Eight ‘red flag’ cancer symptoms you should never ignore

Are you experiencing sudden unexplained weight loss? Or a lump that has suddenly emerged? If so, it is worth seeing the doctor to get the all-clear, just to make sure these symptoms are not a sign of something more sinister.

A new poll from Cancer Research UK has revealed that half of people with possible cancer symptoms leave it for more than six months before contacting their GP, despite having noticed worrying changes to their body. The survey of nearly 2,500 people found that just 48 per cent of people who had experienced a so-called “red flag” symptom subsequently sought medical advice, a finding which cancer experts describe as concerning.

“We know that early diagnosis is so important with all types of cancer,” says Julie Sharp, head of health and patient information at Cancer Research UK. “Treatment at the very earliest stage means it’s more likely to be successful. But if people are delaying and not going to their GP soon enough, it means that cancer has a greater chance of progressing and could be harder to treat when it’s found.”

Here are some of the most common red flag symptoms: 

1. Sudden weight loss

Cancer experts say that an unexplained weight loss – of a stone or more – which is not related to any dieting or exercise regime, can be an early-warning sign that something is amiss. According to the American Society of Clinical Oncology, around 40 per cent of patients say that they had unexplained weight loss when they were first diagnosed.

Helen Coleman, professor of cancer epidemiology at Queen’s University Belfast, explains that weight loss is not indicative of any type of cancer in particular, but is the result of the general impact tumours can have on the body’s metabolism.

“When there’s a tumour growing, it sucks up almost all the calories that you’re eating to feed itself,” she explains. “That’s why it can lead to this unintentional weight loss.”

Sharp says that over-65s are more likely to try and explain away subtle symptoms such as sudden weight loss with the fact that they are older and therefore eating smaller meals, instead of looking at this as a possible problem. “People really need to listen to their bodies,” she says. “Because often they know that something doesn’t feel natural, and it’s important to then act on that.”

2. An unusual mole

The first sign of melanoma skin cancer can be a mole which changes size, shape or colour. While normal moles tend to be oval-shaped, a uniform colour and no more than 6mm in diameter, melanoma moles are subtly different.

To identify them, the Mayo Clinic advise thinking of the letters ABCDE. “A” refers to an asymmetrical shape, “B” means an irregular border, “C” points to changes in colour or an uneven colour distribution, “D” is diameter (as malignant moles tend to be larger than 6mm), and “E” is for evolving, as changes in size, colour or shape can indicate a problem, as can new itchiness or bleeding.

“Melanoma skin cancer is a strong example of this point about going to the doctor early,” says Dorothy Bennett, professor of cell biology at the University of London. “The key sign in adults is a new or old mole that is growing, as well as being larger than your other moles, itching, bleeding, irregular or fuzzy borders, and some differently coloured areas. The more signs, the more likely it is a melanoma.”

Bennett says that it is particularly important to detect melanomas early, as 99 per cent of people will survive for five years if the cancer is detected early. In comparison, if the cancer has spread to other parts of the body by the time it is diagnosed, only 53 per cent of people will survive a year.

3. Difficulty swallowing

Discomfort while swallowing, particularly when eating meat, bread or raw vegetables, can be an early-warning sign of different head and neck cancers, such as oesophageal cancer, especially when combined with symptoms like frequent and intense bursts of heartburn, coughing and a feeling of pressure in the chest. This can be due to the presence of a tumour blocking the progress of food down through the oesophagus and into the stomach.

“The digestive cancers tend to have digestion-related symptoms such as persistent heartburn which can affect people more at night-time,” says Coleman. “We often hear stories from patients who have a feeling like food is stuck just above their stomach.” 

4. Bloating

Seventy per cent of ovarian cancers are not detected until the disease has reached an advanced stage, meaning it tends to be dubbed “a silent killer”. Because of this, scientists at the University of Washington have identified six potential warning signs of the disease.

One of these is bloating, which can occur if the cancer has spread to the peritoneum – the membrane which surrounds your abdominal organs – irritating it and causing it to produce more fluid than normal.

Anyone experiencing bloating, increased abdominal size, feeling full quickly, difficulty eating and bouts of pelvic and abdominal pain which occur more than 12 times a month should seek urgent medical attention.

“Based on these six symptoms, we have been able to detect ovarian cancer in 60 per cent to 85 per cent of the patients studied, a range similar to that achieved through diagnostic blood tests,” says Barbara Goff, professor of obstetrics and gynaecology at the University of Washington. 

Bloating might also be caused by less worrying issues such as having a lot of gas in your gut due to fizzy drinks or eating certain vegetables, or digestive issues, but it's always worth seeing your doctor.

5. Blood when you go to the loo

Blood in your poo can be a sign of haemorrhoids, but it can also be an early sign of bowel cancer. So how to tell the difference? 

A key tell-tale sign is the colour of the blood. If it is bright red, fresh blood, it is more likely to be haemorrhoids, a condition which usually gets better on its own. However if it is a tumour, the blood will have come from higher up in the bowel, and is a dark red or black colour which makes your poo look a bit like tar.

Bowel cancer tends to come with a constellation of symptoms which can also include changes in your normal bowel habits such as a desire to poo more often and pain in your abdomen, as well as weight loss.

6. An unusual lump

Finding a new lump in your body can be a scary moment. But most of the time it will be harmless, probably the consequence of a skin condition which has caused excess oils to accumulate in the body’s pores. 

Oncologists describe not-so-serious lumps as being soft, located in the fat layer of skin and can move and change form when you touch them.

Instead, cancerous lumps – the ones which can be felt from the outside can appear in the breasts, testicles, neck, arms and legs – tend to be large, hard, painless to the touch, and steadily grow in size over a period of weeks and months.

7. A persistent mouth sore

Sharp says that a mouth sore which is still present after two weeks is cause to see a doctor as it can be a sign of mouth cancer.

The Head and Neck Cancer Foundation are keen to raise awareness of signs of oral cancer because early diagnosis can increase survival rates by 93 per cent. Other tell-tale signs are a persistent ulcer which is also associated with a burning sensation, an odd feeling on the lip or tongue, and bleeding or numbness in the mouth.

8. Fatigue

Extreme fatigue which does not improve with rest is one of the most common early signs of any cancer prior to diagnosis. Some patients describe it as akin to an overwhelming exhaustion which does not get better with a good night’s sleep, and can come with feelings of physical weakness and brain fog.

Coleman says that this is because of the energy demands of cancer cells. “Cancer is a real energy drainer,” she explains. “Essentially a tumour thrives on energy, and will use up your resources and leave the person feeling very tired.”