Only a Small Fraction of Cancers Are Inherited. The Rest?

By Marji Keith and Chris Joseph

If you’ve ever thought, “Cancer runs in my family—so I guess it’s just a matter of time,” you’re not alone. We’ve heard that sentence countless times. We even thought it ourselves, before we learned the truth.

So here’s what might surprise you: Health studies for nearly 20 years have shown that only about five to 10 percent of cancers are actually hereditary.

The other 90 to 95 percent? They’re linked to things we can influence—diet, chronic inflammation, toxic exposure, stress, sedentary lifestyle, infections, poor sleep, and more. They’re linked to what we put in, on, and around our bodies, including what we eat, think, and who and what we surround ourselves with.

This is why our approach to dealing with cancer, cancer prevention, and recurrence is called The Metabolic Approach to Cancer.

The statistics that 90 to 95 percent of cancer is related to metabolic processes come straight from a landmark 2008 study called “Cancer Is a Preventable Disease that Requires Major Lifestyle Changes” by Anand et al., published in Pharmaceutical Research. (link to the study)

The authors broke it down clearly: cancer, in most cases, doesn’t come from your family tree—it comes from how you live and what you’re exposed to.

So Why Do We Still Believe Cancer Is Inherited?

There are a few reasons this myth persists:

First, we’ve been conditioned to believe it. This belief is so deeply embedded in our culture that questioning it feels radical—almost heretical. Think about it. How many times have you heard someone say, “My mom had breast cancer, so I’m getting my mammograms early”? Or “Colon cancer runs in my family, so I know I need to watch out for it”? It’s everywhere. Movies, TV shows, casual conversations, even well-meaning doctors reinforce this narrative.

Second, it might be emotionally easier. If cancer is just bad genetic luck, there’s no pressure to change anything. No need to rethink what’s on our plate or examine our stress levels. It’s “just the genes,” and that’s that.

Third, our medical system profits from this belief. There’s not a lot of money in telling people to eat more plants, reduce plastic exposure, or get better sleep. But there’s a massive industry built around genetic testing, chemo protocols, and high-tech interventions. The system isn’t incentivized to share the truth about prevention—it’s incentivized to treat disease after it happens.

But believing cancer is mostly inherited isn’t just outdated—it’s dangerous. Because it convinces people to give up before they’ve even started. It also convinces people to leave their health up to forces outside their control. Conventionally trained doctors know how to poison, cut, and radiate cancer cells, but they’re not much help in making your healthy cells inhospitable to becoming cancer cells in the future or creating an environment inhospitable to cancer growth and/or recurrence. Creating this type of body terrain is largely up to the individual. We have more control than we’ve been conditioned to believe.

The Real Genetics Story

Now, don’t get us wrong. Genetics do play a role—just not the way most people think.

Many of us are genetically predisposed to struggle with things like:

- Processing toxins efficiently

- Methylating properly (a key detox process)

- Managing inflammation effectively

- Metabolizing certain nutrients

As terrain advocates, we actually test our clients for these genetic variations. But here’s the crucial difference: these aren’t cancer genes. They’re genes that affect how well your body handles the everyday assault of modern life.

If you’ve got a genetic variation that makes you less efficient at detoxing, that doesn’t mean you’re destined to get cancer. It means you need to be more careful about what you expose yourself to. It means you might need extra support for your detox pathways. It’s information you can use, not a sentence you have to accept.

Our Story

Both of us have lived through cancer, and we didn’t just read the research—we lived it.

Marji was diagnosed in 2017. Instead of just following the conventional roadmap, she made radical shifts in how she ate, moved, thought, and lived. She improved her metabolism both during and after treatment. Today she’s doing great—not just surviving, but thriving.

Chris was diagnosed in 2016 with inoperable pancreatic cancer and started to get his affairs in order. But instead of accepting that prognosis, he took a different direction—one that focused on deep lifestyle transformation and terrain optimization. Nearly a decade later, he’s not just surviving—he’s teaching others how to do the same.

We’re not saying family history means nothing. It might make you more susceptible—but it doesn’t mean you’re destined to get cancer. It means you’ve got a heads-up. And that heads-up can be your wake-up call.

The Power Is in Your Hands

Though it’s been known for nearly two decades, the outdated belief persists. Here’s what we want you to understand: your daily choices matter more than you’ve been told.

**What you eat** affects inflammation, blood sugar, and cellular health.

**How you move** influences circulation, lymphatic flow, and stress hormones.

**How you sleep** impacts immune function and cellular repair.

**How you manage stress** affects cortisol levels and inflammatory markers.

**What you’re exposed to** influences your toxic load and cellular damage.

Cancer doesn’t have to be a waiting game or a genetic sentence. You have more power than you think. And every step you take toward optimizing your terrain—your body’s internal environment—is a step toward healing, resilience, and a future you can help shape.

The belief that cancer is mostly inherited isn’t just wrong—it’s holding you back from the very actions that could save your life.

It’s time to change that narrative.

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About the Authors

Marji Keith is a health coach and metabolic terrain advocate with a deep commitment to helping people heal from chronic illness by restoring balance across all aspects of life. After navigating her own cancer diagnosis, Marji turned her personal transformation into a mission: empowering others to take charge of their health with compassion, wisdom, and evidence-based tools.

Chris Joseph is also a cancer thriver, author of Life is a Ride, and a certified Terrain Advocate and Radical Remission Coach. Diagnosed with stage 3 inoperable pancreatic cancer in 2016, he defied the odds using lifestyle, metabolic, and integrative approaches. Today, Chris shares what he’s learned to help others reclaim their health, question conventional dogma, and chart their own healing journeys with humility and grit.

Together, Marji and Chris co-lead workshops, write essays, and coach individuals seeking a more empowering path to health. Learn more at www.terrainnavigators.com (http://www.terrainnavigators.com/).