Colorectal Cancer Can Run in Families. But Prevention Can Too.

March is Colorectal Cancer Awareness Month and if you have a family history of colorectal cancer, this is the month to stop putting off the conversation you've been meaning to have.

Not the conversation with your gastroenterologist. Not the one about scheduling a colonoscopy (though that matters too). The earlier one, the one about whether what runs in your family is hereditary, whether your relatives' diagnoses are a pattern rather than a coincidence, and whether you qualify for a level of monitoring that most people never know exists.

Most people who qualify for hereditary colorectal cancer evaluation have no idea they qualify. This post is for them.

1 in 279 people carry Lynch syndrome, the most common hereditary colorectal cancer syndrome. An estimated 95% don't know it.

What Makes Colorectal Cancer Hereditary?

Not every colorectal cancer that runs in a family is hereditary. But some patterns are impossible to ignore and a genetic counselor is trained to tell the difference.

Hereditary colorectal cancer syndromes are caused by pathogenic variants in specific genes passed down through families. The most common is Lynch syndrome, caused by variants in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2. Familial adenomatous polyposis (FAP), caused by variants in the APC gene, is less common but equally significant.

These aren't rare edge cases. Lynch syndrome alone affects approximately 1 in 279 people, making it more common than many conditions your doctor screens for routinely. The problem isn't the prevalence. It's the recognition.

Lynch syndrome affects 1 in 279 people making it more common than BRCA pathogenic variants. An estimated 95% of carriers have never been diagnosed.

Family History Red Flags: When a Pattern Becomes a Signal

You don't need a genetic test result to start asking the right questions. Your family history is already data and the following patterns warrant a conversation with a genetic counselor:

• Colorectal or endometrial cancer diagnosed before age 50 in a first- or second-degree relative

• Multiple relatives on the same side of the family diagnosed with colorectal, endometrial, ovarian, or gastric cancer

• The same cancer type appearing across two or more generations

• A single relative with multiple primary cancers, for example, both colorectal and endometrial cancer

• A known hereditary cancer syndrome anywhere in the family

These aren't arbitrary thresholds. They reflect the inheritance patterns of hereditary colorectal cancer syndromes and they're the same criteria genetic counselors use when conducting a formal family history assessment.

If any of the above describes your family, you may qualify for hereditary colorectal cancer genetic testing regardless of your own personal cancer history, and without a referral from another provider.

Lynch Syndrome: The Most Preventable Cancer Syndrome Most People Have Never Heard Of

Lynch syndrome deserves its own section because it is both remarkably common and remarkably preventable, yet most carriers are diagnosed only after their first cancer rather than before it.

Lynch syndrome increases lifetime risk for colorectal cancer significantly above population average, with risk varying by specific gene involved and sex. It also elevates risk for endometrial cancer (the most common Lynch-related cancer in women), ovarian cancer, gastric cancer, urinary tract cancer, and several others.

The reason Lynch syndrome is so preventable is straightforward: colonoscopy surveillance starting at age 20–25 dramatically reduces colorectal cancer incidence and mortality in Lynch carriers. The cancer doesn't have to happen. The precancerous polyps that precede it can be identified and removed before they progress, but only if colonoscopy is happening at the right interval, for the right reason, starting at the right age.

Standard population colonoscopy guidelines recommend starting at age 45. For a Lynch carrier, that recommendation should be age 20–25, with colonoscopy every 1–2 years. That gap, 20 years of missed surveillance, is where Lynch-related colorectal cancers develop in people who were never told they had Lynch in the first place.

Lynch-related colorectal cancer is largely preventable with the right surveillance protocol, but only if Lynch syndrome is identified first.

What Does a Hereditary Cancer Genetic Counseling Appointment Actually Involve?

One of the biggest barriers to hereditary cancer genetic counseling is simply not knowing what it is. It's not a blood draw. It's not a scary result delivered without context. And it's not only for people who are already sick.

A hereditary cancer genetic counseling appointment at Empower Genetics begins with a comprehensive family history review (typically three generations across both sides of your family) with cancer types, ages at diagnosis, and relevant ancestry noted. This family history assessment alone can identify patterns that warrant further evaluation, even before any testing is ordered.

From there, your genetic counselor will:

• Explain which hereditary syndromes are consistent with your family history pattern

• Discuss whether genetic testing is recommended, and if so, which panel is most appropriate

• Walk you through what a positive result would mean and what a negative result would and would not rule out

• Help you think through how to share relevant information with other family members who may also be at risk

• Coordinate with your other providers so that any recommendations integrate smoothly into your existing care

The appointment is a conversation, not a procedure. Most patients describe it as the clearest, most organized health conversation they've ever had about their family history. The goal is not to generate anxiety. It's to replace the vague, unaddressed worry that family history concerns tend to produce with something concrete: a risk assessment, a plan, and a next step.

How to Start Building Your Family History Before Your Appointment

You don't need a complete family history to book a genetic counseling appointment and many patients come in with significant gaps, especially if family members are estranged, deceased, or reluctant to discuss health history. A genetic counselor is trained to work with incomplete information.

That said, the more information you can gather in advance, the richer your risk assessment will be. Here's a simple starting point:

Step 1: First-Degree Relatives

Parents, siblings, and children. For each person, note: any cancer diagnoses, the type of cancer, and the age at diagnosis. If someone has had multiple cancer diagnoses, list each one.

Step 2: Second-Degree Relatives

Grandparents, aunts, uncles, and half-siblings. Same information: cancer type and age at diagnosis. Note which side of the family each person is on (maternal vs. paternal, this distinction matters).

Step 3: Flag the Patterns

Before your appointment, look for the red flags listed earlier in this post: early-onset diagnoses, multiple cancers in one person, the same cancer type across generations. You don't need to interpret them, that's what your genetic counselor is for. You just need to bring them.

What Happens After a Hereditary Diagnosis: Surveillance Options

A hereditary colorectal cancer diagnosis, whether Lynch syndrome, FAP, or another syndrome, is not a prognosis. It's a roadmap. And the surveillance options available to people with known hereditary syndromes are significantly more proactive than standard population guidelines.

Depending on your specific syndrome and gene involved, a surveillance plan may include:

• Colonoscopy starting at age 20–25 (Lynch syndrome) or in early adolescence (FAP), repeated every 1–2 years

• Annual endometrial sampling and transvaginal ultrasound for Lynch carriers with a uterus, beginning at age 30–35

• Consideration of risk-reducing surgeries (colectomy, hysterectomy, salpingo-oophorectomy) depending on gene, risk level, and personal preferences

• Upper endoscopy for gastric cancer surveillance in Lynch carriers with specific gene variants or family history of gastric cancer

• Cascade testing for first-degree relatives so that siblings, parents, and children who may carry the same variant can be evaluated and enter surveillance themselves

None of these decisions are made for you. A genetic counselor presents options, explains the evidence behind each recommendation, and supports you in making decisions that align with your values, your circumstances, and your relationship with risk. The goal is always the same: more information, earlier. More options, before the window narrows.

 A hereditary colorectal cancer diagnosis is not a prognosis. It's a roadmap and the surveillance options it unlocks are what make early prevention possible.

This March: From Awareness to Action

Colorectal Cancer Awareness Month is good at creating awareness. What it doesn't always create is a clear next step for the person who reads a statistic, thinks of their father's diagnosis, and then closes the tab because they don't know what to do with that feeling.

Here's the next step: a hereditary cancer genetic counseling consultation. It starts with your family history. It doesn't require a referral. It doesn't require a diagnosis. And it can be done from anywhere via telehealth.

If colorectal cancer runs in your family, this month is the right time to find out whether what runs in your family is a pattern and whether that pattern is one a surveillance plan could interrupt.

Prevention is not reactive. It's a decision you make before there's something to react to.

Ready to understand your hereditary colorectal cancer risk?

Board-certified genetic counseling via telehealth· No referral required

→ Book a Consultation at empowergeneticshealth.com

About the Author

Jordan Rausch, MS, CGC is a board-certified genetic counselor and founder of Empower Genetics, a telehealth-based genetic counseling practice serving patients across Idaho. Empower Genetics offers hereditary cancer risk assessment, pharmacogenomics, preconception carrier screening, cardiovascular genetics, neurogenetics, and DTC results review. Learn more at empowergeneticshealth.com.