Graft-versus-host Disease After Intestinal or Multivisceral Transplantation: A Scandinavian Single-center Experience.

BACKGROUND: Graft-versus-host disease (GVHD) that develops after intestinal or multivisceral transplantation is difficult to diagnose and is associated with high morbidity and mortality. MATERIAL AND METHODS: The objectives of this study were to investigate the incidence, clinical picture, risk factors, and outcome of GVHD in a Scandinavian cohort of patients who underwent intestinal or multivisceral transplantation during a period of 16 years (1998-2014). All transplanted patients (n = 26) were retrospectively analyzed with respect to donor- and recipient-derived risk factors. The diagnosis of GVHD was based on clinical signs, chimerism analyses of leukocytes, and histopathologic findings in biopsy specimens. RESULTS: Five of 26 patients (19%) were diagnosed with GVHD, of which three had skin GVHD, one had skin and bone marrow GVHD, and one had passenger leukocyte syndrome. Only multivisceral-transplanted patients developed GVHD. Risk factors for development of GVHD were an underlying tumor diagnosis and neoadjuvant chemo- or brachytherapy administered before intestinal transplantation. All patients were given high-dose corticosteroids as first line treatment for their GVHD, and all survived their episodes of GVHD. CONCLUSIONS: The risk of GVHD appears to be increased in recipients of multivisceral transplantations who received chemotherapy due to an underlying malignancy. The reasons may be the large amount of lymphoid tissue in these types of grafts, and the cytotoxic effects of the malignancy and chemotherapy on healthy recipient tissues. These patients should be monitored closely for the development of GVHD.

Association between PSA kinetics and cancer-specific mortality in patients with localised prostate cancer: analysis of the placebo arm of the SPCG-6 study.

BACKGROUND: The prognostic value of prostate-specific antigen (PSA) kinetics in untreated prostate cancer (PCa) patients is debatable. We investigated the association between PSA doubling time (PSAdt), PSA velocity (PSAvel) and PSAvel risk count (PSAvRC) and PCa mortality in a cohort of patients with localised PCa managed on watchful waiting. PATIENTS AND METHODS: Patients with clinically localised PCa managed observationally, who were randomised to and remained on placebo for minimum 18 months in the SPCG-6 study, were included. All patients survived at least 2 years and had a minimum of three PSA determinations available. The prognostic value of PSA kinetics was analysed and patients were stratified according to their PSA at consent: ≤10, 10.1-25, and >25 ng/ml. Cumulative incidences of PCa-specific mortality were estimated with the Aalen-Johansen method. RESULTS: Two hundred and sixty-three patients were included of which 116, 76 and 71 had a PSA at consent ≤10, 10.1-25, and >25 ng/ml, respectively. Median follow-up was 13.6 years. For patients with PSA at consent between 10.1 and 25 ng/ml, the 13-year risks of PCa mortality were associated with PSA kinetics: PSAdt ≤3 years: 62.0% versus PSAdt >3 years: 16.3% (Gray's test: P < 0.0001), PSAvel ≥2 ng/ml/year: 48.0% versus PSAvel <2 ng/ml/year: 11.0% (Gray's test: P = 0.0008), and PSAvRC 2: 45.0% versus 0-1: 3.8% (Gray's test: P = 0.001). In contrast, none of the PSA kinetics were significantly associated with changes of 13-year risks of PCa mortality in patients with PSA at consent ≤10 or >25 ng/ml. CONCLUSION: We found that magnitude changes in 13-year risks of PCa mortality that can be indicated by PSA kinetics depend on PSA level in patients with localised PCa who were managed observationally. Our results question PSA kinetics as surrogate marker for PCa mortality in patients with low and high PSA values. CLINICAL TRIAL NUMBER: NCT00672282.

Autologous haematopoietic stem cell transplantation: a viable treatment option for CIDP.

OBJECTIVE: Only 70-80% of patients with chronic inflammatory demyelinating polyneuropathy (CIDP) respond satisfactorily to the established first-line immunomodulatory treatments. Autologous haematopoietic stem cell transplantation (AHSCT) has been performed as a last treatment resort in a few therapy-refractory cases with CIDP. We describe the results of AHSCT in 11 consecutive Swedish patients with therapy-refractory CIDP with a median follow-up time of 28 months. METHOD: Case data were gathered retrospectively for AHSCT treatments in 11 patients with CIDP refractory to the first-line immunomodulatory treatments, intravenous high-dose immunoglobulin, corticosteroids and plasma exchange and to one or more second-line treatments used in 10 of the 11 patients. RESULTS: The median Inflammatory Neuropathy Cause and Treatment (INCAT) score within 1 month prior to AHSCT was 6 and the Rankin score 4. Total INCAT and Rankin scores improved significantly within 2-6 months after AHSCT and continued to do so at last follow-up. The motor action potential amplitudes (CMAP) improved already within 4 months (median) after AHSCT. Three of the 11 patients relapsed during the follow-up period, requiring retransplantation with AHSCT in one. Eight of the 11 patients maintained drug-free remission upon last follow-up. AHSCT was safe but on the short term associated with a risk of cytomegalovirus (CMV) and Epstein-Barr virus reactivation, CMV disease, haemorrhagic cystitis and pancreatitis. CONCLUSIONS: Our results though hampered by the limited number of patients and the lack of a control group suggest AHSCT to be efficacious in therapy-refractory CIDP, with a manageable complication profile. Confirmation of these results is necessary through randomised controlled trials.

Coffee consumption and risk of localized, advanced and fatal prostate cancer: a population-based prospective study.

BACKGROUND: The epidemiological evidence on possible relationships between coffee consumption and prostate cancer (PCa) risk by subtype of the disease (localized, advanced) and fatal PCa risk is limited. MATERIALS AND METHODS: A population-based cohort of 44 613 Swedish men aged 45-79 years was followed up from January 1998 through December 2010 for incidence of localized (n = 2368), advanced (n = 918) and fatal (n = 515) PCa. We assessed the associations between coffee consumption and localized, advanced and fatal PCa risk using competing-risk regressions. We examined possible effect modification by body mass index (BMI). RESULTS: For localized PCa, each one cup increase in daily coffee consumption was associated with a 3% reduced risk [sub-hazard ratio (SHR) = 0.97, 95% confidence interval (CI) = 0.95-0.99]. For advanced and fatal PCa, we found a non-significant inverse association; each one cup increase was associated with a 2% reduced risk of advanced [SHR (95% CI) = 0.98 (0.95-1.02)] and fatal PCa [SHR (95% CI) = 0.98 (0.93-1.03)]. We observed evidence of effect modification by BMI for localized PCa (Pinteraction = 0.03); the inverse association was stronger among overweight and obese men (BMI ≥ 25 kg/m(2)) compared with normal-weight men (BMI < 25 kg/m(2)). CONCLUSIONS: We observed a clear inverse association between coffee consumption and risk of localized PCa, especially among overweight and obese men.

Dietary cadmium exposure and prostate cancer incidence: a population-based prospective cohort study.

BACKGROUND: Experimental data convincingly propose the toxic metal cadmium as a prostate carcinogen. Cadmium is widely dispersed into the environment and, consequently, food is contaminated. METHODS: A population-based cohort of 41 089 Swedish men aged 45-79 years was followed prospectively from 1998 through 2009 to assess the association between food frequency questionnaire-based estimates of dietary cadmium exposure (at baseline, 1998) and incidence of prostate cancer (3085 cases, of which 894 were localised and 794 advanced) and through 2008 for prostate cancer mortality (326 fatal cases). RESULTS: Mean dietary cadmium exposure was 19 µg per day±s.d. 3.7. Multivariable-adjusted dietary cadmium exposure was positively associated with overall prostate cancer, comparing extreme tertiles; rate ratio (RR) 1.13 (95% confidence interval (CI): 1.03-1.24). For subtypes of prostate cancer, the RR was 1.29 (95% CI: 1.08-1.53) for localised, 1.05 (95% CI: 0.87-1.25) for advanced, and 1.14 (95% CI: 0.86-1.51) for fatal cases. No statistically significant difference was observed in the multivariable-adjusted risk estimates between tumour subtypes (P(heterogeneity)=0.27). For localised prostate cancer, RR was 1.55 (1.16-2.08) among men with a small waist circumference and RR 1.45 (1.15, 1.83) among ever smokers. CONCLUSION: Our findings provide support that dietary cadmium exposure may have a role in prostate cancer development.

Body mass index in early and middle-late adulthood and risk of localised, advanced and fatal prostate cancer: a population-based prospective study.

BACKGROUND: The relationships between body mass index (BMI) during early and middle-late adulthood and incidence of prostate cancer (PCa) by subtype of the disease (localised, advanced) and fatal PCa is unclear. METHODS: A population-based cohort of 36,959 Swedish men aged 45-79 years was followed up from January 1998 through December 2008 for incidence of PCa (1530 localised and 554 advanced cases were diagnosed) and through December 2007 for PCa mortality (225 fatal cases). RESULTS: From a competing-risks analysis, incidence of localised PCa was observed to be inversely associated with BMI at baseline (middle-late adulthood; rate ratio (RR) for 35 kg m(-2) when compared with 22 kg m(-2) was 0.69 (95% CI 0.52-0.92)), but not at age 30. For fatal PCa, BMI at baseline was associated with a nonstatistically significant increased risk (RR for every five-unit increase: 1.12 (0.88-1.43)) and BMI at age 30 with a decreased risk (RR for every five-unit increase: 0.72 (0.51-1.01)). CONCLUSION: Our results indicate an inverse association between obesity during middle-late, but not early adulthood, and localised PCa. They also suggest a dual association between BMI and fatal PCa--a decreased risk among men who were obese during early adulthood and an increased risk among those who were obese during middle-late adulthood.

Evaluation of a surveillance strategy for early detection of adenovirus by PCR of peripheral blood in hematopoietic SCT recipients: incidence and outcome.

Adenoviruses (AdV) have emerged as important causes of morbidity and mortality in patients after hematopoietic SCT (HSCT). Early diagnosis of the infection by detection of viral DNA may improve the prognosis. A surveillance strategy was evaluated for detection of AdV DNA by PCR in a prospective study of unselected allogeneic HSCT recipients. In parallel with a routine CMV surveillance program, plasma from 20 children and 77 adults was analyzed by quantitative PCR for detection of AdV DNA. In addition, in 12 unselected patients, the presence of AdV-specific T cells were analyzed by enzyme-linked immunosorbent spot (ELISPOT) at 1 to 3 months after transplantation. A total of 5 of 97 (5%) patients had detectable AdV DNA in peripheral blood. Only one patient had high titers and none developed AdV disease. BM as a source of stem cells and myelodysplastic syndrome as the indication for transplantation were independently associated with higher risk of acquiring AdV infection. AdV-specific T cells were detected in 7 (58%) of 12 patients. Although AdV DNA was found in peripheral blood by quantitative PCR in 5% of patients undergoing allogeneic HSCT, the present surveillance program did not have a significant effect on the clinical outcome.

Allogeneic haematopoietic stem-cell transplantation with reduced intensity conditioning for advanced stage Hodgkin's lymphoma in Sweden: high incidence of post transplant lymphoproliferative disorder.

Allogeneic transplantation after reduced intensity conditioning (allo-RIC) is a treatment option for patients with Hodgkin's lymphoma (HL) relapsing after autologous transplantation. In all, 23 adult patients with HL underwent allo-RIC in Sweden between 2000 and 2007. The median number of previous treatment lines was five and 20 patients (87%) were previously autografted. TRM at 100 days and at 1 year was 13 and 22% respectively. Acute GVHD grades II-IV developed in 7 out of 23 patients (30%) and chronic GVHD in 10 out of 20 patients at risk (50%). The OS and EFS at three years was 59 and 27%, respectively. Four patients (17%) developed post transplant lymphoproliferative disease (PTLD) after a median time of 55 days (range 38-95); two of these patients later died. The study confirmed that allo-RIC is feasible, but associated with a substantial relapse rate: only 20% of the patients were still alive 7 years after the transplant. A finding of high incidence of PTLD needs to be confirmed in a larger trial that includes patients with non-HL and CLL.

A prospective study of lifetime physical activity and prostate cancer incidence and mortality.

BACKGROUND: The possible benefit of lifetime physical activity (PA) in reducing prostate cancer incidence and mortality is unclear. METHODS: A prospective cohort of 45,887 men aged 45-79 years was followed up from January 1998 to December 2007 for prostate cancer incidence (n=2735) and to December 2006 for its subtypes and for fatal (n=190) prostate cancer. RESULTS: We observed an inverse association between lifetime (average of age 30 and 50 years, and baseline age) total PA levels and prostate cancer risk. Multivariate-adjusted incidence in the top quartile of lifetime total PA decreased by 16% (95% confidence interval (CI)=2-27%) compared with that in the bottom quartile. We also observed an inverse association between average lifetime work or occupational activity and walking or bicycling duration and prostate cancer risk. Compared with men who mostly sit during their main work or occupation, men who sit half of the time experienced a 20% lower risk (95% CI=7-31%). The rate ratio linearly decreased by 7% (95% CI=1-12%) for total, 8% (95% CI=0-16%) for localised and 12% (95% CI=2-20%) for advanced prostate cancer for every 30 min per day increment of lifetime walking or bicycling in the range of 30 to 120 min per day. CONCLUSIONS: Our results suggest that not sitting for most of the time during work or occupational activity and walking or bicycling more than 30 min per day during adult life is associated with reduced incidence of prostate cancer.

Incidence and mortality of incidental prostate cancer: a Swedish register-based study.

In a national register-based study of incidence trends and mortality of incidental prostate cancer in Sweden, we found that a significant proportion (26.6%) of affected men diagnosed died of their disease, which challenges earlier descriptions of incidental prostate cancer as a non-lethal disease.

Gut protection by palifermin during autologous haematopoietic SCT.

Conditioning therapy in connection with haematopoietic SCT (HSCT) induces a disruption of the intestinal barrier function facilitating the permeation of bacteria and endotoxin through the bowel wall with subsequent increased risk of septicaemia and a worsening of GVHD in the allogeneic setting. Palifermin (recombinant human keratinocyte growth factor) reduces the severity of oral mucositis with HSCT. The present trial investigates its effect on intestinal barrier function. Seventeen lymphoma patients undergoing autologous HSCT received palifermin. Intestinal permeability was assessed before the conditioning therapy and on days +4 and +14. Clinical oral and gastrointestinal toxicity was prospectively assessed in parallel. A comparison was made with matched historical study patients (n=21). Patients treated with palifermin had a significantly better preserved intestinal barrier function (P=0.01 on day +4) and were in less need of total parenteral nutrition (P=0.005) as compared with controls. No significant reduction of clinical gastrointestinal or oral toxicity was observed. The intestinal barrier function, normally disrupted by the conditioning therapy, is preserved by palifermin. Whether intestinal barrier preservation protects from invasive infections, and in the allogeneic setting diminishes GVHD severity, remains to be investigated in randomized controlled trials.

MUC-1 gene is associated with prostate cancer death: a 20-year follow-up of a population-based study in Sweden.

Anti-adhesion mucins have proven to play an important part in the biology of several types of cancer. Therefore, we test the hypothesis that altered expression of MUC-1 is associated with prostate cancer progression. We retrieved archival tumour tissue from a population-based cohort of 195 men with localised prostate cancer (T1a-b, Nx, M0) that has been followed for up to 20 years with watchful waiting. Semi-automated, quantitative immunohistochemistry was undertaken to evaluate MUC-1 expression. We modelled prostate cancer-specific death as a function of MUC-1 levels accounting for age, Gleason grade and tumour extent, and calculated age-adjusted and multivariate adjusted hazard ratios (HR). Men that had tumours with an MUC-intensity lower or higher than normal tissue had a higher risk of dying in prostate cancer, independent of tumour extent and Gleason score (HR 5.1 and 4.5, respectively). Adjustment for Gleason grade and tumour stage did not alter the results. Men with a Gleason score > or =7 and MUC-1 deviating from the normal had a 17 (RR=17.1 95% confidence interval=2.3-128) times higher risk to die in prostate cancer compared with men with Gleason score <7 and normal MUC-1 intensity. In summary, our data show that MUC-1 is an independent prognostic marker for prostate cancer death.

Benign prostatic hyperplasia and subsequent risk of bladder cancer.

We evaluated the risk of bladder cancer in a cohort of 79,280 Swedish men hospitalised for benign prostatic hyperplasia (BPH), identified in the Swedish Inpatient Register between 1964 and 1983 and followed until 1989 via multiple record linkages with nationwide data on cancer registry, death and emigration. Standardised incidence ratios (SIRs), the ratios of the observed to the expected numbers of incident bladder cancers, were used to calculate the risk associated with BPH. The expected number was calculated by multiplying the number of person-years by the age-specific cancer incidence rates in Sweden for each 5-year age group and calendar year of observation. Analyses were stratified by BPH treatment, latency, calendar year and presence of genitourinary (GU) comorbid conditions. After excluding the first 3 years of follow-up after the index hospitalisation, we observed 506 incident bladder cancer cases during follow-up in the cohort. No overall increased risk of bladder cancer was apparent in our main analysis involving the entire BPH cohort. However, among BPH patients with transurethral resection of the prostate (TURP), there was an increased risk in all follow-up periods; SIRs of bladder cancer during years 4-6 of follow-up was 1.22 (95% confidence interval=1.02-1.46), 1.32 for 7-9 years of follow-up, and 1.47 for 10-26 years of follow-up. SIRs of bladder cancer among TURP-treated BPH patients were particularly elevated among those with comorbid conditions of the GU tract (e.g., stone, infection, etc.); 1.72, 1.74 and 2.01 for 4-6, 7-9, 10-26 years of follow-up, respectively, and also for those whose diagnoses occurred before 1975, when TURP was more likely to be performed by a urologist than a general practitioner: 1.87, 1.90 and 1.74, respectively. These findings suggest that BPH overall is not associated with bladder cancer risk. However, among men treated with TURP, particularly those with other comorbid GU tract conditions, risk of bladder cancer was elevated.

TMPRSS2:ERG gene fusion associated with lethal prostate cancer in a watchful waiting cohort.

The identification of the TMPRSS2:ERG fusion in prostate cancer suggests that distinct molecular subtypes may define risk for disease progression. In surgical series, TMPRSS2:ERG fusion was identified in 50% of the tumors. Here, we report on a population-based cohort of men with localized prostate cancers followed by expectant (watchful waiting) therapy with 15% (17/111) TMPRSS2:ERG fusion. We identified a statistically significant association between TMPRSS2:ERG fusion and prostate cancer specific death (cumulative incidence ratio=2.7, P<0.01, 95% confidence interval=1.3-5.8). Quantitative reverse-transcription-polymerase chain reaction demonstrated high ets-related [corrected] gene (ERG) expression to be associated with TMPRSS2:ERG fusion (P<0.005). These data suggest that TMPRSS2:ERG fusion prostate cancers may have a more aggressive phenotype, possibly mediated through increased ERG expression.

Interleukin-1 receptor antagonist haplotype associated with prostate cancer risk.

IL1-RN is an important anti-inflammatory cytokine that modulate the inflammation response by binding to IL1 receptors, and as a consequence inhibits the action of proinflammatory cytokines IL1alpha and IL1beta. In this study, we hypothesise that sequence variants in the IL1-RN gene are associated with prostate cancer risk. The study population, a population-based case-control study in Sweden, consisted of 1383 prostate cancer case patients and 779 control subjects. We first selected 18 sequence variants covering the IL1-RN gene and genotyped these single-nucleotide polymorphisms (SNPs) in 96 control subjects. Gene-specific haplotypes of IL1-RN were constructed and four haplotype-tagging single-nucleotide polymorphisms (htSNPs) were identified (rs878972, rs315934, rs3087263 and rs315951) that could uniquely describe >95% of the haplotypes. All study subjects were genotyped for the four htSNPs. No significant difference in genotype frequencies between cases and controls were observed for any of the four SNPs based on a multiplicative genetic model. Overall there was no significant difference in haplotype frequencies between cases and controls; however, the prevalence of the most common haplotype (ATGC) was significantly higher among cases (38.7%) compared to controls (33.5%) (haplotype-specific P = 0.009). Evaluation of the prostate cancer risk associated with carrying the 'ATGC' haplotype revealed that homozygous carriers were at significantly increased risk (odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.2-2.2), compared to noncarriers, while no significant association was found among subjects heterozygous for the haplotype (OR = 1.0, 95% CI = 0.8-1.2). Restricting analyses to advanced prostate cancer strengthened the association between the 'ATGC' haplotype and disease risk (OR for homozygous carriers vs noncarriers 1.8, 95% CI = 1.3-2.5). In conclusion, the results from this study support the hypothesis that inflammation has a role of in the development of prostate cancer, but further studies are needed to identify the causal variants in this region and to elucidate the biological mechanism for this association.

A functional C-G polymorphism in the CYP7B1 promoter region and its different distribution in Orientals and Caucasians.

Cytochrome P450 (CYP) 7B1 is involved in many metabolic processes including androgen metabolism. Genetic variation in the CYP7B1 gene may play a role in predisposition to prostate cancer. Here, we screened the human CYP7B1 gene for possible polymorphisms. Only one single polymorphism was detected, a C-G change in the promoter -104 base pair from the transcription start site. The allele frequency was investigated in Swedish men and compared to a Korean population, as it is known that the frequency of prostate cancer is low among Orientals. We found that the frequency of the G-allele was 4.04% in Swedes (n=150) but only 0.33% among Koreans (n=153). Computer analysis indicated that the two variants bind with different affinities to a CCAAT-box binding protein. Expression studies with reporter constructs showed significantly higher transcriptional activity of the G variant in Hek293 cells (2.7-fold, P<0.05). In conclusion, we report here for the first time the detection of a single polymorphism in the CYP7B1 gene. This polymorphism is associated with phenotypic differences in an expression system and a widely different allele frequency in two ethnic populations, with great differences in the incidence of prostate cancer.

Gastric emptying after autologous haemopoietic stem-cell transplantation: a prospective trial.

Gastroparesis may be involved in the pathophysiology of prolonged nausea and vomiting after haemopoietic stem-cell transplantation (HSCT), but this has not been prospectively investigated. Gastric emptying (GE) was investigated in 20 patients before and 2 months after autologous HSCT. Gastrointestinal symptoms were graded prospectively and oral energy intake was recorded in parallel. Before transplant, all patients were asymptomatic and GE was within the reference range. Post transplant GE was delayed in three patients and three patients reported nausea and/or vomiting. Neither gastrointestinal symptoms nor oral energy intake post transplant discriminated between patients with or without delayed GE. Oral energy intake before transplant was lower (P=0.05), and there was a greater need for total parenteral nutrition (TPN) among patients who developed gastroparesis post transplant (P<0.05). Delayed GE after HSCT was found to be less common than had been believed from retrospective studies. Gastroparesis may be involved in some cases of prolonged nausea and vomiting after autologous HSCT but alternative explanations should be considered. Symptoms consistent with gastroparesis did not correlate with GE. Patients at risk of developing gastroparesis may be found among those with nutritional difficulties before and during the transplant course.

A randomised comparison of bicalutamide ('Casodex') 150 mg versus placebo as immediate therapy either alone or as adjuvant to standard care for early non-metastatic prostate cancer. First report from the Scandinavian Prostatic Cancer Group Study No. 6.

OBJECTIVES: To assess the efficacy and tolerability of bicalutamide 150 mg ('Casodex'(1)) as immediate therapy, either alone or as adjuvant to treatment of curative intent, in patients with early (T1b-T4, any N, M0) prostate cancer. METHODS: This randomised, double-blind study was conducted in the Nordic countries as part of the 'Casodex' Early Prostate Cancer programme. Patients received bicalutamide 150 mg (n=607) or placebo (n=611) in addition to standard care. RESULTS: More than 80% of patients had not received therapy of primary curative intent. Median follow-up in both groups was 3 years. Median exposure to study treatment in the bicalutamide and standard care alone groups was 2.5 and 2.3 years, respectively. Bicalutamide reduced the risk of objective disease progression by 57% compared with standard care alone (HR 0.43; 95% CI 0.34, 0.55; p<<0.0001). Survival data were immature (11.4% deaths) with no difference between the two treatment groups. CONCLUSIONS: Bicalutamide 150 mg as immediate therapy, either alone or as adjuvant to treatment of curative intent, significantly reduces the risk of disease progression in patients with early prostate cancer. The trial is ongoing to assess whether the reduction in risk of objective progression translates into an overall survival benefit.

Prostate-specific antigen for prostate cancer staging in a population-based register.

OBJECTIVE: Previous studies have shown a relationship between serum prostate-specific antigen (PSA) level and prostate tumour volume. Reports based on selected case series have also indicated that serum PSA may be used for staging, although a varying prevalence of metastasizing tumours complicates the interpretation of these studies. In order to determine the accuracy of the serum level of PSA in predicting the presence of metastases we performed a prospective cohort study of a geographically defined population of men with prostate cancer. METHODS: Serum level of PSA and the results of investigations for regional lymph node and distant metastases were recorded for all 8328 men with prostate cancer registered in the Swedish National Prostate Cancer Register 1996-1997. RESULTS: The prevalence of lymph node metastases among men who had undergone lymph node exploration was 4%, 16% and 33% for well, moderately and poorly differentiated tumours. The corresponding prevalence of distant metastases was 12%, 30% and 48%. With serum PSA <20 ng/ml as a cut-off point the negative likelihood ratios for well and moderately differentiated tumours were found to be 0.47 and 0.45 for lymph node metastases and 0.24 and 0.18 for distant metastases, resulting in post-test probabilities >92% for the exclusion of metastases. In men with poorly differentiated tumours, the negative likelihood ratio would need to be even lower to safely exclude disseminated disease. CONCLUSION: For well to moderately differentiated tumours, further investigations to assess the presence of metastases may be omitted with no great risk for understaging if serum PSA <20 ng/ml.