Colon Cancer in Young Adults: Every Source Behind Our Video

What the video covers

1. Why are so many young people getting colon cancer?
2. What colorectal cancer is, and why catching it early matters
3. Why it hits men harder than women
4. Whether your birth year puts you at more risk
5. How modern food and lifestyle play a part
6. How to tell whether you are actually at risk
7. The warning signs most people miss
8. How to stop it before it starts

The short version

• One in five people diagnosed with colorectal cancer in the United States is now under 55, and rates keep falling in older adults while rising in younger ones.

  Source: American Cancer Society

• Your birth year matters. People born around 1990 face roughly double the colon-cancer risk, and about four times the rectal-cancer risk, of people born around 1950 at the same age.

  Source: Siegel et al., Journal of the National Cancer Institute

• Diets heavy in ultra-processed food are linked to the growths that precede early-onset colorectal cancer — one of the clearest signals researchers have found so far.

  Source: Mass General Brigham and Harvard researchers

• Young patients are the ones most often told it is nothing. Surveyed patients reported months of symptoms and several doctors before anyone looked properly.

  Source: Colorectal Cancer Alliance, Never Too Young survey (PDF)

Sources, in the order the video uses them

Each line says what the source is behind. Everything below is public — no paywalled claims, nothing quoted second-hand.

1. American Cancer Society Colorectal Cancer Drops in Older Adults and Rises in Younger Ones The split the video opens with: falling rates in older adults, rising rates under 55, and colorectal cancer's place among the leading causes of cancer death in young adults.
2. American Cancer Society Cancer Facts & Figures 2026 The year's estimates for new cases, deaths and lifetime risk that the introduction quotes.
3. Journal of the National Cancer Institute Siegel et al. — Colorectal Cancer Incidence Patterns in the United States, 1974–2013 (2017) The birth-cohort finding at the centre of the video: risk tracks the decade you were born in, not just your age today.
4. Bailey et al., JAMA Surgery Increasing Disparities in Age-Related Incidence of Colon and Rectal Cancer in the United States, 1975–2010 The projection for adults in their twenties and early thirties through 2030, and where those numbers come from.
5. Mass General Brigham Ultra-processed foods and the precursors of early-onset colorectal cancer The diet evidence in the "why is this happening" chapter, from the Harvard and Mass General Brigham study.
6. Colorectal Cancer Alliance ACS releases colorectal cancer estimates for 2024 Context for the risk chapter: how the annual estimates are read, and how the picture has shifted for people under 50.
7. Colorectal Cancer Alliance Never Too Young — 2020 survey report (PDF) What young patients actually experienced before diagnosis: repeated visits, misattributed symptoms and long delays.

Background we read while making it

These did not supply a specific number in the video, but they shaped how we explained things — and they are the best places to start if you want to read further.

1. Yale Medicine Colorectal Cancer: What Millennials and Gen Zers Need to Know A plain-language explainer on symptoms, screening age and what to ask a doctor.
2. MD Anderson Cancer Center Why are young adults getting colorectal cancer? An oncologist's view of the same trend, including family history and when screening should start early.
3. Mass General Brigham Colorectal Cancer Is Rising in Young Adults A clinician-written overview of the leading explanations and how strong the evidence for each one is.
4. Australian Journal of General Practice The alarming rise of early-onset colorectal cancer (2025) A recent review written for GPs — useful for how primary care is being told to handle young patients with symptoms.
5. PubMed Central Colorectal cancer in younger adults A review of what is known about tumour biology and outcomes in younger patients.
6. PubMed Central Young-onset colorectal cancer: A review The wider research picture, including the risk factors that keep coming up across studies.
7. Cancer Research Institute Why colorectal cancer is skyrocketing in young adults Background on the lifestyle factors under investigation, and what researchers still cannot explain.
8. GW Cancer Center Colorectal Cancer Is Rising in Younger Adults. Here's What You Need to Know — and Do. Practical guidance on screening conversations, which informed the last chapter of the video.

Clips used in the video

• CBS News — What's fueling the rise of colon cancer in young people?
• PBS NewsHour — What to know about the rise in colon cancer cases among young adults
• ABC7 News Bay Area — Colon cancer rising among young adults 20–49 years old: Here are their stories
• Inside Edition — Why Is Colon Cancer Becoming More Common in Young Adults?
• ABC News In-depth — Researchers puzzled by increasing number of young people getting bowel cancer
• Dr. Paulien Moyaert — How the Digestive System Works | 3D Animation
• Parkway Cancer Centre — 5 Stages of Colorectal Cancer Explained