Does changing healthcare use signal opportunities for earlier detection of cancer? A review of studies using information from electronic patient records

Abstract

Background It has been proposed that changes in healthcare use before cancer diagnosis could signal opportunities for quicker detection, but systematic appreciation of such evidence is lacking. We reviewed studies examining pre-diagnostic changes in healthcare utilisation (e.g. rates of GP or hospital consultations, prescriptions or diagnostic tests) among patients subsequently diagnosed with cancer. Methods We identified studies through Pubmed searches complemented by expert elicitation. We extracted information on the earliest time point when diagnosis could have been possible for at least some cancers, together with variation in the length of such ‘diagnostic windows’ by tumour and patient characteristics. Results Across twenty-eight studies, changes in healthcare use were observable at least six months pre-diagnosis for many common cancers, and potentially even earlier for colorectal cancer, multiple myeloma and brain tumours. Early changes were also identified for brain and colon cancer sub-sites. Conclusion Changing healthcare utilisation patterns before diagnosis indicate that future improvements in diagnostic technologies or services could help to shorten diagnostic intervals for cancer. There is greatest potential for quicker diagnosis for certain cancer types and patient groups, which can inform priorities for the development of decision support tools.

Examining methodology to identify patterns of consulting in primary care for different groups of patients before a diagnosis of cancer: An exemplar applied to oesophagogastric cancer

“…This method compared the number of consultations between cases and controls in each discrete aggregation period before diagnosis [8]. For a 28-day aggregation period, 96 separate models were run: one for each time-period and multimorbidity burden level.…”

“…These methods analysed data from cases only [8]. We modelled the log of the expected number of consultation-days in the 28-day aggregation period as a function of discrete time before diagnosis.…”

“…Modelling population-level consultation rates, which rise before a cancer diagnosis, may offer a robust alternative to patient-level metrics. Existing methods identify statistically significant deviations in consultation rate, either between groups or from historical trends [8]. Statistical significance depends on effect and sample size; therefore, the time of consultation-rate change may vary with group size or underlying consultation rate.…”

Assessing Ethnic Inequalities in Diagnostic Interval of Common Cancers: A Population-Based UK Cohort Study

“…The index feature was the first feature recorded in the year before diagnosis [30]. Features recorded more than one year before diagnosis are less likely to be caused by cancer [31]. Milestone dates and diagnostic interval: The diagnostic interval (DI) was the time from the date of the index feature to the date of cancer diagnosis [32].…”

Pre-diagnostic clinical features and blood tests in patients with colorectal cancer: a retrospective linked-data study

“…Existing evidence demonstrates that clinical activities such as consultation rates increase before cancer diagnosis, suggesting that opportunities may exist to initiate investigations sooner, and therefore expedite diagnosis, in some cancer patients (10)(11)(12). In population-based cohort studies in Denmark, CRC patients had higher overall consultation rates than matched controls as early as 9 months before diagnosis (13).…”