Colorectal Cancer Rising in Young Adults: Symptoms & Risks You Need to Know

Colorectal cancer is now the leading cause of cancer death for Americans under 50, a stark shift from previous decades, according to a recent analysis by the American Cancer Society. The finding underscores a worrying trend and is prompting calls for increased awareness of symptoms, earlier screening, and a re-evaluation of how doctors approach the disease in younger patients.

The experience of Becca Lynch, a 29-year-ancient cybersecurity professional from Denver, Colorado, illustrates the challenges. Initially dismissing her symptoms – “pencil thin” bowel movements and frequent trips to the bathroom, eventually accompanied by dark blood – as stress, Lynch only sought medical attention after seeing a similar story shared on Instagram by Cass Costley. Even then, she delayed a colonoscopy for several months. When she finally underwent the procedure, she received a diagnosis of stage 3B colon cancer.

A Common Story, A Delayed Diagnosis

Lynch’s story, according to Rebecca Siegel, an epidemiologist and senior director of cancer surveillance research at the American Cancer Society and lead author of the analysis, is far from unique. Approximately three-quarters of individuals under 50 receive an advanced colorectal cancer diagnosis, often because they haven’t been screened through regular colonoscopies and tend to downplay their symptoms, assuming they are too young to be at risk. This delay in diagnosis allows the cancer to progress, making treatment more difficult.

Many individuals initially attribute rectal bleeding to less serious conditions like hemorrhoids, a common misconception reinforced by online search results. Costley, who tragically passed away from the disease, also initially believed her symptoms were due to hemorrhoids and delayed seeking medical attention, as she shared in an interview with Today.

Understanding Lynch Syndrome and Hereditary Risk

While the reasons for this increase in colorectal cancer among younger adults are still being investigated, genetic factors play a significant role in some cases. Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common inherited cancer syndrome that increases a person’s risk for colon cancer. According to the American Cancer Society, individuals with Lynch syndrome are at higher risk of developing colorectal cancer at younger ages, often before 50. They also face an increased risk of other cancers, including endometrial, ovarian, stomach, and others. Lynch syndrome is caused by inherited mutations in genes responsible for DNA repair, such as MLH1, MSH2, MSH6, and PMS2.

Similarly, the CDC confirms that Lynch syndrome is the most common cause of hereditary colorectal cancer, highlighting the importance of genetic counseling and testing for individuals with a family history of the disease.

Screening and Early Detection

Siegel emphasizes the importance of prompt medical attention for anyone experiencing rectal bleeding for more than a couple of weeks. She recommends stool tests like Cologuard and the FIT test as initial screening options for those hesitant about a colonoscopy. These tests can help rule out potential cancer and guide further investigation.

However, it’s key to note that screening guidelines traditionally focused on individuals over 50. The rising incidence in younger adults is prompting discussions about lowering the recommended age for routine screening, though a consensus has not yet been reached. The American Cancer Society currently recommends that individuals at average risk start regular screening at age 45.

Shifting Treatment Paradigms

The increase in colorectal cancer diagnoses among younger individuals also necessitates a shift in treatment approaches. Doctors are accustomed to treating patients in their 70s with different priorities than those in their 30s and 40s. Siegel points out that younger patients may be more concerned about preserving fertility and sexual function, factors that require careful consideration during treatment planning. Open discussions about these potential side effects and available options for preservation are crucial.

The “Birth Cohort Effect” and Potential Environmental Factors

Experts are still working to understand the underlying causes of this trend. Siegel suggests a “birth cohort effect,” meaning that individuals born after the 1950s may be facing heightened risk due to exposures or risk factors introduced mid-20th century. This suggests a common environmental or lifestyle factor impacting successive generations.

Changes in the food supply are being investigated as potential contributors. Increased consumption of processed foods, processed meats, and foods packaged in plastic are all being considered, although definitive proof remains elusive. The potential role of microplastics, which can cross the blood-brain barrier, is also under scrutiny, as Siegel notes.

Disparities in Risk and the Need for Further Research

Certain populations face a disproportionately higher risk. Alaska Natives, for example, have the highest documented colorectal cancer mortality rates globally. However, limited funding hinders research into the specific factors driving this disparity. Understanding the reasons behind this elevated risk could provide valuable insights into the broader increase in colorectal cancer among younger adults.

Beyond the Numbers: Raising Awareness and Reducing Stigma

Prosanta Chakrabarty, a 47-year-old evolutionary biologist from Louisiana, exemplifies the challenges faced by even those proactively seeking preventative care. Despite maintaining a healthy lifestyle and undergoing annual colonoscopies, he was diagnosed with advanced colon cancer in 2024. His ongoing battle, including 24 rounds of chemotherapy, highlights the aggressive nature of the disease and the need for continued research.

Both Chakrabarty and Lynch are actively sharing their stories to combat the embarrassment and stigma surrounding bowel health, encouraging others to seek medical attention promptly. Lynch’s Reddit AMA and Chakrabarty’s viral video of himself walking through an inflatable colon are examples of their efforts to raise awareness and break down barriers to diagnosis.

What’s Next: Ongoing Surveillance and Guidance Updates

The American Cancer Society and other public health organizations are continuously monitoring colorectal cancer trends and updating screening guidelines as new evidence emerges. Further research is needed to identify the specific risk factors driving the increase in diagnoses among younger adults and to develop more effective prevention and treatment strategies. Ongoing surveillance will be critical to tracking the impact of these efforts and ensuring that individuals receive timely and appropriate care.