Colon cancer: this is the most common tumor warning sign in Spain |Watch outPlus

Colorectal cancer is the most common cancer in our country.It is estimated that more than 40,000 new cases will be diagnosed by 2026.We spoke to a cancer expert to explain how we can detect cancer in time and what signs let us suspect something is wrong.

Colon cancer: these are the warning symptoms of the most common tumor in Spain

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Colon cancer is the most common tumor in our country.According to estimates, more than 40,000 new cases will be diagnosed in 2026. We spoke with an oncologist to explain how we can detect it early, the signs that should make us suspect that something is wrong.

Updated: Tuesday, March 31, 2026 12:28:04 CEST Colon cancer is currently the most diagnosed tumor in our country.According to the Cancer Statistics in Spain 2026 report prepared by the Spanish Society of Medical Oncology (SEOM) and the Spanish Network of Cancer Registries (REDECAN), colon and rectal are the most commonly diagnosed cancers in Spain in 2026.(44,132 new cases), breast (38,318), lung (34,908), prostate (34,833) and bladder (23,929).According to SEOM, colon cancer is the second deadliest in our country after lung cancer.The good news is that the death toll is down.Anderson Cancer Center Madrid - Hospitén "Multidisciplinary approaches, personalized treatment and early diagnosis have increased patient recovery rates and reduced deaths due to colorectal cancer in recent years," says Martin Valades.

Marta Orozco of the Medical Oncology Department of the Gastrointestinal Oncology Department of the same center explains: "Early detection is one of the cornerstones of colon cancer. It allows the disease to be detected at an early stage and early lesions to be detected and treated before they develop into cancer."

This "represents a significant reduction in mortality and a greater chance of cure."

And how can we detect it in time?One of the keys is in screening programs.Here, he reports, "the primary tool is the fecal occult blood test, a simple and noninvasive test that can detect the presence of bleeding under a microscope."

We should not forget that "the effectiveness of this program is widely proven", but "their influence depends to a large extent on the participation of the population and the correct continuity of the diagnostic process after positive results."Therefore, it is important to "encourage adherence to screening in people for whom it is indicated"

But screening not only helps identify potential injuries, but you also need to know and pay attention to the warning symptoms and, she reports, ask people early when they show up."The combination of prevention, screening and early diagnosis allows the disease to be detected at an early stage, where cure rates are higher," he said.

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That said, what are the signs that make you suspect something is wrong?Orozco points out:

Presence of blood in the stool (rectal bleeding)

Persistent changes in bowel habits, such as diarrhea or constipation, which are not normal

Stools that are narrow or look different than usual

Abdominal pain

The appearance of iron deficiency anemia for no apparent reason

More common signs may also appear, such as:

Unexplained weight loss.

"When these symptoms persist over time or have no apparent cause, attention should be paid," the expert believes.However, it should also be noted that "in many cases they are due to benign disease."

Another thing to take into account is the age of the patients.This is because, as he identified, "in recent years we have seen an increase in cases in younger patients, who often have a low perception of risk. This can lead to a delay in diagnosis, minimizing symptoms or attributing them to trivial causes".For this reason, the exhibitor believes "it is fundamental to emphasize that age should not be a reason to ignore warning signs."

Remember this: "In the case of any continuous change in bowel habits, bleeding or unknown symptoms, it is good to consult without delay since early detection remains one of the most decisive factors to improve the prognosis of this disease."

How to prevent colon cancer

The good news about colon cancer is that, like other types of cancer, it is largely preventable because "most risk is related to modifiable factors."

Therefore, according to the expert, "we know that some habits, such as a sedentary lifestyle, obesity, smoking, alcohol consumption and an unhealthy diet, especially rich in highly processed foods and poor in fibre, fruit and vegetables, increase the risk of developing this disease".On the contrary, "following a healthy lifestyle can significantly reduce this risk."

The main preventive measures include:

Maintain regular physical activity

Control body weight

Avoid tobacco

Avoid alcohol

Follow a balanced diet.Especially according to the Mediterranean style.Rich in fiber, fruits, vegetables and fresh foods.

Therefore, the expert concluded, "combining good habits and participating in screening programs is the most effective strategy to reduce the impact of colon cancer on the population."