We have demonstrated a difference between colonic cancer and rectal cancer in the proportion of patients from socioeconomically deprived localities of residence receiving any treatment. Colorectal cancer is usually considered as one entity when considering how diagnostic services work, but there is a developing body of evidence that points to a difference between them.
Recent studies addressing the presentation of colorectal cancer have emphasised that features such as rectal bleeding and microcytic anaemia <10 g/dl identify a minority of patients.11
However, Stapley et al12
found that while presentation with an alarm symptom such as rectal bleeding is associated with earlier stage, presentation with mild anaemia (10–12.9 g/dl), which is likely not to cause symptoms prompting the patient to seek advice, is associated with more advanced stage and worse survival. Symptoms are otherwise non-specific: weight loss, abdominal pain and altered bowel habit. In this study, which avoided recall bias by using primary care records, increasing duration of these was not associated with advancing stage.
In a meta-analysis, a weak association of longer delay and increased survival in colonic cancer was found.13
This was identifiable only after many studies were excluded for various reasons. In a further analysis, the same authors showed that there is a tendency for longer duration of symptoms to be associated with higher stage in rectal cancer but lower stage in colonic lesions.14
This fits with the concept that colonic cancers cause few major symptoms until the flow of faecal matter is impeded by an advanced lesion, whereas prompt diagnosis following bleeding from rectal cancers permits successful intervention. This interpretation is supported by evidence from Denmark, a country with reliance on primary care, which is similar to that in the UK. In the presence of alarm symptoms, survival was shown to decrease with their duration before diagnosis with a trend to the converse for vague symptoms.15
A difference between colonic and rectal cancer, which is consistent with the concept of colonic cancer presenting later has been described by Møller et al
The difference in death rates of patients both with colonic and with rectal cancer was greatest in the first month after diagnosis, more so for colonic cancer. It was markedly greater in the deprived groups as well as being strongly related to age. This is entirely consistent with our finding that patients from deprived areas are more likely to have no active treatment, a phenomenon that is stronger for colonic cancer. However, when death rates in excess of what is expected in the population occurring after the first month are considered, the disadvantage for those from a deprived background as well as older people persists up to 2 years and is stronger for rectal cancer.16
Our finding that for rectal cancer, there is a greater likelihood of being diagnosed at stage 4 associated with deprivation is entirely consistent with this, reduced likelihood survival to 2 years being associated with the visceral metastases that define this stage. Both tumour sites exhibit a minor trend against the most deprived patients with stage 4 disease receiving chemotherapy. It is most likely that this relates to patients being too ill to be treated and as such adds detail to the observations in .
This analysis of observations in colorectal cancer follows the one previously reported in lung cancer.17
They differ in that the NYCRIS Database holds adequate staging information for bowel tumours but not for lung cancer, whereas in the latter tumour site, attainment of a histological diagnosis is a variable that reflects diagnostic activity. The colorectal cancer results show consistent effects of deprivation, but the effect of distance of residence from the diagnosing facility that we saw in lung cancer was not significant in this study.
There are consistent effects that apply to the patients living in the more deprived areas which indicate that in planning the development of services, it is the needs of these patients that should be paramount; it seems that the better off are more able to find their own way through the system. This is supported by the finding that patients from deprived backgrounds are more likely to be admitted to hospital as an emergency18
and indeed to have their first inpatient episode for this diagnosis as an emergency admission.19
On the other hand, increased demand for diagnostic services will mean that the costs of investigation of patients who turn out not to have cancer will increase. They already, it is estimated, account for 35% of the cost of managing colorectal cancer.20
However, the existence of such differences suggests that there is an avoidable cause for them. It is possible that people may experience symptoms without recognising that they signify anything of importance; therefore, the duration is not recalled and the primary care physician's advice is not sought. Encouraging early results have been obtained from one study of measures to promote understanding of early symptoms in deprived communities.21
To do this requires proactive approaches to people in such circumstances because deprived people are not necessarily aware that they have disadvantages in receiving healthcare.22
These cancer sites share the fact that presenting symptoms are ambiguous.
There are a number of caveats to our findings. In order to be comparable to previous work among this cohort, the analysis was based on data for patients diagnosed between 1994 and 2002, a period up to almost a decade ago. In our data set, staging was available for 64.5% of records. In 2009, this figure stood at 65.1% so there has been no significant improvement in staging since then.23
Furthermore, registration personnel collected data from NHS hospital records, a process that is not affected by any of the variables affecting access to care that we have studied. We therefore believe that there are unlikely to be biases associated with incomplete staging. Although pathways from primary care to diagnosis have not been addressed by any changes in practice since our patients were diagnosed, future studies will be need to determine if modifications to policy may alter the associations we observed.
Additional limitations include the fact that our study is cross sectional in nature and therefore we cannot determine if the associations we have observed are causal. Furthermore, the large number of statistical comparisons we have made raises the possibility that some associations may be due to chance. Our measure of deprivation was area rather than individual based and we relied on estimated rather than actual travel times to hospital, although these estimates have been found to be accurate in a previous validation study.9
Nevertheless, a limitation of our analysis of associations with distance is that the most distant travel quartile includes a wide variety of circumstances: the outer suburbs of cities that host major cancer centres, towns that have no hospital and the furthest rural locations. In the future, it will be of interest to evaluate the deficiencies in access in each of these separately.
A new version of the UK Guidance on the diagnosis and management of colorectal cancer has recently been developed.24
It has not addressed those points in the patient's pathway that precede referral to a gastrointestinal specialist; our work and other registry studies indicate that work needs to be done in this area. Timely diagnosis of cancer when symptoms are non-specific will require an increase in the number of patients with such symptoms undergoing investigation and therefore consuming more resources. These will especially need to be deployed in areas of deprivation.