Validation of self-reported help-seeking, and measurement of the patient interval, for cancer symptoms: an observational study to inform methodological challenges in symptomatic presentation research

Background
To improve earlier presentation with potential symptoms of cancer, accurate data are needed on how people respond to these symptoms. It is currently unclear how self-reported medical help-seeking for symptoms associated with cancer by people from the community correspond to what is recorded in their general practice records, or how well the patient interval (time from symptom onset to first presentation to a health-professional) can be estimated from patient records.

Method
Data from two studies that reviewed general practice electronic records of residents in Scotland, (i) the ‘Useful Study’: respondents to a general population survey who reported experiencing symptoms potentially associated with one of four common cancers (breast, colorectal, lung and upper gastro-intestinal) and (ii) the ‘Detect Cancer Early’ programme: cancer patients with one of the same four cancers. Survey respondents’ self-reported help-seeking (yes/no) was corroborated; Cohen’s Kappa assessed level of agreement. Combined data on the patient interval were evaluated using descriptive analysis.

Results
‘Useful Study’ respondents’ self-report of help-seeking showed exact correspondence with general practice electronic records in 72% of cases (n = 136, kappa 0.453, moderate agreement). Between both studies, 1269 patient records from 35 general practices were reviewed. The patient interval could not be determined in 44% (n = 809) of symptoms presented by these individuals.

Conclusions
Patient self-report of help-seeking for symptoms potentially associated with cancer offer a reasonably accurate method to research responses to these symptoms. Incomplete patient interval data suggest routine general practice records are unreliable for measuring this important part of the patient’s symptom journey.