Exact Sciences Explains: Prognostic vs Predictive

Many patients struggle to understand the clinical language of cancer care. Having to interpret endless acronyms and complicated medical terms can make a difficult experience even harder. However, learning key words can empower patients to advocate for themselves and make more informed decisions about their treatment. Two important — and easily confused — terms worth understanding are prognostic and predictive.

What is the difference between a prognostic and a predictive test?

Although the terms might seem similar, prognostic and predictive tests deliver very different information. Prognostic tests provide insight into how a patient’s cancer may behave over time, such as the likelihood it will return. Predictive tests help to determine whether a patient is likely to benefit from a specific therapy, like chemotherapy.1

How do prognostic and predictive tests work?

Prognostic and predictive tests look for the presence of specific biomarkers to help physicians learn more about a patient’s cancer. Prognostic biomarkers provide information about how the cancer might progress or return, and predictive biomarkers to help physicians determine whether a specific therapy may help. Only a few factors are proven to predict a cancer’s response to treatment.1

Why does prediction matter?

When a test can predict the benefit of a particular therapy, it can help to guide treatment choice and support more individualized care. Predictive tests, like the Oncotype DX Breast Recurrence Score^® test, give patients and physicians more confidence in their decision-making and, in some cases, may enable patients to choose to avoid potentially unnecessary chemotherapy2 and its associated costs.3

How does Exact Sciences use prognostic and predictive information to support personalized treatment?

Exact Sciences’ precision oncology tests work together to provide personalized information throughout a patient’s care. To find out how, let’s follow the journey of a fictional patient, Rita.*

Rita has a family history of cancer, so her doctor orders Exact Sciences’ Riskguard^® Hereditary Cancer test to learn more about her risk for the disease. The test looks for cancer-related genetic mutations in Rita’s DNA — and it finds them. Rita has an elevated risk of developing breast cancer. Empowered with this information, Rita’s care team adjusts her cancer screening plan. If Rita gets cancer, they want to catch it as early as possible.

A year later, Rita finds a lump in her breast; a biopsy confirms it’s cancer. Her cancer was tested with several biomarkers to see whether it is driven by estrogen. Because her cancer is found to have a biomarker called estrogen receptor, her oncologist orders the Oncotype DX Breast Recurrence Score^® test. The Oncotype DX^® test is a standard of care for guiding treatment in estrogen receptor-positive, HER2-negative early-stage breast cancer4-12 and the only test proven to be both prognostic of distant recurrence and predictive of chemotherapy benefit.4,5,13 Based on Rita’s Recurrence Score^® result, her Riskguard report, and other health information, Rita’s oncologist recommends surgery and then chemotherapy. Rita is nervous about going through chemotherapy, but she and her care team are confident that it is the right choice for her.

After Rita completes chemotherapy, everyone wants to know whether her cancer is gone. The Oncodetect^® test helps them find out. This molecular residual disease (MRD) test looks for tiny fragments of tumor DNA in Rita’s bloodstream, a sign that cancer may still be present or likely to come back.14-16,** Fortunately, the test finds no signs of cancer. Rita breathes a sigh of relief; and her care team, based on all they have learned, creates a post-chemotherapy plan, which includes an estrogen blocker, specifically for Rita — to maintain and monitor her health and preserve her peace of mind.

Our fictitious patient, Rita, caught her cancer early. For patients who are diagnosed with advanced solid tumor cancers (stage 3 and 4), Exact Sciences offers the OncoExTra^® test. This test uses information about a patient’s genes and their tumor’s genes to match the patient to therapies that may help.1717 If no approved treatments are available, the test report can help guide the patient to potentially relevant clinical trials.

The Riskguard, Oncotype DX, Oncodetect and OncoExTra tests help doctors create efficient, effective and personalized treatment plans. That’s the power of precision oncology.

What’s the takeaway?

The most important takeaway for patients: if you don’t understand something — like the difference between prognosis and prediction, or how different cancer tests can inform your treatment plan — ask. Your care team is there to explain your options and to help you make the best possible decisions for your health.