The diagnostic process of cancer from the general practitioner's point of view

Abstract

The detection of a few malignancies among the bulk of non-malignant diseases is a perpetual challenge for primary health care. The studies of this thesis were aimed to evaluate the role of GPs in the diagnostic process of cancer detection. The four most frequently diagnosed types of malignancies, colorectal, breast, pulmonary and prostate cancer, comprising approximately half of the total cancer incidence in Sweden, were studied. In order to describe the diagnostic work-up in patients with a subsequently diagnosed malignancy, medical records were studied with regards to symptom presentation and diagnostic actions. The question was then turned to describe the diagnostic actions of the GPs when patients in primary health care presented symptoms and signs, with a malignancy as a differential option among the range of non-neoplastic diseases. The socio-economic differences influencing the incidence of cancer were studied in two districts in the same urban area. Finally, an intervention study was performed with an educational programme on early symptoms of cancer in order to find out if it is possible to reduce both patientís and doctorís delay. A telephone interview and a questionnaire were used to measure potential residual anxiety caused by the programme. Most patients first consulted a GP for symptoms and signs which could be ascribed to a subsequently diagnosed malignancy. A GP can at maximum expect to diagnose approximately one case each year of each of the four cancers studied. The earliest symptom or sign of cancer for colorectal cancer was faecal blood, for breast cancer a palpable mass of the breast, for pulmonary cancer cough and for prostate cancer multiple symptoms of prostatism. Pulmonary X-ray and non-specific laboratory tests, e.g. ESR, should be reduced in favour of specific tests e.g. a faecal occult blood test, mammography, PSA and rectoscopy. Doctorís delay varied in median delay between 0 and 25 weeks in the different studies and different types of cancers. The ìmissedî cancers at the primary health care centres (17%) were mainly pulmonary cancers. The incidence of pulmonary cancer was higher in the area with low socio-economic conditions and this could be explained by higher rates of smoking. The educational programme resulted in the detection of fifteen previously unknown cancers with an indication of a reduction in both patient´s and doctor´s delay. The patients´ reaction to the information letter was positive, without any indication of increased anxiety. The GP has an important role in primary and secondary prevention, and in the detection of the few malignancies in the bulk of non-neoplastic diseases. Accurate diagnosis must be achieved with minimal cost for the diagnostic work-up and without compromising or delaying the detection of malignancies.