OBJECTIVE: To investigate the relationship between tumour stage at diagnosis and selected components of primary and secondary care in the diagnostic interval for breast, colorectal, lung and ovarian cancers.
METHODS: Observational study based on data from 6,162 newly diagnosed symptomatic cancer patients from Module 4 of the International Cancer Benchmarking Partnership. We analysed the odds of advanced stage of cancer as a flexible function of the length of primary care interval (days from first presentation to referral) and secondary care interval (days from referral to diagnosis), respectively, using logistic regression with restricted cubic splines.
RESULTS: The association between time intervals and stage was similar for each type of cancer. A statistically significant U-shaped association was seen between the secondary care interval and the diagnosis of advanced rather than localised cancer, odds decreasing from the first day onwards and increasing around three and a half months. A different pattern was seen for the primary care interval, flat trends for colorectal and lung cancers and a slightly curved association for ovarian cancer, although not statistically significant.
CONCLUSION: The results confirm previous findings that some cancers may progress even within the relatively short time frame of regulated diagnostic intervals. The study supports the current emphasis on expediting symptomatic diagnosis of cancer.