapy. The test is for pre- and postmenopausal people with primary stage 1 or 2, or operable stage 3, breast cancer with the following clinical features:

• ER- or PR- positive

• HER2-negative

• tumour size less than or equal to 5 cm

• LN-negative or LN-positive (up to 3 positive nodes).

MammaPrint measures the expression of 70 cancer-related genes and 465 control genes.

The MammaPrint test is offered as an off-site service. In the UK, samples are sent for analysis at the Agendia laboratory in the US. A decentralised version of the test is also available for local laboratories with next-generation sequencing capability. The test requires a FFPE breast cancer tissue sample.

The test is based on diagnostic microarray. Software calculates the MammaPrint result on a scale of −1 to +1. The result indicates the risk of developing distant metastases over the next 10 years without any adjuvant endocrine therapy or chemotherapy. A MammaPrint result of 0 or below indicates high risk of metastases in the next 10 years and a result above 0 indicates low risk (10% or less) of metastases in the next 10 years. A result above 0.355 indicates ultra-low risk, which the company defines as more than 99% breast cancer-specific survival at 8 years and 97% breast cancer-specific survival at 20 years with 2 to 5 years of tamoxifen treatment. The company states that test results are typically reported within 10 days of receiving the sample at the laboratory and the average turnaround time is less than 5 days.

Oncotype DX is a CE-marked assay designed to quantify the 9-year risk of distant recurrence and predict the likelihood of chemotherapy benefit. The test also reports the underlying tumour biology: ER, PR and HER2 status. The test is intended for pre- or postmenopausal people with early breast cancer that is:

• ER- or PR-positive

• HER2-negative

• LN-negative or LN-positive (up to 3 positive nodes).

Oncotype DX quantifies the expression of 21 genes. Of these, 16 are cancer-related genes correlated with distant recurrence-free survival, and 5 are reference genes for normalising the expression of the cancer-related genes. This information is used to calculate the Oncotype DX Breast Recurrence Score.

Oncotype DX is offered as a test service to the NHS. Samples are processed centrally at the Exact Sciences laboratory in the US, which is accredited by the American Association for Laboratory Accreditation and the College of American Pathologists. The test requires a FFPE breast cancer tissue sample, which can be sent as a paraffin-embedded block or as 15 unstained charged slides. The test process uses RT-qPCR.

The test gives an Oncotype DX Breast Recurrence Score of between 0 and 100, which is used to estimate the 9-year risk of distant recurrence, assuming 5 years of hormonal therapy. The company states that the recurrence score also estimates chemotherapy benefit (in terms of reducing risk of distant recurrence). For LN-positive cancer (1 to 3 positive nodes), the instructions for use state that a score:

• below 18 predicts little to no chemotherapy benefit

• between 18 and 30 predicts a potential chemotherapy benefit

• of 31 or above predicts a large chemotherapy benefit.
  
  However, the company states that a cutoff of 25 should be used instead, in which a recurrence score of 25 or below predicts no chemotherapy benefit for postmenopausal women and 2.9% benefit at 5 years for premenopausal women. In both groups, a score of 26 to 100 is stated to predict substantial chemotherapy benefits.

The company states that Oncotype DX Breast Recurrence Score results are typically reported within 7 to 10 calendar days after the sample is received at the laboratory.

Prosigna is a CE-marked assay designed to provide information on breast cancer subtype and to predict distant recurrence-free survival at 10 years. The test is for postmenopausal women with early breast cancer that is:

• ER- or PR-positive

• HER2-negative or HER2-positive

• LN-negative or LN-positive (up to 3 positive nodes, or 4 or more positive nodes).

Prosigna measures the expression of 50 genes (PAM50) used for intrinsic subtype classification, 8 housekeeping genes used for signal normalisation, 6 positive controls, and 8 negative controls. The test uses RNA extracted from a FFPE breast cancer tissue sample, and can be done in local laboratories provided they have access to the NanoString nCounter Dx Analysis System. The company states that results are usually available within 3 days.

Prosigna classifies the risk of distant recurrence within 10 years, assuming 5 years of endocrine therapy, based on the PAM50 gene signature, breast cancer subtype, tumour size, nodal status and proliferation score (the proliferation score is determined by evaluating multiple genes associated with the proliferation pathway). The test gives an overall risk of recurrence score between 0 and 100. Based on this score and the nodal status, samples are classified into risk categories. For LN-positive cancer (up to 3 positive nodes), 0 to 15 indicates low risk, 16 to 40 intermediate risk, and 41 to 100 high risk. For 4 or more positive nodes, any score is assigned high risk. Clinical advice is that most people with 4 or more positive nodes would be offered chemotherapy under standard care.