The 40% of Cancers You Can Prevent — and What Protocol Tests to Prove It

Approximately 40% of all cancers diagnosed in the United States are attributable to modifiable risk factors. Not genetics. Not bad luck. Factors you can measure, track, and change.

That number comes from population-level epidemiologic data, and it includes some of the most common cancers: breast, colorectal, endometrial, pancreatic, liver, kidney, and esophageal. The risk factors are not mysterious. They’re the same metabolic, inflammatory, and behavioral markers that Protocol already measures across its protocols — most people just don’t realize these biomarkers have a cancer prevention angle.

This post maps specific Protocol measurements to specific cancer risks. Not vague advice to “live healthier.” Specific biomarkers, specific cancers, specific targets.

Fasting Insulin: The Growth Signal You’re Probably Not Tracking

Measured in: Protocol 3 (Metabolic Health)

Insulin is an anabolic hormone. Its job is to drive growth — glucose into cells, amino acids into muscle, lipids into storage. In cancer biology, that growth signal becomes a problem.

Hyperinsulinemia — chronically elevated fasting insulin — promotes cancer through several mechanisms:

• Direct mitogenic signaling. Insulin and insulin-like growth factor 1 (IGF-1) activate the PI3K/Akt/mTOR pathway, which drives cell proliferation. This is one of the most studied signaling cascades in oncology.
• Increased bioavailable estrogen. Elevated insulin reduces sex hormone-binding globulin (SHBG), increasing free estrogen levels. Estrogen is a growth factor for hormone-receptor-positive breast cancer and endometrial cancer.
• Chronic inflammation. Insulin resistance drives systemic inflammation, creating a microenvironment that favors tumor initiation and progression.

The cancers most strongly associated with hyperinsulinemia: breast (particularly post-menopausal), colorectal, pancreatic, and endometrial. The data is [B]-level — large observational studies consistently show the association, though no RCT has tested whether lowering insulin directly reduces cancer incidence.

Protocol target: Fasting insulin below 10 uIU/mL, HOMA-IR below 2.5. If you’re above these thresholds, your Protocol 3 assessment will flag it and your care team will build a plan to bring it down through dietary changes, exercise prescription, and medication if indicated.

Most standard physicals don’t measure fasting insulin. They measure fasting glucose and HbA1c, which only become abnormal after insulin resistance has been present for years. By the time glucose is elevated, the horse has left the barn. Fasting insulin catches the problem upstream.

hsCRP: Chronic Inflammation and Cancer Risk

Measured in: Protocol 1 (Cardiovascular Risk)

High-sensitivity C-reactive protein (hsCRP) is a marker of systemic inflammation. Protocol measures it as part of cardiovascular risk assessment, but its relevance extends directly to cancer.

Chronic low-grade inflammation promotes cancer through:

• DNA damage. Reactive oxygen species generated during inflammatory responses cause mutations in tumor suppressor genes and oncogenes.
• Tumor microenvironment. Inflammatory cytokines (IL-6, TNF-alpha) create conditions that favor angiogenesis, the formation of new blood vessels that tumors need to grow.
• Immune evasion. Chronic inflammation paradoxically suppresses the adaptive immune response that would otherwise identify and destroy early cancer cells.

Elevated hsCRP (above 3.0 mg/L) is associated with increased risk of colorectal, lung, breast, and prostate cancer in observational studies. The CANTOS trial — originally designed to test whether reducing inflammation with canakinumab (an IL-1beta inhibitor) prevents heart attacks — found a secondary signal: a reduction in lung cancer incidence and mortality in the treatment group. That was [A]-level evidence that inflammation reduction can affect cancer outcomes, though canakinumab is not used for cancer prevention outside of trials.

Protocol target: hsCRP below 1.0 mg/L (optimal), below 3.0 mg/L (acceptable). Persistently elevated hsCRP triggers investigation of the source — visceral adiposity, poor sleep, undiagnosed infection, autoimmune disease, or dietary inflammation.

Body Composition: Visceral Fat and 13 Cancer Types

Measured in: Protocol 2 (DEXA body composition scan)

Obesity — specifically visceral adiposity — is associated with increased risk of at least 13 cancer types: esophageal adenocarcinoma, gastric cardia, colorectal, liver, gallbladder, pancreatic, breast (post-menopausal), endometrial, ovarian, kidney (renal cell), meningioma, thyroid, and multiple myeloma. This is [A]-level evidence from IARC (International Agency for Research on Cancer), based on extensive systematic review.

BMI captures some of this risk, but it’s a blunt instrument. A muscular person with a BMI of 28 and low visceral fat has a different cancer risk profile than a sedentary person with the same BMI and high visceral fat. DEXA scanning separates lean mass from fat mass and provides regional fat distribution data, including visceral adipose tissue (VAT) estimates.

The mechanism is multi-factorial. Adipose tissue is an endocrine organ — it produces estrogen via aromatase, elevates insulin, and alters adipokine signaling (increased leptin, decreased adiponectin). Visceral fat is metabolically active and generates chronic low-grade inflammation, the same IL-6 and TNF-alpha that promote cancer initiation. And for esophageal and gastric cancers, visceral obesity increases intra-abdominal pressure and gastroesophageal reflux, directly damaging esophageal tissue.

Protocol target: Visceral fat within age- and sex-appropriate reference ranges on DEXA. Tracked longitudinally to measure response to interventions.

Alcohol: The Group 1 Carcinogen in Your Glass

Assessed in: Protocol 9 (Cancer Prevention) intake

Alcohol is classified as a Group 1 carcinogen by the WHO’s International Agency for Research on Cancer (IARC). Group 1 is the highest certainty level — the same category as tobacco smoke, asbestos, and ionizing radiation. This classification is not controversial within the oncology research community, though it remains poorly communicated to the public.

The dose-response relationship is linear for several cancers, meaning there is no safe threshold below which risk disappears:

• Breast cancer: 7-10% increased risk per standard drink per day. A woman who drinks one glass of wine daily has a measurably higher breast cancer risk than a woman who doesn’t drink. At two drinks per day, the risk increase is 20% or more.
• Colorectal cancer: Risk increases above approximately 2 drinks per day, though some data suggests risk elevation begins at lower levels.
• Esophageal, liver, oral cavity, pharyngeal, laryngeal cancers: All have strong dose-response relationships with alcohol intake.

The mechanism involves acetaldehyde — alcohol’s first metabolite — which is itself a carcinogen that damages DNA directly. Alcohol also increases estrogen levels, impairs folate metabolism, and acts as a solvent that increases mucosal permeability to other carcinogens.

Protocol approach: Alcohol consumption is quantified during the Cancer Prevention protocol intake. Members receive their risk data in specific terms — not “drink less” but “your current consumption of X drinks per week is associated with a Y% increase in Z cancer risk.” The decision is the member’s. The data is Protocol’s job.

Physical Activity: 10-20% Risk Reduction Across 7+ Cancer Types

Assessed in: Protocol 4 (Physical Capacity)

Regular physical activity at the level of 150-300 minutes per week of moderate-intensity exercise reduces the risk of at least 7 cancer types by 10-20%. The evidence is [B]-level — large prospective cohort studies consistently demonstrate the association.

The cancers with the strongest evidence for activity-related risk reduction: breast, colorectal, endometrial, bladder, esophageal, kidney, and gastric. The mechanisms include:

• Insulin sensitization. Exercise directly reduces fasting insulin and improves insulin sensitivity, addressing the hyperinsulinemia pathway.
• Inflammation reduction. Regular moderate exercise reduces circulating inflammatory markers including hsCRP and IL-6.
• Immune function. Exercise enhances natural killer cell activity and improves immune surveillance of abnormal cells.
• Hormone regulation. Activity reduces circulating estrogen levels in post-menopausal women, partly by reducing adipose tissue.
• Improved gut motility. For colorectal cancer, exercise reduces colonic transit time, limiting contact between potential carcinogens and the intestinal lining.

Protocol target: 150-300 minutes per week of moderate-intensity activity, measured and tracked through Protocol 4. Strength training at least 2 sessions per week. Both aerobic and resistance exercise have independent associations with cancer risk reduction.

Vitamin D: The Observational Signal

Measured in: Protocol 6 (Nutrient Optimization)

The relationship between vitamin D and cancer risk is one of the most studied and most debated in cancer prevention. Observational data consistently associates higher serum 25-hydroxyvitamin D levels with lower colorectal cancer risk. The evidence for other cancer types (breast, prostate) is weaker and less consistent.

The VITAL trial (25,871 participants, 5+ years of follow-up) tested whether vitamin D supplementation (2,000 IU/day) reduced cancer incidence. The primary endpoint was negative — no overall reduction in cancer incidence. But secondary analyses showed a potential reduction in cancer mortality, particularly among those with lower baseline vitamin D levels.

Evidence grade: [B] for colorectal cancer risk reduction at levels of 40-60 ng/mL. [C] for other cancer types.

Protocol target: Serum 25-hydroxyvitamin D of 40-60 ng/mL, with supplementation titrated to achieve and maintain this range. This target is set based on the convergence of observational cancer data, bone health data, and immune function data — not on cancer risk alone.

Tobacco: The Highest-Yield Prevention Intervention

Assessed in: Protocol 9 (Cancer Prevention) intake

Tobacco use remains the single largest preventable cause of cancer death worldwide. Lung cancer alone kills more people than breast, prostate, and colorectal cancers combined, and approximately 80-85% of lung cancer cases are attributable to smoking.

Beyond lung cancer, tobacco increases risk for at least 15 other cancer types: bladder, cervical, colorectal, esophageal, kidney, laryngeal, liver, oral cavity, pancreatic, pharyngeal, stomach, and several others.

Protocol approach: Current tobacco use is assessed at intake. For current smokers, cessation support is the single highest-return intervention in the cancer prevention plan — higher than any screening test, supplement, or biomarker optimization. Eligible former smokers (20+ pack-year history, quit within 15 years) are enrolled in annual low-dose CT screening, which has [A]-level evidence for mortality reduction.

The Cross-Protocol Picture

What makes Protocol’s approach different from a standard cancer screening visit: the biomarkers you’re already tracking for cardiovascular health and metabolic optimization are also cancer prevention biomarkers. You don’t need separate tests. You need someone connecting the data.

Biomarker	Primary Protocol	Cancer Relevance
Fasting insulin / HOMA-IR	Protocol 3	Breast, colorectal, pancreatic, endometrial
hsCRP	Protocol 1	Colorectal, lung, breast
Visceral fat (DEXA)	Protocol 2	13+ cancer types
Vitamin D	Protocol 6	Colorectal (strongest), others
Physical activity	Protocol 4	7+ cancer types
Alcohol intake	Protocol 9	Breast, colorectal, liver, esophageal, oral
Tobacco use	Protocol 9	15+ cancer types

Each of these is measurable. Each has a target. Each is tracked over time. When you optimize your metabolic health, reduce inflammation, improve body composition, and address behavioral risk factors, you’re reducing cancer risk through the same mechanisms that reduce heart disease risk.

The 40% of preventable cancers are preventable because the risk factors are modifiable. But modifiable only matters if you measure them, set targets, and track progress. That’s what the protocols do.

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Want to see which of your biomarkers carry cancer prevention implications? Book a Discovery Call to learn how Protocol’s cross-protocol approach tracks the modifiable risk factors behind 40% of all cancer diagnoses.