Large panel genomic tumor testing (also called somatic testing) is a promising technology that has the potential to improve care for many patients. However, this testing is not the best choice for all patients and some who have testing will not benefit from the results. Shared decision making can help patients make well-informed decisions that are consistent with their preferences and values.
Discussing the option of genomic tumor testing with cancer patients can be complex as this discussion often considers disease progression and current therapeutic options as well as the patient’s readiness to investigate a change in therapy and possibly, research participation.
The goal of this resource is to support clinicians when communicating with patients about the process, benefits, risks, and limitations of genomic tumor testing so they can make informed decisions about whether to undergo testing.
The primary goal of genomic tumor testing is to identify possible personalized (targeted) treatments for a patient’s cancer type. Genomic tumor testing is used to find DNA changes, or variants, that exist in cancer cells. Some of these variants may play a role in how the cancer grows, spreads, and responds to treatment. Therefore, genomic tumor test results can sometimes help clinicians choose the right medicines to treat a person’s cancer.
Genomic tumor testing (versus germline testing)
Logistics
The purpose of tumor testing is to identify possible personalized (targeted) treatments for the patient’s specific cancer. The results of genomic tumor testing may provide information on how a patient’s cancer is expected to act and may help determine how to treat the cancer. Tumor testing may identify treatments that may not be apparent based on existing pathology reports. In some situations, tumor testing can also provide information about prognosis.
Patients may ask how likely it is that tumor testing will identify a targeted treatment. This is a new area of medicine with varying rates of utility reported in different studies. Not all patients who have a variant identified will change management based on test results.
There are limited data supporting the therapeutic benefit of targeted treatments. Patients may receive a result that is uninformative because there is not a clear recommendation for treatment based on the results. It is important that clinicians discuss this limitation with patients to set realistic expectations.
In general, there are no physical risks of testing (other than those associated with a new biopsy, if indicated). However, due to the limitations discussed above, there is the risk of unrealistic expectations from the patient, resulting in disappointment, anxiety or distress after receiving tumor testing results. This is because the result may:
Targeted treatments may improve patient outcomes but are unlikely to cure cancer for most patients. Some patients may not respond at all or may respond favorably for a period of time before the tumor develops resistance and stops responding to the treatment.
Tumor testing could also identify a potential inherited genetic variant. In this case, additional evaluation and testing is often indicated. If an inherited genetic variant is found, the patient’s relatives may be at increased risk for cancer or other disease. While some patients may be distressed to learn this information, others may see this as a benefit of testing.
The personal values and experiences of cancer patients, and those of their family members, may influence decisions about tumor testing.
Communicating with patients about the decision to undergo genomic tumor testing is much like conversations in other areas of cancer care. Patient motivation, expectations and concerns, as well as psychological response to the cancer diagnosis and its treatment, will all play a role in decision making about genomic tumor testing. The provider’s counseling skills can be an effective facilitator of effective patient decision making. It can be helpful to follow the SHARE framework for shared decision making:
Step 1: Seek your patient’s engagement in the discussion about genomic tumor testing.
Step 2: Help your patient explore and compare options about whether or not to test and/or which test is best for the patient.
Step 3: Assess your patient's values and preferences.
Step 4: Reach a decision with your patient.
Step 5: Evaluate your patient's decision.
Talking to Cancer Patients about Genetic Testing. This video from MedPage today is part of the ASCO Clinical Pearls series.
The SHARE Approach – Essential Steps of Share Decisionmaking. This Guide from AHRQ presents a five-step process for shared decision making that can be applied across health care.
Exploring Cancer Biomarker Testing(CME | CNE). Learn about benefits, limitations, and challenges of using cancer biomarker testing.
Choosing the Best Genomic Tumor Test (CME | CNE). Learn about the benefits and limitations of different genomic tumor test options for patients with cancer and how to determine the best test for each patient.
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Chakravarty, D., Johnson, A., Sklar, J., et al. (2022). Somatic Genomic Testing in Patients With Metastatic or Advanced Cancer: ASCO Provisional Clinical Opinion . J Clin Oncol, 40(11), 1231-1258.
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This resource was developed as part of the Maine Cancer Genomics Initiative (MCGI) and is supported by The Harold Alfond Foundation and The Jackson Laboratory.
Reviewed May 2023