Should You Consider Genetic Testing for Cancer? 10 Reasons to Talk to a Genetic Counselor

By Amanda Shrewsbury, MS, CGC

Genetic testing for cancer used to be reserved for people with the most striking family histories. That's no longer the case. Testing has become more affordable, more comprehensive, and more accessible, and the reasons to consider it have expanded along with the technology.

Some reasons are clinical red flags that meet established medical criteria for testing. Others are proactive — reflecting a growing recognition that knowing your genetic risk profile is a powerful tool for prevention, screening, and longevity planning. Both are valid.

Here are 10 reasons you might consider talking to a genetic counselor.

1. You Were Diagnosed with Cancer Before Age 50

Cancer that develops at younger ages is one of the strongest signals of a possible hereditary cause. The general lifetime risk of cancer is heavily skewed toward older ages — colorectal cancer, breast cancer, and prostate cancer are far more common after 60 than before 50. When cancer appears earlier than expected, a hereditary syndrome may be involved.

NCCN guidelines recommend considering genetic testing for any cancer diagnosed before age 50, and for some cancers (like prostate cancer), the threshold is 55 (NCCN, 2026). If you or a close relative was diagnosed at a young age, that alone may be a reason to pursue testing.

2. You Have Had More Than One Primary Cancer

If you've been diagnosed with two or more separate primary cancers (not metastases or recurrences of the same cancer), that's another red flag. Multiple primary cancers in one person — for example, breast cancer and ovarian cancer, or colorectal cancer and endometrial cancer — significantly raises the likelihood that a hereditary syndrome is at play.

This is especially true if the cancers fit a known pattern, such as the breast/ovarian/pancreatic cluster associated with BRCA1 and BRCA2, or the colorectal/endometrial cluster associated with Lynch syndrome.

3. You or a Family Member Has Had a Rare Cancer

Some cancers are uncommon enough that even one diagnosis warrants genetic evaluation. These include:

Ovarian cancer (any age)
Pancreatic cancer (any age)
Male breast cancer (any age)
Triple-negative breast cancer diagnosed at any age
Metastatic, intraductal, or high-Gleason prostate cancer
Medullary thyroid cancer
Adrenocortical carcinoma
Sarcoma

Any of these on your personal or family history is reason enough to talk to a genetic counselor, regardless of how many other relatives have had cancer (NCCN, 2025; NCCN, 2026).

4. Multiple Relatives on the Same Side of the Family Have Had Cancer

This is the family history pattern most people think of first. Multiple relatives on one side of the family — your mother's side or your father's side, not both — with the same cancer or related cancers can suggest an inherited predisposition.

Pay particular attention to:

Three or more relatives on the same side with the same cancer
Multiple relatives with related cancers (e.g., breast and ovarian, or colorectal and endometrial)
Cancers across multiple generations

For a deeper dive on family history patterns, see: What Your Family Tree Might Be Telling You About Cancer Risk.

5. A Family Member Has Tested Positive for a Hereditary Cancer Variant

If a first-degree relative (parent, sibling, or child) has been identified as carrying a pathogenic variant in a known cancer gene, you may have up to a 50% chance of carrying the same variant. This is called cascade testing, and it's one of the highest-yield reasons to pursue testing because the lab is looking for a single, known variant rather than searching across thousands of possibilities.

Cascade testing is also typically the most affordable, since insurance generally covers it when there's a documented family variant. (For more on how to navigate this conversation, see: How to Talk to Your Family About Genetic Testing.)

6. You Have Ashkenazi Jewish Ancestry

People of Ashkenazi Jewish descent have a higher carrier frequency for certain BRCA1 and BRCA2 variants — about 1 in 40 individuals, compared to 1 in 400 in the general population (NCI, 2024). Three specific founder variants account for the majority of BRCA-related cancer in this population.

Other ancestral groups also have higher frequencies of specific hereditary cancer variants, including some Hispanic, French Canadian, Icelandic, and Polish populations. If you have one of these ancestries, especially in combination with any cancer family history, genetic testing may be appropriate even without other red flags.

7. You're Already Living with Cancer and Want to Inform Your Treatment

Genetic testing isn't just about understanding future cancer risk — it can also directly affect treatment decisions if you've already been diagnosed. Targeted therapies like PARP inhibitors are specifically designed for cancers driven by BRCA and certain other genes. Immunotherapy responsiveness can be predicted in part by Lynch syndrome status. Radiation sensitivity is influenced by certain inherited variants.

If you've recently been diagnosed with cancer, genetic testing can help your oncologist make more informed treatment recommendations. This is one of the fastest-growing reasons people pursue testing today.

8. You Want to Take Control of Your Health with Complete Information

Some people pursue genetic testing not because of a specific family history red flag, but because they want a comprehensive understanding of their hereditary risk profile. They believe knowledge is power, and they want to make informed decisions about screening, prevention, and lifestyle.

This is a legitimate and increasingly common reason to test. About 10% of all cancers are hereditary (NCI, 2024), and many people who carry pathogenic variants don't have the obvious family history pattern that typically prompts a referral. If you're someone who values being proactive about your health, genetic testing can give you information that fundamentally changes your screening plan.

9. You're Investing in Longevity

The longevity movement has changed how many people think about preventive health. If you're already optimizing for longevity through advanced lipid panels, continuous glucose monitoring, fitness tracking, regular bloodwork, and other health metrics, hereditary cancer testing is one of the highest-leverage things you can add to that picture.

Knowing your hereditary cancer risk profile can dramatically change your screening calendar. A BRCA2 carrier might begin breast MRI at 25 instead of mammography at 40. A Lynch syndrome carrier might start colonoscopy at 20–25 with annual surveillance, rather than at 45 with a 10-year interval. These differences aren't just statistical — they translate into cancers caught at earlier stages, when they're far more treatable.

For people committed to evidence-based longevity, this is a one-time test with lifelong implications.

10. You're Planning a Family

Some hereditary cancer variants can be passed to children, and family planning decisions may be influenced by genetic test results. Knowing your status before pregnancy gives you and your partner more time to consider options like preimplantation genetic testing (PGT) if relevant. It also gives you information that may affect screening decisions for your children later in life.

This is especially worth considering if you have a family history of pediatric or young-adult cancers, or any of the other red flags listed above.

Reasons Beyond This List

The 10 reasons above cover the most common scenarios, but they're not exhaustive. Some people pursue testing because of a known cancer cluster in a community or workplace. Some test because they've taken a direct-to-consumer test and want clinical-grade follow-up. Some test because they want to understand a long-deceased relative's cancer history. Whatever the reason, a pre-test genetic counseling session is the right place to start.

If you're not sure whether your situation warrants testing, that's exactly the kind of question a genetic counselor can answer in an appointment. There are no wrong reasons to ask.

Have a question? Reach out anytime:

Email: hello@clearpathgenetics.com
Text or call: +1 (720) 799-0730

References

National Comprehensive Cancer Network. (2026). Genetic/familial high-risk assessment: Breast, ovarian, pancreatic, and prostate (Version 3.2026). https://www.nccn.org

National Comprehensive Cancer Network. (2025). Genetic/familial high-risk assessment: Colorectal, endometrial, and gastric (Version 1.2025). https://www.nccn.org

National Cancer Institute. (2024). BRCA gene changes: Cancer risk and genetic testing fact sheet. https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet

National Society of Genetic Counselors. (2024). Hereditary cancer screening and testing referral guide. https://www.nsgc.org

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