How Cancer Develops
The basics most patients never learn. Not to scare you — to help you understand what you're actually fighting.
The Problem
When you're diagnosed, you're handed a treatment plan. Surgery dates, chemo schedules, radiation maps. What you're not handed is an explanation of how you got here — or why your body failed to stop it earlier.
This isn't an oversight. The system is built to treat, not to teach. Oncologists have 15 minutes per appointment and a protocol to follow. There's no billing code for "explain the biology."
But understanding how cancer develops isn't academic. It changes how you think about recovery, recurrence, and what you can actually control. Most patients fight blind. You don't have to.
How It Actually Works
Cancer isn't a thing that invades your body. It's your own cells breaking the rules.
Every day, your body produces billions of new cells. Most copy themselves perfectly. Some don't. Mutations happen constantly — from radiation, chemicals, random errors, or just bad luck. A healthy body catches these mistakes and kills the defective cells before they cause problems. That's the job of your immune system.
Cancer happens when that system fails. A mutated cell survives, divides, and keeps dividing. It learns to hide from immune surveillance, hijack blood supply, and spread.
The three-stage model:
1. Initiation
A cell's DNA is damaged. This can come from:
- Oxidative stress (free radicals from metabolism, pollution, inflammation)
- Chemical exposure (carcinogens in food, water, air, products)
- Radiation (UV, medical imaging, environmental)
- Viral infection (HPV, Hepatitis B/C, EBV)
- Random replication errors
One mutation usually isn't enough. Cancer typically requires multiple mutations in the same cell line — a process that can take years or decades.
2. Promotion
The damaged cell begins to proliferate. This stage is driven by:
- Chronic inflammation (keeps cells dividing, increases mutation opportunities)
- Hormonal imbalances (some cancers are hormone-sensitive)
- Immune suppression (surveillance system isn't catching the problem)
- Continued exposure to whatever caused the initial damage
This is often the longest stage. The tumor is growing but not yet detectable. This is also the stage where lifestyle and environment matter most.
3. Progression
The tumor becomes invasive. It develops its own blood supply (angiogenesis), breaks through tissue boundaries, and eventually metastasizes — spreading to other organs.
By the time most cancers are diagnosed, they've been developing for years. The 1-centimeter tumor that shows up on a scan contains about a billion cells. It didn't appear overnight.
Diagram: Three Stages of Cancer Development
Initiation → Promotion → Progression
The inflammation connection:
Chronic inflammation is the through-line. It shows up at every stage:
- Creates oxidative stress that damages DNA
- Signals cells to divide (more chances for errors)
- Suppresses immune function
- Promotes angiogenesis
- Enables metastasis
Researchers now believe chronic inflammation is involved in 15-25% of all cancers. Some estimates go higher. The sources of that inflammation — infections, obesity, environmental toxins, chronic stress, poor diet — are often modifiable.
What To Do
You can't undo what's already happened. But you can change the environment your body operates in going forward.
1. Reduce chronic inflammation
This is the highest-leverage intervention. Inflammation markers like CRP, IL-6, and TNF-alpha can be measured and tracked. Interventions that lower inflammation:
- Anti-inflammatory diet (Mediterranean, low processed food)
- Regular moderate exercise
- Adequate sleep (7-9 hours)
- Stress management
- Omega-3 fatty acids
- Reducing visceral fat
2. Minimize ongoing exposures
You can't eliminate all carcinogens, but you can reduce the big ones:
- Filter your water (PFAS, chlorine byproducts)
- Choose organic for high-pesticide foods (the "Dirty Dozen")
- Avoid heating food in plastic
- Reduce processed meat consumption
- Limit alcohol
- Check your home for radon
3. Support immune surveillance
Your immune system is still your best defense against recurrence. See "Your Immune System" and "Recovery Protocols" for specifics. The short version:
- Sleep is non-negotiable
- Chronic stress suppresses NK cell function
- Certain supplements have evidence for immune support
- Fasting cycles may help regenerate immune cells
4. Get the right tests
Beyond standard tumor markers, consider:
- CRP (C-reactive protein) — inflammation marker
- Vitamin D levels — deficiency is common and linked to worse outcomes
- Fasting insulin — metabolic health indicator
- CBC with differential — immune cell counts
These give you data to work with, not just hope.
Sources
Next Up
Your Immune System
NK cells, T cells, and the surveillance system that's supposed to catch cancer before it spreads.