Colorectal Cancer: Rising Cases in Young Adults Drive Focus on Screening and New Treatments

Colorectal cancer has become the leading cause of cancer death among people under 50, despite overall cancer deaths continuing to decline. According to the World Health Organization, colorectal cancer is the third most common cancer and the second leading cause of cancer-related deaths worldwide. For individuals under 50, rates of colorectal cancer have increased by about 3% annually since 2010, and death rates have also increased by 1% annually in people younger than 50 since 2005.

"Colorectal cancer is one of the most preventable cancers," said an associate professor of medicine. "Through screening, we can identify and remove precancerous polyps before they even become cancer, which makes expanding access to screening one of our most powerful tools."

Since the recommended screening age was lowered from 50 to 45 in 2021, fewer than 1 in 4 adults in this age group have completed screening, according to a study analyzing data from more than 13,000 respondents. The study found that about 22.5% were screened, most commonly through colonoscopy (61%) or stool-based tests (32%). While unmet social needs such as housing, transportation, or food insecurity were linked to lower screening in unadjusted analyses, the differences disappeared after adjusting for income, insurance, education and location. Transportation insecurity was associated with higher use of stool-based tests, but other social barriers were not significant.

For colon cancer, surgery is typically the first and main step when the disease hasn't spread to distant organs. The goal is to remove the cancerous part of the colon along with nearby lymph nodes, which are the first places cancer spreads. After surgery, the removed tissue is examined under a microscope to confirm the stage of the disease and decide whether additional treatment, such as chemotherapy, is needed. In early-stage colon cancer (stages 1 and 2), surgery alone may be curative. Many patients won't need further treatment beyond regular follow-ups. In stage 3 disease, chemotherapy after surgery is usually recommended to help reduce the risk of the cancer returning.

Rectal cancer, found in the last several inches of the large intestine, is often treated differently from colon cancer. Because the rectum is deep in the pelvis next to other organs and structures, such as nerves that control bowel and bladder function, doctors often use a multidisciplinary approach. For many rectal cancers, especially those that are locally advanced or close to critical structures, treatment typically begins with chemotherapy and radiation before surgery. The aim is to shrink the tumor so it can be removed more completely and safely and reduce the risk that it will come back. This sequence, called neoadjuvant therapy, is less common in colon cancer but standard in many cases of rectal cancer, which have a higher risk of local recurrence.

Many colorectal operations are performed using minimally invasive techniques such as laparoscopy or robotic-assisted surgery. These methods use small incisions and advanced instruments that allow surgeons to work precisely, leading to fewer complications, less pain and a faster recovery than with traditional open surgery. For rectal cancer, minimally invasive techniques also are used, but the surgery can be more complex because of the tighter space in the pelvis and the need to preserve nerves. Robotic surgery in particular offers 3D visualization and refined control that can be especially helpful.

A team found that combining zanzalintinib, a multi-targeted therapy, with atezolizumab, an immune checkpoint inhibitor, significantly improves survival in patients with previously treated metastatic colorectal cancer. In the trial, patients receiving the combination lived longer and experienced delayed disease progression compared with those treated with the standard therapy, regorafenib. The combination reduced the risk of death by about 20% and doubled the percentage of patients alive at two years. Researchers believe zanzalintinib helps overcome the tumor's immunosuppressive environment, making it more responsive to immunotherapy — even in patients whose cancers are microsatellite stable, a group that historically has not benefited from immune checkpoint inhibitors.

In a study evaluating a novel immune-based strategy to prevent cancer recurrence, researchers found that the investigational vaccine ELI-002 2P generated powerful and lasting immune responses in patients with KRAS-driven pancreatic and colorectal cancers. Final results from the phase 1 trial showed that 84% of patients developed KRAS-specific T cells, including both helper and killer T cells, with many responses sustained over time. Patients who mounted the strongest immune responses experienced markedly longer relapse-free and overall survival, with median survival not reached in the high-response group compared with significantly shorter survival among those with weaker responses. The off-the-shelf vaccine, designed to target common KRAS mutations without requiring a personalized manufacturing process, also cleared tumor biomarkers in a subset of patients and stimulated broader immune activity against additional cancer-associated mutations.

There's no way to guarantee the prevention of colorectal cancer, and it can be a random event. But avoiding smoking and heavy alcohol use can reduce risk. A healthy diet that includes plenty of fruits and vegetables, and avoiding processed meats like hot dogs and bacon is also important. According to the American Cancer Society, high consumption of red meat is also linked to a higher risk of colorectal cancer. A 2024 study published in the journal Cancer Epidemiology, Biomarkers & Prevention found that people with the highest level of red meat intake had a 30% increased risk for colorectal cancer. In the same study, individuals with the highest level of processed meat intake had a 40% increased risk.

Exercise is another critical factor in risk reduction. It may also lower the risk of recurrence. A 2025 study published in the New England Journal of Medicine found that a three-year structured exercise program resulted in "significantly longer disease-free survival" and longer overall survival.

Colorectal cancer can be hereditary, and some genetic syndromes, like Lynch syndrome, are linked to it. If anyone has a first-degree relative, or a strong family history, they should see a genetic counselor for genetic testing and be considered for a colonoscopy at an earlier age.

Chronic inflammation is a risk factor for various cancers, including colorectal cancer. Inflammatory bowel disease and Crohn's disease are both risk factors for the development of cancer due to the long-term inflammation of the colon. Chronic inflammation related to alcohol use and ultra-processed foods can lead to an increased risk as well. It's possible that inflammation generates free radicals, which are unstable molecules that cause DNA damage.

It's unclear why the rise in colorectal cancer among younger adults is occurring, and potential drivers – like ultra-processed foods, sugary beverages and processed meats – are under investigation. Higher antibiotic prescribing in childhood is linked to a higher risk of colorectal cancer in some studies; other research has found no evidence that antibiotic use in adulthood increases risk.

Colorectal cancer can be asymptomatic, so screening is important. Symptoms can include blood in your stool or a change in stool pattern, such as frequent or months-long constipation or diarrhea. Sudden weight loss or abdominal pain can also indicate that you should speak with your care provider. The cure rate for stage 4 is closer to 15%. Treatments can include surgery, radiotherapy, chemotherapy, targeted therapy and immunotherapy, depending on the stage and characteristics of the cancer.