Nasopharyngeal cancer in primary care: a case-control study using electronic patient records.
Problem
Nasopharyngeal cancer is rare; around 230 cases are diagnosed in the UK annually. There are currently no specific referral recommendations for nasopharyngeal cancer within the National institute for Health and Care Excellence (NICE; NG12) cancer guidelines. The clinical prodrome of nasopharyngeal cancer, separate from grouped head and neck cancer features, is unknown. Therefore, this study aimed to identify and quantify the individual and combined risk markers for nasopharyngeal cancer in UK primary care patients.
Approach
This was a matched case-control study of patients aged ≥40 years using UK primary care electronic patient records. Cases were matched with up to 5 controls for age, sex and general practice. Putative clinical features of nasopharyngeal cancer were identified in the year before diagnosis via literature search, online databases and patient self-reported symptoms. Clinical features associated with cancer were assessed using conditional logistic regression. Positive predictive values (PPVs) for each feature were calculated for the consulting population.
Findings
Interim findings - 74 cases diagnosed with nasopharyngeal cancer between 2000 and 2009 and 330 matched controls (practice, sex and age) were studied. Four independent and clinically relevant features were associated with nasopharyngeal cancer: head and neck lump, odds ratio 69, (95% confidence interval 2.1 to 162); thrombocytosis 27, (3.3 to 225); epistaxis, 18 (2.0 to 162), and otalgia 17 (3.0 to 92). All P values were <0.01. Individual positive predictive values were <1%: epistaxis and head and neck lump, 0.03%; thrombocytosis and otalgia 0.01%.
Consequences
This is the first study to investigate the clinical features of nasopharyngeal cancer in primary care. Given the rarity of the cancer and the resulting low PPVs, GPs won’t be referring patients based on these features alone. However, we now know the features of this rare cancer. This will be useful to GPs who can use their experience and intuition to spot the patient who may warrant referral to an ENT specialist for suspected nasopharyngeal cancer. As a result, patients may benefit from earlier referral, potentially impacting on their stage of cancer at diagnosis.