Abnormal symptoms may not always be cancer, but it is important to rule it out by seeing the right doctor, not necessarily an oncologist.
Published Dec 22, 2025 | 7:00 AM ⚊ Updated Dec 22, 2025 | 7:00 AM
Dr Narayanan Subramaniam, lead oncologist
Synopsis: Cancer often begins with ignored symptoms. In an exclusive interview with South First’s Chetana Belagere, Dr Narayan Subramaniam explains why cancer cases are rising in India, the importance of early detection and screening, and how lifestyle factors like tobacco, alcohol, obesity, and pollution contribute. He stresses timely evaluation, evidence-based treatment, and the growing role of AI in improving early cancer diagnosis and care.
Cancer rarely arrives with a warning—more often, it lingers as a symptom you brush off for “just a few more days.”
In a South First interview, Dr Narayan Subramaniam, Lead Consultant (Head and Neck Surgery and Oncology) at Aster Hospitals, breaks down why India is seeing more cancer diagnoses, what doctors mean by “early stage,” who should get screened and when, and why quitting tobacco and alcohol matters—even though the risk doesn’t drop overnight. Excerpts from the interview:
So when you look at the numbers in absolute terms and its growth, it is a bit scary. We know that the number of cancer cases are going up each year, and we also know that’s across multiple cancers. So, there are a couple of parts to that. One of it also is that we are detecting more and more patients. That means, our diagnostics got better and more people have better access to health care and tests. But if you look at the number of patients with cancer going up in a country like India, it’s a little bit alarming.
There are multiple reasons for that. Some are the carcinogens we are exposed to. That teamed with tobacco and alcohol abuse causes huge problem. On the other hand, obesity and air pollution acts as a catalyst. However, the rates of liver cancer and liver transplant has come down as people have been vaccinated with Hepatitis B. Likewise, with HPV vaccines cervical cancer rates are coming down. We are getting better with testing some of these as well.
Abnormal symptoms that don’t go away, or is lasting longer than 2 or 3 weeks deserve an evaluation. It may not always be cancer but it is important to rule it out by seeing the right doctor, not necessarily an oncologist.
Early warning symptoms of cancer are generally focused on the common ones. A few of them are:
Breast cancer: Women can have a breast lump, discharge from the breasts, discolouration of skin around the breast.
Oral Cancer: Lump in ones mouth, white or red patches.
Colorectal cancer: Abnormal passage of stool, passage of blood, alteration in bowel habits, might have either constipation issues or diarrhoea.
Gastric or esophagal cancer: Change in ones diet habit, bloating, long term acidity etc.
Not really. It needs to be evaluated by a doctor or a general physician first. If at all there’s a suspicion of cancer, you will be referred to an oncologist.
Well, patients ask this all the time: “We don’t smoke or drink—why us?” There are two parts to this answer.
First, being healthy still matters because even if cancer happens, a fit person tolerates treatment better and usually has a higher chance of survival. Cancer doesn’t discriminate—but fitness improves outcomes.
Secondly, cancer isn’t just one disease; it’s many. At its core, it begins when DNA gets damaged—through ageing or exposures like tobacco, alcohol, air pollution, and ultra-processed food. The body can repair damage, but when damage outpaces repair, abnormal cells multiply and escape immune control, eventually becoming cancer. Most cancers aren’t inherited: only about 5–10 percent are hereditary; 90–95 percent are sporadic, caused by DNA damage that accumulates over time.
Screening depends on cancer type and risk. For eg:
Breast: Mammography (often after 40; ultrasound in younger women)
Prostate: PSA blood test + digital rectal exam
Oral: Mouth examination (especially for high-risk tobacco/alcohol users)
Lung (high-risk smokers): Low-dose CT chest
Colorectal: Stool test for occult blood (non-invasive)
Most cancer screening would start between the age of 40-50. It varies based on guidelines and risk factors.
Consider quitting as first, because both smoking and drinking damage our DNA. The rate at which our DNA gets damaged varies significantly from person to person. I could smoke one cigarette a day and you can have 10 a day, yet I could end up with cancer earlier than you. This could be because I might have other risk factors that you may not have. So we really can’t quantify that.
This whole concept of “occasional drink” or the “cardio protective effect” that red wine has been debunked. Huge amounts of data from all over the world, hundreds of thousands of patients, and very robust statistics show that alcohol is terrible for you. There’s no safe amount!
Many people don’t realise that quitting tobacco and alcohol doesn’t immediately reduce cancer risk. It can take nearly 10 years for the risk to plateau, meaning only after a decade of complete abstinence does your cancer risk become comparable to that of someone who has never smoked or consumed alcohol.
Absolutely! From a strictly medical perspective, maintaining a healthy weight is crucial—not for appearance, but because excess weight affects every system in the body, much like tobacco does. WHO identifies weight loss as one of the key strategies to prevent cancer. If you are overweight and reduce to a healthy range, you can significantly lower your risk of cancer and other serious diseases.
You have to get it checked! Because the cancerous lumps usually don’t give us symptoms. The ones that are symptomatic, painful, cause irritation, are usually non-cancerous when they’re early. It’s only when a cancer becomes advanced that it gives us a lot of local symptoms. So, any lump that doesn’t go away for more than 2 or 3 weeks, get it evaluated. Evaluation has two components. Usually, it’s some sort of imaging—can be something simple like an ultrasound or a CT or MRI—and a needle test. A needle test pulls out a few cells and that characterises it. Does it look like cancer? Yes or no? If it doesn’t look like cancer, does it look like an infection? Does it look like something else?
‘Early’ means stage. Stage 1 and 2 are early-stage disease. Likewise, stage 3 and 4 are advanced. Stage 4 is often thought of as metastatic, but under stage 4 you have metastatic and non-metastatic—it can be locally advanced and still not spread through the bloodstream.
Cure rates vary a lot by the type of cancer. For example, in thyroid cancer, even if it’s metastatic, patients can still do very well—“your scan looks like a Christmas tree, you will still be alive at 20 years”—because we have remarkable treatments for many cancers.
So we use stage to prognosticate and explain what treatment and survival might look like, but no two patients are alike. We can’t say with certainty that all stage one patients will be cured or all stage four patients won’t—it depends on the treatment they need and the follow-up.
Just as there is self-breast examination, there is also mouth self-examination. Since most of us brush our teeth in front of a mirror, it’s an opportunity to look for early signs of oral cancer. Watch out for:
If any of these symptoms last for more than two weeks, seek medical evaluation. They could indicate oral cancer—even if you have never smoked, used tobacco in any form, or consumed alcohol.
Cancer is a complex disease—it’s not mathematical or binary. The simplest way to understand it is through clinical guidelines, which we adapt with local variations. These guidelines recommend treatments for specific cancers and stages. For example, stage one oral cancer is typically treated with surgery, while stage one vocal cord cancer may be treated with either surgery or radiation.
All of this is supported by strong evidence: clinical trials involving thousands of patients allow us to compare outcomes and determine which treatments provide the longest survival with the fewest side effects.
As oncologists, if we’re honest to ourselves, all of our treatments have side effects. Nobody escapes without any side effects. But the cornerstone for any sensible medical treatment is the risk benefit ratio.
Every treatment, whether it’s surgery, radiation, chemotherapy or targeted therapy, has side effects: mild or severe, sometimes life-threatening.
After surgery, there can be pain, discomfort, or tingling, especially in the mouth. Radiation has local side effects–burning, sunburn-like skin changes, mucositis, difficulty swallowing, and long-term dryness of the mouth. Chemotherapy and targeted therapies circulate through the blood, so they can affect normal fast-growing cells too, kidney function can be affected, bone marrow can be affected, white blood counts can drop, infections can happen, and you can get mucositis. It depends on the treatment and the patient’s general health before treatment.
Absolutely not!
Going to unverified sources of information for comfort. Doctor-hopping for a preferred answer: trying to avoid surgery/chemo by searching for someone who will say otherwise.
I think it’s fascinating. The way AI has changed our worlds has been transformational and the way it can potentially change the way that we deliver healthcare is transformative.
It is already transforming healthcare, especially in specific, well-defined tasks like radiology. But it won’t replace doctors anytime soon because human illness is complex and symptoms vary widely.
In cancer care, AI works best in controlled settings and can act as a safety net, flagging what a tired clinician might miss. In surgery, AI may outperform humans in narrow technical skills, but it still struggles with the real-time decision-making surgeons do.
Where it can make the biggest difference in India is by supporting overburdened doctors, improving efficiency, and potentially reducing complications through smarter guidance and prompts.
We have developed a simple, portable piece of hardware—small enough to carry in a handbag or backpack—that digitises images. While slide scanners already exist and are highly effective, they are expensive and difficult to use outside large hospitals. Our device provides an affordable yet accurate alternative for acquiring these images.
The process is straightforward: we digitize the slides, scan the cells, and use AI to identify abnormal cells. Instead of transmitting entire slide files, which can be several GBs in size, we send only the abnormal cells to a pathologist located remotely. This makes the system efficient enough to run even on basic 3G or 4G networks, without requiring broadband.
We are still refining the technology, but we envision it as a platform for early detection rather than mass screening. For example, if a patient has a lesion in the mouth, a simple brush sample can be processed through the device to deliver results within 5–10 minutes. The goal is point-of-care diagnosis: bringing the equipment directly to patients, providing them with a reliable preliminary assessment, closing the loop, and referring them to the nearest district hospital when needed.
Our aim is to achieve accuracy levels sufficient for insurance companies to accept the test as proof of cancer. We estimate another two years of development before it is ready for widespread use, and we look forward to collaborating with government agencies, primary health centers, and NGOs to make this innovation accessible
Symptoms of cancer can be highly varied and subjective. Even if three people have the same tumor, their experiences may differ greatly depending on pain threshold, lifestyle, and overall health. We are complex systems—what causes severe pain in one person may be tolerable for another.
If you feel something isn’t right, and despite consulting a physician or surgeon the problem persists, don’t ignore it. Make it clear that you want further evaluation. While there is sometimes concern about over-probing, persistent, or troubling symptoms that don’t improve with medication should always be checked again. Go back, ask for more tests, and ensure the issue is properly addressed.
(Edited by Amit Vasudev)
