A symptom combination of sore throat plus either difficulty swallowing or breathing or ear pain is associated with a heightened risk of laryngeal cancer, suggests research* published in the British Journal of General Practice.
These combinations are not outlined in current National Institute for Health and Care Excellence (NICE) guidance on referral, highlight the researchers, but are associated with a positive predicted value (PPV) of more than 5%.
This is important because NICE guidance was based on clinical consensus, in the absence of primary care studies, say the researchers.
More than 1,700 people are diagnosed with laryngeal cancer every year in England. And a recent UK study of 28 cancers identified laryngeal cancer as having the fifth longest time from diagnosis in primary care to referral.
The lack of specific visible or palpable signs for laryngeal cancer means that GPs have to refer based on presenting symptoms alone, say the researchers.
In a bid to quantify the predictive features of laryngeal cancer in primary care, the researchers used data from patients over the age of 40 whose details had been entered into the UK’s Clinical Practice Research Datalink.
Clinical features of laryngeal cancer which had prompted patients to see their GP in the year before diagnosis were identified and their association with cancer assessed. Positive predictive values (PPVs) for each clinical feature were calculated for those aged 60 and older.
In all, 806 patients who had been diagnosed with laryngeal cancer between 2000 and 2009 and 3,559 healthy patients matched for age and sex were included in the study.
The analysis showed that 10 features were significantly associated with laryngeal cancer: hoarseness; sore throat and reattendance for sore throat; difficulty swallowing; ear pain; reattendance for breathing difficulties; mouth symptoms; recurrent chest infections; insomnia; and raised levels of inflammatory markers.
Reattendance for sore throat was associated with almost an 8-fold odds of being diagnosed with laryngeal cancer, while difficulty swallowing was associated with a 6.5-fold odds of a diagnosis, compared with patients without these symptoms.
The odds were slightly lower for ear pain (5); reattendance for breathing difficulties or mouth symptoms (nearly 5); recurrent chest infections (4.5); insomnia (nearly 3); and raised inflammatory markers (2.5).
Hoarseness had the highest individual PPV of 2.7%. This risk rose to more than 3% when hoarseness was combined with: swallowing difficulties, mouth symptoms, insomnia, ear pain, or recurrent breathing difficulties. The highest PPVs were for hoarseness with sore throat (12%) or raised inflammatory markers (15%).
Symptom combinations currently not included in NICE guidance were sore throat plus either swallowing difficulties, breathing difficulties, or ear pain, for which PPVs were more than 5%.
However, no association between neck lumps and laryngeal cancer was found. This might simply reflect the rarity of laryngeal cancer presenting with regional spread, say the researchers, who nevertheless warn that unexplained neck masses are high-risk symptoms for lymphoma, and warrant referral on that basis.
“These results expand current NICE guidance by identifying new symptom combinations that are associated with laryngeal cancer,” write the researchers. “[They] provide new evidence that GPs should consider relevant when ascertaining whether to refer a patient for suspected laryngeal cancer.”
* Shephard E, et al. Recognising laryngeal cancer in primary care: a large case-control study using electronic records. Br J Gen Pract 2019; 69 (679): e127-133.