By Dr. Emily Stern, a Gastroenterologist at MNGI Digestive Health
If you are turning 45, there is an important health milestone you should not overlook: it is time to begin screening for colon cancer.
Colorectal cancer screening is one of the most powerful preventive tools we have in medicine. It not only detects cancer early, when treatment is most effective, but can also prevent cancer from developing in the first place.
A Changing Trend: Colon Cancer Is Affecting Younger Adults
For many years, colon cancer was considered a disease that primarily affected older adults. Unfortunately, that is no longer true.
In the United States, colorectal cancer is now the leading cause of cancer-related death in adults younger than 50 when men and women are combined.[1] In the early 1990s, it ranked fifth. While deaths from most other major cancers in younger adults have declined over the past three decades, colorectal cancer deaths have continued to rise.[1]
More than 150,000 new cases of colorectal cancer are diagnosed each year in the United States, including nearly 20,000 cases in individuals under age 50.[2] Since approximately 2005, mortality from colorectal cancer has increased by about 1% per year in younger adults, while it has declined by 2–3% annually in older adults who undergo regular screening.[2] This contrast highlights a critical point: screening works.
Even more concerning, approximately three out of four adults under age 50 who are diagnosed with colorectal cancer already have advanced disease at the time of diagnosis.[1] Colon cancer often develops silently, without symptoms in its early stages. By the time warning signs such as rectal bleeding, abdominal pain, or unexplained weight loss appear, the disease may be more difficult to treat.
Why the Screening Age Was Lowered to 45
In response to these trends, the U.S. Preventive Services Task Force lowered the recommended starting age for colorectal cancer screening from 50 to 45 in 2021.[3] The American Cancer Society had previously updated its recommendation in 2018, and other major professional societies supported the change.[3][4]
This decision was based on substantial evidence. Research demonstrated that 45-year-olds today have roughly the same risk of colorectal cancer as 50-year-olds did in 1992, when screening at age 50 was first recommended.[5] In addition, studies show that adults aged 45–49 have similar rates of advanced precancerous polyps and early-stage cancers as individuals in their 50s. [5]
Lowering the screening age allows us to intervene earlier, when prevention and cure are most achievable.
How Screening Saves Lives
Colorectal cancer screening protects you in two important ways:
First, it detects cancer early, when treatment is more effective, and survival rates are significantly higher.
Second, and perhaps more importantly, screening can prevent cancer by identifying and removing precancerous polyps. Most colorectal cancers begin as polyps that grow slowly over time. Removing these polyps interrupts the progression of cancer.
The impact is substantial. Research shows that undergoing colonoscopy screening reduces the risk of dying from colorectal cancer by approximately 50%.[6] The landmark National Polyp Study demonstrated that removing polyps during colonoscopy reduced colorectal cancer deaths by 53% over 20 years.[7]
This is why colorectal cancer is considered one of the most preventable cancers, if screening is performed on time.
Why Colonoscopy Is Considered the Gold Standard
Several screening options are available, including stool-based tests and imaging studies. However, colonoscopy remains the most comprehensive screening method for many patients.[7]
Here is why:
- High accuracy: Colonoscopy detects 89–95% of advanced precancerous polyps, compared with 23% for fecal immunochemical testing (FIT) and 43% for stool DNA testing.[8][9]
- Immediate treatment: If a polyp is found during a colonoscopy, it can typically be removed during the same procedure.[4][8]
- Cancer prevention: Removing polyps prevents cancer from developing.[6][7][8]
- Long interval between tests: If results are normal, colonoscopy is generally repeated once every 10 years, the longest screening interval available.[8]
Stool-based tests may be appropriate for some patients, but abnormal results require a follow-up colonoscopy.[5] The most important step is choosing a screening strategy and completing it.
Who Should Begin Screening at 45?
The recommendation to begin screening at age 45 applies to adults at average risk.[3][4]
You are considered high risk if you have:
- A personal history of colorectal cancer or advanced polyps
- Inflammatory bowel disease
- A first-degree relative (parent, sibling, or child) diagnosed with colorectal cancer or advanced polyps.
If you have a first-degree relative with colorectal cancer or advanced polyps, screening should begin at age 40 or 10 years before the age at which your relative was diagnosed, whichever comes first.[4]
Certain inherited genetic conditions require even earlier and more frequent screening. If you are unsure about your personal risk, this is an important discussion to have with your physician.
The Screening Gap
Despite updated national guidelines, screening rates among adults aged 45–49 remain low. Only about 20% are currently up to date with recommended screening.[2]
Many people feel healthy and assume they are not at risk. Others feel anxious about the preparation or the procedure itself. However, colorectal cancer often develops without early warning signs. Waiting for symptoms can mean waiting until the disease is more advanced.[1]
Take Action
If you are 45 or older and have not yet been screened, I strongly encourage you to speak with your doctor.
Colorectal cancer screening is not simply a recommendation — it is an evidence-based intervention that saves lives. Mortality continues to rise in younger adults who are not being screened, while it declines in older adults who are.[1][2]
Screening may feel inconvenient, but it offers long-term protection and peace of mind. Early detection improves outcomes.
When it comes to colon cancer, starting at 45 can truly make a difference.
Disclaimer: This blog post is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
References:
- Siegel RL, Wagle NS, Jemal A. Leading cancer deaths in people younger than 50 years. JAMA. 2026;:2844189. doi:10.1001/jama.2025.25467.
- Giaquinto A, Kratzer T, Minihan A, et al. Colorectal Cancer Facts & Figures. American Cancer Society; 2025.
- Alteri R, Baptiste D, Butler Bell E, et al. Cancer Prevention and Early Detection Facts & Figures. American Cancer Society; 2025.
- Issaka RB, Chan AT, Gupta S. AGA clinical practice update on risk stratification for colorectal cancer screening and post-polypectomy surveillance: Expert review. Gastroenterology. 2023;165(5):1280-1291. doi:10.1053/j.gastro.2023.06.033.
- Patel SG, May FP, Anderson JC, et al. Updates on age to start and stop colorectal cancer screening: Recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol. 2022;117(1):57-69. doi:10.14309/ajg.0000000000001548.
- Bretthauer M, Løberg M, Wieszczy P, et al. Effect of colonoscopy screening on risks of colorectal cancer and related death. N Engl J Med. 2022;387(17):1547-1556. doi:10.1056/NEJMoa2208375.
- Zauber AG, Winawer SJ, O’Brien MJ, et al. Colonoscopic polypectomy and long-term prevention of colorectal cancer deaths. N Engl J Med. 2012;366(8):687-696. doi:10.1056/NEJMoa1100370.
- National Comprehensive Cancer Network. Colorectal Cancer Screening. Updated June 24, 2025.
- Imperiale TF, Porter K, Zella J, et al. Next-generation multitarget stool DNA test for colorectal cancer screening. N Engl J Med. 2024;390(11):984-993. doi:10.1056/NEJMoa2310336.
