Cancer is a large group of diseases that can start in almost any organ or tissue of the body when abnormal cells grow uncontrollably, and go beyond their usual boundaries to invade adjoining parts of the body. According to the World Health Organization (WHO), it is the second most common cause of death globally, accounting for millions of deaths every year. Lung, prostate, colorectal, stomach and liver cancer are the most common types of cancer in men, while breast, colorectal, lung, cervical and thyroid cancer are the most common among women. However, these are not necessarily the deadliest forms of cancer.

What makes cancer the deadliest depends upon how many people have it and what percentage of those people actually survive. Cancer researchers determine this on the basis of five-year relative survival. This is the percentage of people who are expected to survive the effects of a given cancer, excluding their risk of other possible causes of death, for five years past a diagnosis. It is also important to note that what makes cancer really deadly is that practically no cure for it. A cure for cancer would imply that there are no cancerous cells remaining in the body.

Here are the 5 deadliest cancers in the U.S., according to SEER five-year relative survival data for cases diagnosed between 2014 and 2020.

1. Pancreatic cancer occurs when cells in your pancreas, a gland in your abdomen that aids digestion, mutate and multiply out of control, forming a tumour. Major risk factors include smoking, obesity, diabetes, chronic pancreatitis, certain genetic mutations and environmental chemical exposure.

2. Esophageal cancer develops in the oesophagus, which is the tube that connects your throat to your stomach.

3. Liver cancer and intrahepatic bile duct cancer originate in the liver or bile ducts, often linked to hepatitis infections, heavy alcohol use, obesity, and aflatoxin exposure.

4. Lung and bronchus cancer primarily caused by smoking, secondhand smoke, and environmental pollutants, affects the lungs and airways, making it the leading cause of cancer death in the US.

5. Acute myeloid leukaemia (AML) is an aggressive blood and bone marrow cancer that progresses rapidly, often linked to genetic mutations, radiation exposure, and certain chemicals.

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Low-dose CT (LDCT) screening of people at high risk based on age and smoking history can reduce lung cancer deaths and advanced-stage disease, according to an International Agency for Research on Cancer (IARC) working group.

Speaking to HealthandMe, Dr Abhishek Shankar of AIIMS New Delhi, the only Indian author among the 23 experts from 17 countries involved in the IARC review, said India needs to generate its own screening evidence.

The review was published in The New England Journal of Medicine as part of IARC WHO Handbook 21.

India Should Not Wait For A Perfect Model

Dr Shankar, a lung cancer specialist, said India needs to generate its own screening evidence while ensuring high-risk people have access to screening and follow-up care.

“India should not wait for a perfect screening model and there is a need to generate Indian evidence while ensuring that those at highest risk have access to lung cancer screening and care pathways for screen positive cases,” he said.

Dr Shankar is leading the Indian Lung Screening Trial (ILST), which is assessing risk-based lung cancer screening across 10 centers in India.

Also read: Never Smoked, Still Got Lung Cancer? Rare Gene Mutation Linked To Over 60x Risk

Who Should Undergo LDCT Screening?

The evidence mainly covers people aged 50 to 80 with a substantial smoking history, typically 20–30 pack-years or more. Studies involving former smokers generally included those who had quit within the previous 10–15 years.

In India, people aged 50 to 80 who have smoked at least 20 pack-years and are current smokers or quit within the past 15 years can contact ILST about screening under the trial.

“High-risk smokers should be encouraged to participate in organized screening rather than opportunistic CT scanning, with appropriate nodule management, follow-up and smoking-cessation support,” Dr Shankar said.

What Did The Trials Show?

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In the US National Lung Screening Trial, LDCT was linked to a 16% lower relative risk of lung cancer death at seven years compared with chest X-rays. The European NELSON trial also found lower lung cancer mortality among men screened with LDCT at 10 years.

IARC classified LDCT as Group A, indicating established evidence that it reduces lung cancer mortality and stage III or IV disease. Chest X-rays, with or without sputum examination, were classified as Group C, as a mortality benefit could not be established.

What Are The Risks Of LDCT Screening?

LDCT is not meant for everyone. Across studies, false-positive rates ranged from 1% to 42%. Among those with false-positive results, 5% to 32% underwent an invasive procedure, with complications reported in 10% to 22% of those procedures.

The review also estimated that 3% to 26% of lung cancers detected in randomized trials could represent over-diagnosis.

The IARC group stressed that screening requires more than CT scans, including risk assessment, nodule management, follow-up, smoking-cessation support and adequate healthcare capacity.

“India has an opportunity to build an equitable, affordable, locally relevant lung cancer screening pathway and ILST can provide the evidence needed to guide that future,” Dr Shankar said.

Doctors may soon be able to determine a brain tumour’s type right during the surgery. Doctors remove a tissue sample during surgery to analyse the tumour. Patients undergoing surgery for brain tumour may not have to wait days or weeks to find out.

A new rapid genetic test being tested by the NHS in England promises to shorten the wait time drastically. The technology can find the precise type of brain tumour within about two hours, while the patient is still on the operating table.

Developed by researchers at the University of Nottingham and Nottingham University Hospitals NHS Trust, the test analyses the genetic code of a tumour sample rather than relying only on traditional microscopic examination.

Brain Tumour Diagnosis Takes A Long Time

Brain tumours are not connected to one single disease. There are more than 100 types, ranging from relatively slow-growing tumours to highly aggressive cancers. Knowing the exact type and characteristics of a tumour is important because treatment courses can differ significantly.

Traditionally, doctors take a sample during surgery and send it to a pathology laboratory. The tissue sample is then examined under a microscope. Finding out the tumour type usually takes weeks.

According to an NHS centre, the current average time for a brain tumour diagnosis can be around 26 days, while other reports have estimated up to almost eight weeks in some cases. In case of aggressive tumours, waiting period can be particularly difficult and longer.

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More About The New Test

The rapid genomic test works by analysing a small piece of the tumour which is taken during the surgery and sent to the laboratory, where its DNA is analysed using a shoebox-sized sequencing machine developed by Oxford Nanopore.

Inside the machine, DNA molecules pass through tiny pores. As they move through, the system reads their genetic information and uses the resulting genomic pattern to identify the tumour type.

Marking a significant jump in speed and time taken, the test can help doctors can receive detailed diagnosis during the operation itself instead of weeks.

Also read: Radiotherapy Cuts Risk Of Atypical Meningioma Recurrence By Nearly Half: Lancet Study

Promising Development In Brain Tumour Diagnosis

Not only this test reduces weeks, sometimes months of anxiety, it can also help surgeons make immediate decisions about how much tumour tissue to remove while protecting healthy brain tissue.

Some tumour types require different surgical approaches, and having molecular information immediately could help the surgeon take quick decisions.

A rapid diagnosis can also help patients to begin the appropriate treatment sooner and gain earlier access to clinical trials designed for specific tumour types.

The NHS is piloting the technology to determine how well rapid genomic testing works in routine clinical practice. The initial rollout covers five specialist centres, including Nottingham University Hospitals, University Hospitals Birmingham, Great Ormond Street Hospital, King's College Hospital and Newcastle Hospitals. More centres are expected to be added soon.

The rapid testing is therefore intended to complement the entire diagnostic process rather than make traditional pathology obsolete. If the NHS pilot is successful, rapid genomic testing could eventually make that information available much earlier to brain tumour patients across England.

The early signs of type 2 diabetes could be related to your gut. They may signal a warning risk long before you take a blood sugar test.

New research suggests that changes in the trillions of bacteria living in the gut may accurately predict future diabetes risk.

An analysis of microbiome data from more than 229,000 adults in the UK and US identified hundreds of bacterial changes linked with type 2 diabetes, including changes that appeared before measurable abnormalities in blood glucose.

The findings are being presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Milan.

What Did Researchers Find?

Researchers from the University of Trento in Italy and collaborators in the UK analysed metagenomic data, which involves examining the DNA of microorganisms living in the gut.

The study included 229,025 people, of whom 3,627 had type 2 diabetes, 14,022 had prediabetes and 211,376 had normal blood glucose levels. The average age was 50, and about 74% of participants were women.

After accounting for factors including age, sex and body mass index, researchers identified 789 bacterial species associated with type 2 diabetes.

Of these, 168 were found at higher levels in people with diabetes, while 621 were present at lower levels.

One example was Enterocloster bolteae, which was more abundant in people with type 2 diabetes. In contrast, Romboutsia timonensis was found at lower levels.

Interestingly, 587 of the 789 bacterial species were also associated with unmedicated prediabetes, suggesting that some of these microbial changes may occur before diabetes is diagnosed.

Also read: Diabetes Linked To 55% Risk Of Kidney Disease, Heart Failure Or Death Within 10 Years: Study

Link Between Gut & Blood Sugar

The researchers looked at 135,093 people who had normal blood glucose and did not have diabetes or prediabetes. They also had information about how their blood sugar responded after eating.

Normally, blood glucose rises after a meal and then falls. If it remains elevated for longer than expected, it can indicate that the body's muscles are not responding properly to insulin, an early feature of insulin resistance.

Researchers found that people whose blood sugar remained elevated for longer were more likely to have the gut bacterial pattern linked with type 2 diabetes. The microbiome changes became more pronounced as insulin resistance increased.

Therefore, it was observed that the gut microbiome carried clues about metabolic problems even when standard blood glucose levels were still normal.

Also read: Muscle Loss In Middle Age May Signal Dementia Risk, Study Finds

Future Of Diabetes Testing

Currently, diabetes and prediabetes are diagnosed using tests like HbA1c, fasting blood glucose and oral glucose tolerance tests.

For people who have normal results, doctors generally assess future diabetes risk using factors like age, sex, body mass index and family history. A gut microbiome test is not currently part of routine diabetes screening.

The researchers believe microbiome analysis could eventually provide an additional layer of risk assessment, identifying people who could benefit from earlier lifestyle interventions.

Professor Tim Spector, one of the study's authors, Scientific Co-Founder, ZOE, said, “These latest findings represent a major step forward in understanding how our gut microbiome is linked directly with metabolic disease. Identifying these clear microbial changes before blood sugar levels worsen could lead to earlier intervention with food and lifestyle choices, as well as treatment options, to prevent T2D."

The researchers say that microbiome analysis should not replace existing tests for diabetes or prediabetes. The current findings show associations between particular bacterial patterns and diabetes risk.

The researchers also found that some of the bacteria making up the diabetes-related signature have never been isolated or cultivated in a laboratory and are new in terms of scientific investigation.

Additional research will be needed to assess whether these microbial changes can reliably predict who will develop diabetes and whether changing the microbiome can actually reduce that risk.