He Wrote the Perfect Crimes. His Body Had Been Plotting for a Decade.

On July 23, 2026, Japanese author Keigo Higashino passed away from colorectal cancer. He was 68.

The news came from his publisher, Kodansha. For countless readers, scrolling through their phone feeds, the first reaction was probably three words: It can’t be. A man who had spent decades writing about killers. How could he have missed the quietest killer inside his own body?

The question has an answer. It’s just not a pleasant one.

Why does a tumor grow for over a decade without being noticed?

Colorectal cancer develops at an extremely slow pace. From a tiny polyp on the intestinal wall to a malignant tumor that penetrates the muscle layer takes, on average, 10 to 15 years.

Slowness, in itself, is good news. It means there’s plenty of time to catch it. But slowness has a cost: the body sends its signals far too late.

The nerves in the human intestine are mainly distributed in the outer layer of the intestinal wall, responsible for sensing large physical changes like stretching and ischemia. Early-stage tumors, however, grow only in the innermost mucosal layer—they don’t touch nerves, they don’t compress the intestinal wall. They can grow quietly inside you for years without you ever knowing.

This isn’t a metaphor; it’s anatomical fact. Two layers of tissue separate the nerves from the tumor. The tumor must first penetrate the submucosa, then the muscle layer, before it can reach the nerve that cries out in pain. Until that moment, everything it does—absorbing nutrients, dividing, expanding—triggers no alarm in the brain.

It’s like a burglar rummaging through your living room for three hours while you sit in the bedroom with noise‑canceling headphones on, reading a book, completely unaware.

Why do those early “signals” get ignored?

Early-stage colorectal cancer does produce signals. The problem is they look exactly like everyday minor ailments.

Blood in the stool. Seeing red in the toilet bowl, most people’s first thought is “my hemorrhoids are acting up again.” That judgment takes about 20 seconds. Then flush, stand up, wash hands, and move on with the day.

Fatigue and weight loss. Blamed on “I’ve been overworked lately” or “perfect time to shed a few pounds.” The body slowly adapts to anemia from chronic微量 blood loss. Today a little more tired than yesterday; tomorrow a little more than today—the change is so subtle that no one notices.

Changes in bowel habits. Occasional diarrhea, occasional constipation—who hasn’t had that? No one makes a doctor’s appointment because “I went twice yesterday and not at all today.”

Vague abdominal discomfort or dull pain. Comes and goes, moves around, doesn’t stay in one spot. A warm drink and a little rubbing, and it passes.

Unexplained anemia. Paler complexion, brittle nails, getting winded on stairs more than before—most chalk it up to “just getting older.”

By the time the signal is no longer a “minor issue,” the situation is no longer minor.

When a tumor grows large enough, it either blocks the intestinal lumen—food can’t pass, gas can’t escape, causing severe abdominal pain, vomiting, and inability to pass stool or gas—or it perforates the intestinal wall, allowing bacteria from the gut to flood the abdominal cavity, triggering diffuse peritonitis.

Intestinal obstruction and gastrointestinal perforation—once these two complications appear, the patient is usually already at Stage III or even Stage IV. This is no longer a slow drain on the body; it’s a sudden stomp on the accelerator. Many patients don’t die from cancer spread—they die from septic shock caused by complications.

So what can we do? The only answer is not to wait for signals.

In The Devotion of Suspect X, Higashino wrote about a common cognitive trap: “It looks like a geometry problem, but it’s actually a function problem.”

Colorectal cancer diagnosis follows the same logic—it looks like a symptom problem, but it’s actually a timing problem. If you wait for your body to sound the alarm before going to the hospital, you’re giving it ten years to slowly set up its trap, only to flip the table at the very last moment.

The one tool that can see through this trap before it’s fully set is the colonoscopy.

A colonoscopy can see every inch of the intestinal lining. More importantly, it doesn’t just see—it can act. When it finds adenomatous polyps (precancerous lesions for colorectal cancer), it can remove them on the spot. It’s like a detective entering the crime scene before the crime happens, catching the culprit while he’s still casing the place.

Colorectal cancer is one of the most preventable, most easily detectable, and most treatable gastrointestinal cancers. The five‑year survival rate for early‑stage disease is over 90%; for late‑stage, it plummets to around 10%.

That 90‑point chasm can be closed with a single examination.

Who should get screened, and when?

For average‑risk individuals: Start with a first colonoscopy at age 50. If results are normal, repeat every 5 years. An annual fecal occult blood test is also a non‑invasive and effective preliminary screening tool.

For high‑risk individuals (meeting any of the following criteria):

• A first‑degree relative with a history of colorectal cancer or polyps

• Personal history of ulcerative colitis, Crohn’s disease, or colorectal adenomas

• Long‑term diet high in fats and proteins, low in fiber

• Long‑term smoking, heavy alcohol consumption, or obesity

• Age 40 or older

For high‑risk groups, screening should start at age 40, or even earlier, with intervals shortened to every 1–2 years.

Daily prevention is equally straightforward: eat more whole grains and fresh fruits and vegetables, letting dietary fiber do the deep cleaning for your gut; cut back on smoked, cured, and deep‑fried foods; quit smoking, limit alcohol, exercise regularly, and maintain a healthy weight; and for those with a history of enteritis or polyps, adhere to scheduled follow‑ups. None of this is complicated. The difference between doing it and not doing it isn’t luck—it’s follow‑through.

A final word for those who consider themselves “healthy”

Higashino once wrote: “There are two things in this world that you cannot look at directly: one is the sun, and the other is the human heart.”

Perhaps we need to add a third: the silence inside your own body.

Your body won’t leave clues like a killer in a novel, allowing you to slowly deduce the answer. It will simply, quietly, break down day by day, until one day it throws all the truth in your face at once. And by then, there’s usually no plot twist left.

Instead of waiting for a signal, take the initiative and look.

If you’re over forty, or if someone close to you is in that age bracket, treat this article as a screening invitation. Forward it to them with a note: “Let’s book a colonoscopy together. I’ll go with you.”

Writing can dissect human nature. But life doesn’t require deduction. It requires only hard evidence, one examination, and one decisive action.