There are pronounced differences in the registered occurrence of prostate cancer in Norwegian counties, and there has been a considerable increase in the number of PSA tests carried out in recent years. We find a county-wise correlation between increased PSA testing and increased diagnosis of prostate cancer and surgical treatment of the condition, while mortality has only been moderately reduced since about 1995. Sogn og Fjordane, with the highest registered incidence of this type of cancer, exhibits a typical pattern – incidence that started rising rapidly at the time when the PSA test was introduced, in 1991. Survival shows the same rising pattern, while mortality continues to lie near the national average. This suggests overdiagnosis and overtreatment of the condition. The general practitioners in the county are aware of the authorities’ restrictive attitude to PSA screening, but often comply with their patients’ wish for a screening test nonetheless.
There are sources of error associated with the survey. Incidence and surgery rates date from the period before PSA registration in 2011. This may be one reason that we find a distinctly lower correlation with the number of PSA tests than Norderhaug et al. found in 1999 (Pearson’s r = 0.73) (14). We have not received data from all laboratories that perform the test, but this source of error is minimal, since it is a matter of two small laboratories out of a total of 49. In some cases the laboratories had difficulty in identifying the county to which some of the requisitioners belonged, and placed them in the county from which the majority of requisitioners came. This makes the analyses of the correlation between the number of PSA tests and the incidence of cancer and treatment rates somewhat uncertain.
PSA testing is used both for assessing possible prostate cancer and for monitoring patients known to have the disease. In all counties, most analyses were carried out in response to a requisition from a general practitioner, consistent with the bulk of the testing having been performed as screening and early diagnosis of cancer disease. A very large number of analyses were carried out in Oslo, but 84 % of these had been ordered by general practitioners, as in other counties. The Oslo laboratories were also able to assign the requisitioners to the counties they belonged to. There are therefore no definite indications that the high test rate in Oslo is due to referral and treatment of patients from other counties. There is a large private laboratory in Norway (the Fürst Medical Laboratory) which accepts samples from general practitioners all over Norway. This laboratory was able to account for the counties to which its requisitioners belonged.
The percentage of primary doctors from Sogn og Fjordane who responded was low (only 50 %), whereas the gender distribution and number of specialists in general medicine indicate that the respondents were representative. Experience indicates that a higher percentage of responses to questionnaires regarding the use of laboratory tests among general practitioners cannot be expected (16). However, it is possible that those who did not answer may have attitudes and practice that differ from those who responded.
Finnmark has the least PSA testing and the lowest incidence of cancer; Sogn og Fjordane has the highest incidence and also a high test rate. Oslo, however, distinguishes itself by a very large number of PSA tests that nonetheless do not take the county to the top of the cancer statistics. This may indicate that mechanisms other than PSA testing also help to determine the registered incidence. One possibility may be steadily increasing testing of «the worried well», and that this population will make up a growing number, with increasing testing frequency. Another possibility is that the PSA test is carried out on indications other than cancer screening to a greater extent here than in other counties, so that many low-risk cases are tested (17). However, our study does not give answers to these questions.
The risk of overdiagnosis followed by overtreatment has been put on the agenda as a result of screening surveys (2). Health measures that have no value in themselves will moreover entail the same risk of error and complications as when treatment is indicated, and thus may constitute a double source of potential harm for patients (2, 3). In addition, health service resources are being used that could have benefited other patient groups (4). We support efforts to increase patient safety, but they should also encompass overdiagnosis and overtreatment (18). Different forms of treatment for prostate cancer are associated with significant side effects, in addition to concerns associated with having a malignant disease diagnosed (13, 19). The primary doctors’ responses also indicate that they are aware of the risk of side effects.
The last couple of years have seen a slight decline in the registered incidence of prostate cancer in Norway. According to our data, it is doubtful whether this is due to reduced use of PSA tests. An alternative explanation may be temporary «exhaustion» of the reservoir in the population (20).
Our study does not reveal lower mortality in Sogn og Fjordane, despite the increase in treatment. This is consistent with the recently published PIVOT study with 12 years of follow-up, which also did not find reduced mortality, either all-cause or specifically for prostate cancer with radical prostatectomy, as compared with observation (21, 22). However, the Scandinavian SPCG study showed reduced mortality and metastasis following early stage radical prostatectomy (22).
Consistent with the results of our study, a recently published study shows a large increase in the number of PSA tests in the Stockholm area. It also shows that the probability of retesting was high irrespective of the original PSA level (23). Other studies from Nordic countries show a similar tendency (15).
The results of our questionnaire survey show that PSA testing is seldom initiated by routines at the primary doctors’ offices, but that it is difficult to resist patients’ expectations and fail to start the procedures that lead to the diagnosis and treatment of located tumours. A survey conducted in 2002 also showed that general practitioners agreed and complied more than urologists with the health authorities’ guidelines (14).
Specialists often act as opinion leaders both in public debate and vis-à-vis patients. As recently as in 2009, a number of urological cancer researchers stated in Tidsskriftet that we must comply with patients’ wishes with respect to PSA testing (24). This may explain why general practitioners – despite knowing that a restrictive practice is recommended – often elect to order PSA tests on lack of indication, and why there is then a tendency for «wild» screening (and a subsequent risk of overtreatment). Carlsen et al. have shown that general practitioners are vulnerable in their function of gatekeeper, and align their activities towards meeting their «customers» expectations (25).
Our findings indicate that primary doctors need help from the health authorities and the opinion leaders, for example urologists, to curb the expectations of patients and their families. Health legislation in recent decades has increasingly been characterised by requirements of informed consent and sharing in decisions concerning assessment and treatment. Methods have been developed for holding dialogues on such decisions, and IT tools have also been developed to assist doctors and patients in revealing their preferences and the dilemmas associated with medical and surgical procedures (shared decision-making) (26).
Since we do not have reliable methods at present for making a prognosis for the individual patient with detected prostate cancer, the following three approaches could potentially be used to reduce overdiagnosis and overtreatment:
Greater compliance with national guidelines for PSA testing and balanced information to relevant patient groups (shared decision-making)
A generally more wait-and-see attitude to active treatment (watchful waiting), particularly in relation to the oldest group of patients (27) and use of higher PSA threshold values (28).
Data from the Cancer Registry of Norway have been used in this article/study. The interpretation and reporting of these data are the sole responsibility of the authors, and have not been subject to approval by the Cancer Registry. We should like to thank Johanne Gulbrandsen, special consultant at the Cancer Registry’s Data Delivery Unit, Inger Helen Berge of the Western Norway Regional Health Authority’s ICT unit, Jarle Øen at the Førde Hospital Trust for electronic surveying of primary doctors in Sogn og Fjordane and trainee consultant Normund Svoen for active participation in the formulation and conducting of the survey. We should also like to thank Karl Ove Hufthammer, statistician at the Department of Gynaecology and Obstetrics, Bergen Hospital Trust, for assistance with Fig. 2.