Identification and early detection of cancer patients in primary care

Abstract

Aim The aim of this thesis was to investigate how general practitioners (GP) can identify patients in primary care with potential common cancers, at an early stage. It was also to design a risk assessment tool for colorectal cancer. Method Four population-based case-control studies were conducted with cancer patients diagnosed in 2011 in Region Västra Götaland, Sweden, with prostate, breast, colorectal, lung, gynaecological, and skin cancers, including malignant melanoma. Data were retrieved from the Swedish Cancer Register, the regional healthcare database and the regional repository for radiology. Results The patients’ frequency of consultation in primary care increased 50–100 days before cancer diagnosis (Paper I). More than half had consulted a GP at least four times in the year before cancer diagnosis. A considerable proportion of patients presented with early clinical features that were focal and had benign characteristics (Paper II). Bleeding combined with diarrhoea, constipation, a change in bowel habit, or abdominal pain had the highest positive predictive values of non-metastatic colorectal cancer. A risk assessment tool was designed for colorectal cancer (Paper III). Non-metastatic lung cancer could not be identified by clinical features (Paper IV). Conclusion Increased consultation frequency in primary care is a risk marker for common cancers as are focal features presented with benign characteristics. It is possible for a GP to identify patients with non-metastatic colorectal cancer by their clinical features. There is not enough evidence to suggest that patients with non-metastatic lung cancer can be identified. Keywords: cancer; consultation; diagnosis; early detection; general practice; primary health care.