Cancer doesn't usually make a lot of noise. The colon is one of the mumblers and one of the confusing mumblers is when you go from diarrhoea to constipation in the same week, and sometimes the same day.

Many people have a sort of common tendency to blame the digestive upset on something that they ate the night before, or to work stress, or to a sudden flare-up of what a doctor used to loosely refer to as "irritable bowel". And if that bit of folklore is true for long enough, then it's exactly the opportunity colon cancer needs.

If the gut alternates between constipation and diarrhoea and the condition will not clear up, it indicates that something is blocking the gut, possibly a tumour that produces a partial blockage and through which the faecal matter has to pass. First, the body backs up behind the blockage and later, it makes up for it by pushing the liquid around the blockage. The consequence is a confusing pattern of hard, difficult stools at one time and watery stools at another, and most people, understandably, think that they are suffering from a digestive disorder.

This difference, functional versus mechanical, is one of the most important misreadings, in gastroenterology in the present day. The worst case scenario for diagnostic delay is when the diagnosis of IBS is made, and symptoms are managed without further investigation for months. And it does happen with a frightening regularity.

How a tumour affects your bowel.

Imagine your digestive track as a well-oiled trail. As a growth begins to grow in the colon, it physically interferes and alters the normal flow. When there is constipation, the stool attempts to move past this obstruction and backs up causing a traffic jam, or less stool output and harder stool to pass. In diarrhoea, the body attempts to increase the force of the liquid stool, to move the blockage. This may manifest as sudden onset of watery diarrhea, followed by constipation as the obstruction persists to cause problems.

One other important physical symptom that people often ignore is that poop is thinner than normal – sometimes referred to as pencil thin. When stool gets past the tumour, it may get pushed into a pencil-like shape. This is a very specific clue that there is a physical blockage of the lumen of the colon.

Diarrhoea can also occur because the tumour irritates the lining of the colon, causing inflammation and more mucus to be produced which causes diarrhoea in a different way. So for some presentations, you can have both the obstruction effect and the inflammatory effect at the same time, and that's why you see some patients reporting a feeling of not feeling done after going to the bathroom.

The persistence factor is the clinically important bit! Usually, one day of not going to the bathroom is not a problem. However, if these adjustments persist for a few weeks and turn out to be “the new normal” then it is clear that something has structurally changed.

The reason why it continues to be confused with IBS.

Cramps, bloating, gas and periods of diarrhoea and constipation are symptoms of both IBS and colon cancer. It's not a superficial overlap, which is part of the reason for the understandability and the dangers of the diagnostic error.

It is less a question of which kind of symptom is involved, and more of how it behaves clinically. Colon cancer symptoms tend to be more noticeable and include bleeding, sudden weight loss and sudden bowel changes. In contrast, however, IBS tends to have identifiable triggers some foods, menstrual cycles, stress events and symptoms tend to improve or fluctuate. Symptoms of colon cancer, if present, go from mild to severe.

Although people with IBS do not usually wake at night, some people may experience pain or urgency from colorectal cancer at night. May be an issue if diarrhoea or cramping occurs during sleep several times. It's an element that doesn't occur to most patients and doctors to discuss, since it happens at night.

The misdiagnosis issue is not a theoretical one. There are plenty of news reports of individuals who were diagnosed with IBS or haemorrhoids and were really suffering from colorectal cancer. This is especially evident in younger patients. If a 32-year-old patient presents to a clinic with variable stool frequency, and no history of cancer in the family, the mind will use the statistic that that is not likely to be cancer, which leads the clinician astray.

IBS does not lead to an increase in one's risk of colon cancer, but it is important to be aware of the possibility of colon cancer and not dismiss certain symptoms as part of one's irritable bowel syndrome. Symptoms that should be assessed in IBS patients to investigate other causes like colon cancer include sudden weight loss, narrowing of stool and rectal bleeding.

A disease invading an area in which it is not normal.

That's where the medical and demographic issue comes in. For decades, colorectal cancer was viewed as an “old person's disease” and screening was meant for people over the age of 50. This type of framing seems dated these days.

According to the 2025 American Cancer Society report, incidence rates have been declining by approximately 1% per year for people over the age of 50, but have actually been rising by 2.4% per year for those under the age of 50 for the same time period.

The study, published in the Lancet Oncology, showed a definite rise in colorectal cancer detection rates in younger adults. From 2013 to 2017, incidence rates rose in 27 of the 50 countries included in the analysis for people under the age of 50. The researchers think that this is a global trend that mirrors the lifestyle in general, including consuming different things and having a less active lifestyle.

This is not the case in India alone. The Global Cancer Observatory estimates that in 2022, there were approximately 43,360 new male and 26,678 new female colon cancer cases in India. An Indian multicenter study of young adults with colorectal cancer showed that 67% were between the ages of 30 and 39 years and there were no significant gender differences. There was a high prevalence of adenocarcinoma with signet ring differentiation, a more biologically aggressive tumour type, indicating more biologically aggressive disease in this younger population.

In India, the median age of CRC presentation is around 50 years as opposed to the western patient population. Most of these are advanced cases which lead to a poor prognosis. No formal guidelines exist for cancer of colon in India. Those last words should have some substance! When doctors are presented with a cancer burden that is increasing in the country's working age population, there is no national strategy to guide them.

The hidden side of the economy

Cancer in public health discussions is usually very clinical survival rates, staging, treatment protocols. Even when the economic aspect is not much talked about, it plays as much a role as any surgical procedure in determining the outcome.

The median total cost of CRC care in India was 407,508 Rupees (about $5,340 USD), with out-of-pocket costs being the largest contributor, with the patient paying a median of 330,277 Rupees ($4,328 USD). That isn't a cost, for most Indian homes, it's a financial catastrophe.

In India the monthly out-of-pocket expenditure on cancer was found to be 37% to 49% of the monthly consumption expenditure for inpatient and outpatient care, respectively. Households relied on their own income and savings to pay for care, and hardship financing was faced even by higher income quintile patients.

The total economic cost of colorectal cancer is about 19 billion euros per year in Europe, and is likely to significantly rise in the next few years. By 2030, the number of new cases of colon cancer and deaths are estimated to rise by 60% globally, reaching over 2.2 million and 1.1 million, respectively.

The productivity loss is a separate book. The economic implications of a 35-year-old woman who has colorectal cancer are the costs of treatment, but not just the cost of treatment it is 25-30 years of lost earning potential, care and support labour diverted from caring for children or other dependants, and the ripple effects. In 2017 international dollars, the global economic burden of cancer in the years 2020 to 2050 was estimated to be $25.2 trillion. This is a substantial proportion of the 3rd most common cancer worldwide, which is colorectal cancer.

When it's time to stop blaming it on stress

There are some pretty well accepted clinical signs that change a bowel grievance from a common affair to a condition that requires further investigation. Bright red blood in the stool or dark, tarry blood in the stool, no matter how certain a person is that it's haemorrhoids, is never normal. Dark or tar-like stool could indicate blood in the stool and could be a sign of gastrointestinal tract bleeding.

Similarly, weight loss that does not have an explanation, such as losing kilograms despite no change in eating or activity, is a red flag that can't be ignored. So is fatigue that does not respond to sleeping and is usually a sign of anaemia caused by the slow bleeding of the tumour over time.

If these symptoms persist for several days, consult a health care professional. But don't feel shy if blood shows up in the stool, weight loss occurs when you aren't trying or fatigue just doesn't go away with any amount of rest.

The problem in India, as well as most of the developing world, is that these discussions occur at a late stage in the clinical work-up; gastroenterologist referral is not always easy, and primary care physicians are also busy and take a statistical approach most young people with gut problems don't have cancer. This is so at the aggregate level. Not true for one person who is seated at the desk.

A sensible response will take the following form

A few minimum thresholds should be considered as part of the clinical pathway in the presence of persistent alternating bowel habits: the colonoscopy or flexible sigmoidoscopy should be considered if symptoms persist for more than 4–6 weeks with no clear functional cause; faecal occult blood testing is an easily accessible initial screening tool; and a targeted review of family history should be considered as hereditary colorectal cancer syndromes–such as Lynch syndrome and familial adenomatous polyposis–can present aggressively at the third and fourth decades of life.

Record when the changes started and record any changes in lifestyle or diet. If constipation lasts longer than two weeks, see a doctor to identify its cause.

The more significant structural measure lower age cut-off than recommended in Western countries, because of the pattern of presentation in the country, national screening guideline for India has been a national imperative and has been called for years by the Indian Council of Medical Research and Indian Cancer Society. The awareness of an increasing number of colorectal cancers should be on the national agenda. The suggestion, which appeared in a peer-reviewed journal, has yet to be translated into policy.

Gut is not a showy part. It does not give sharp and clear alarms. When something is really off, what it does is cause some sort of ongoing, low level, disruption of the routine of everyday life: stool changes, habit changes, a general sense that something is different. People generally wait to do something until the drama unfolds. It is seldom ever found in the colon until it is too late for the drama to be avoided.

The stimulus to which a response is required is not pain that doubles you over. It's the vague, not-so-urgent feeling that your tummy isn't functioning as it should. Now is the time for opportunity not the time after.