Background: A recent review suggests that there is no association between diagnostic and therapeutic delays and survival in colorectal cancer patients. However, the effect of tumour stage on the relationship between delay and survival in CRC should be clarified. We review here the evidence on the relationship between diagnostic and therapeutic delays and stage in colorectal cancer.
Methods: We conducted a systematic review of Medline, Embase, Cancerlit and the Cochrane Database of Systematic Reviews to identify publications published between 1965 and 2006 dealing with delay, stage and colorectal cancer. A meta-analysis was performed based on the estimation of the odds ratios (OR) and on a random effects model.
Results: We identified 50 studies, representing 18,649 patients. Thirty studies were excluded due to excessively restricted samples (e.g. exclusion of patients with intestinal obstruction or who died 1-3 months after surgery) or because they studied only a portion of the delay. Of the 37 remaining studies, great variability was noted in connection with the type of classification used for disease stage and the type of measurement used for the delay. Meta-analysis was performed based on 17 studies that included 5209 patients. The combined OR was 0.98 (95% confidence interval (CI): 0.76-1.25), suggesting a lack of association between delay and disease stage. In four studies, cancers of the colon and rectum were dealt with separately, and a meta-analysis was performed using the data for colon cancer (1001 patients) and for rectal cancer (799 patients). In both cases, the combined ORs overlapped 1.0, and showed opposite associations when studied separately: 0.86 (95% CI: 0.63-1.19) for the colon (i.e. more delay is associated with the earlier stage at diagnosis) and 1.93 (95% CI: 0.89-4.219) for the rectum (i.e. less delay is associated with the earlier stage).
Conclusions: When colorectal cancers are taken as a whole, there appears to be no association between diagnostic delay and disease stage when diagnosis is made. However, when cancers of the colon and the rectum are studied separately, there may be an opposite association. More studies about this issue are needed with larger and unrestricted samples.