Sir,In their discussion Lyratzopoulos et al (2003) make the crucial point that they
were not able to examine whether prolonged values of either the primary care interval or the
number of pre-referral consultations were either justifiable or preventable. We also wish to
question the widely held assumption that optimum care necessitates correctly identifying and
referring a patient with serious illness (cancer) during the first consultation? This
implies that reviewing a patient over time may cause harm as a consequence of delayed
referral and subsequent diagnosis.One of the most important diagnostic tasks performed by general practitioners is
discriminating between the majority of patients with minor, usually self-limiting illness
and the minority with serious disease such as cancer. We have previously argued that the
test re-test opportunity afforded by reviewing a patient maximises the gain in certainty in
low prevalence settings such as general practice, the time efficiency principle (Irving and Holden, 2013). Arranging a follow-up consultation when
presented with a patient with non-specific symptoms that may indicate major pathology
frequently provides an opportunity to safely and efficiently reduce the number needed to
predict (the number of patients that need to be examined in order to predict a diagnosis of
a given cancer in one patient).The authors provide two examples of ‘more challenging cancers without specific
symptoms'.One GP can expect to see a new case of each during their whole professional career.
Furthermore, the median primary care intervals for these two cancers were 14 and 21 days,
respectively. This suggests that GPs may well be performing effectively by picking up these
difficult cancers by using the time efficiency principle and further improvement may thus be
extremely hard to achieve. Therefore, the opportunities to improve the performance of GPs
may be remote. The cost of additional investigation and referral in these circumstances may
also far exceed any possible benefit to patients.We therefore consider that the key issue is ‘what is the optimum number of
consultations required to safely and efficiently reduce the number needed to predict while
keeping delays below biologically plausible limits for individual cancers?' We should
be open to the possibility that this may paradoxically be more than one consultation.
Indeed, we estimate that optimum range will often be about 1–3 consultations based on
the evidence presented in this paper.