Image copyright SPL

GPs with patients who have a persistent sore throat, combined with shortness of breath, trouble swallowing or earache, should consider cancer as the cause, according to new research.

Currently, it is recommended patients with persistent hoarseness or an unexplained neck lump are investigated for throat or laryngeal cancer.

However, Cancer Research UK's Weilin Wu said patients should not be alarmed.

"A sore throat on its own wasn't linked to laryngeal cancer," he said.

"But importantly, this study also provides the best evidence to date to support the current recommendation to refer older patients with persistent hoarseness."

The larynx is part of the throat found at the entrance of the windpipe that helps you breathe and speak.

In the UK, there are around 2,000 new cases of laryngeal cancer each year.

The research, led by the University of Exeter, looked at patient records from more than 600 GP practices and studied 806 patients diagnosed with cancer of the larynx and 3,559 control patients. It is published in the British Journal of General Practice.

Lead author Dr Elizabeth Shephard said it was the first real look at all the symptoms that might be important for laryngeal cancer.

"The significance of the study really is that we've found that hoarseness is important for laryngeal cancer, but significantly the risk of having laryngeal cancer greatly increases when it's combined with a recurrent sore throat," she said.

Laryngeal cancer

More common in men

Strongly linked to tobacco and alcohol use

Early diagnosis improves outcomes

Radiotherapy, surgery and chemotherapy are the main treatments

If the cancer is advanced, the patient may have to have surgery to remove part or all of the larynx

These patients will no longer be able to speak or breathe in the usual way

They will breathe through a permanent hole in their neck (stoma) and will need additional treatment to help restore their voice

This may include a throat implant or an electrical device you hold against your throat to produce sound

Source: NHS Choices

One of the study authors, Prof Willie Hamilton, was the clinical lead for the current guidelines from The National Institute for Health and Care Excellence (NICE).

He said their research is important because it "has shown the potential severity of some symptom combinations previously thought to be low risk."

"When NICE guidance for cancer investigation was published, there was no evidence from GP practices to guide this - nor to inform GPs," he said.

Image copyright SPL Image caption Smoking can increase the risk of cancer of the larynx

But he points out they are not talking about just any sore throat - "the sore throat has to be significant enough to go to the GP".

"We're all used to sore throats, but the sore throats that are reported to GPs are already unusual because it's gone outside the patient's norms."

And it is the combination of persistent symptoms - sore throat, hoarseness and breathing or swallowing problems - that could be a warning sign, he said.

Dr Shephard said the study will feed into the NICE guidelines when they are updated.

"It's vital for selecting the right patients for referral. If we get people earlier we can then diagnose the cancer at an earlier stage and they will have access to the right treatment."